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Crop biomass is the reservoir of carbon (C), a valuable input to the soil, thus supporting the soil fauna and enhancing soil health. There are limited studies that compared the major cereal crops for C storage for regenerative agriculture and to optimize C sequestration strategies. The objective of this study was to quantify the extent of variation in biomass allocation and C storage between maize (Zea mays L.), sorghum (Sorghum bicolor [L.] Moench), and wheat (Triticum aestivum L.) for crop production, and C sequestration potential. The study used metadata from 40 global studies that reported on the allocation of plant biomass and C between roots and shoots of the major cereal crops. Key statistics were computed to determine the variability between genotypes for total plant biomass (Pb), shoot biomass (Sb), root biomass (Rb), root‐to‐shoot biomass ratio (Rb/Sb), total plant carbon content, shoot carbon content, root carbon content, total plant carbon stock (PCs), shoot carbon stock, root carbon stock, and root‐to‐shoot carbon stock ratio (RCs/SCs). Maize exhibited the highest variability for Pb (with a coefficient of variation [CV] of 31.2% and a mean of 4.2 ± 1.3 Mg ha−1 year−1), followed by wheat (CV of 24.2% and a mean of 1.5 ± 0.4 Mg ha−1 year−1) and sorghum (CV of 16.8% and a mean of 2.0 ± 0.8 Mg ha−1 year−1), respectively. A similar trend was observed for PCs, with maize (CV of 40.1% and mean of 1.6 ± 0.7 Mg ha−1 year−1) showing the highest total plant C stock variability, followed by wheat (24.4% and 0.2 ± 0.1 Mg ha−1 year−1) and sorghum (16.3% and 0.9 ± 0.3 Mg ha−1 year−1), respectively. Maize (with a CV of 24.4% and mean of 0.1 ± 0.03 Mg ha−1 year−1) exhibited the highest variability for Rb/Sb, while wheat (30.92% and 0.2 ± 0.05 Mg ha−1 year−1) exhibited the highest variability for RCs/SCs. Correlation analysis revealed the following significant associations: Pb and mean annual temperature (MAT) (r = −0.47), and Sb and MAT (r = −0.43), and Pb and mean annual precipitation (MAP) (r = −0.34), and Sb and MAP (r = −0.30). Rb had a strong, significant positive correlation with MAT (r = 0.72) and MAP (r = 0.85). The meta‐analysis revealed that maize and sorghum have the highest variability for Pb and plant carbon stocks, while wheat exhibited the highest variability for the below‐ground biomass and carbon stocks. The data aided in crop selection and suggested that the best cultivars could be developed and identified for production and C sequestration potential for cultivation by farmers, land rehabilitation, and climate change mitigation. [ABSTRACT FROM AUTHOR]

Finger millet is a climate‐resilient and highly nutritious small grain crop widely grown in the semi‐arid tropics. It has multiple uses, including for food, feed and beverage preparations. However, finger millet is an under‐utilized and under‐researched crop with a mean yield of <1.0 t/ha despite a potential productivity of up to 8 t/ha. The yield gap is attributed to several production constraints, such as biotic and abiotic stresses, a lack of access to improved seeds and production inputs and poor agronomic management practices. There are valuable genetic resources and genetic variability of finger millet in its centres of diversity and global gene banks for variety design, product development and commercialization. The genetic variability can be harnessed further to integrate essential traits into candidate varieties through conventional and modern breeding methods. Breeding and genetic innovations such as genomics‐assisted breeding, mutation breeding and genome editing would accelerate finger millet breeding and new variety design and deployment. The objective of this review was to document the opportunities, challenges and prospects of finger millet improvement as a guide for variety development and deployment with enhanced grain yield and nutritional contents. The first section describes global production status and yield gains, major production and productivity challenges in finger millet. This is followed by an in‐depth presentation on breeding and genetic progress on variety development with improved agronomic and nutritional quality traits, drought and salinity tolerance, and fungal diseases, weeds and insect pest resistance. Further, the review summarized finger millet's genetic and genomic resources, reference genomes, whole genome re‐sequencing and transcriptomics of finger millet technologies, genetic engineering and genome editing and their integration with conventional breeding methods for variety design with desired end‐use traits. The review provides foundational information to expedite the development of new‐generation finger millet cultivars with desirable product profiles, including high grain yield potential, early maturity, desirable seed colour, compact head type, food and feed nutrients quality and high marketability through modern breeding approaches. [ABSTRACT FROM AUTHOR]

Pearl millet (Pennisetum glaucum [L.] R. Br., 2n = 2x = 14) is a nutrient-dense and climate-resilient crop widely cultivated in the dry regions of Africa and Asia. In Burkina Faso, the actual mean yield of the crop is < 1 ton/ha compared with a potential yield of 3 tons/ha. Several constraints, including cultivar susceptibility to the noxious weed Striga hermonthica (Del.) Bentham (Sh) and severe and recurrent drought stress limit the potential productivity of the crop. Therefore, this study aimed to determine the combining ability effects and degree of heterosis for agronomic traits and resistance to Sh among complementary pearl millet genotypes to select promising parental lines and hybrids to develop and deploy farmer-preferred varieties. The narrow-and broad-sense heritability were relatively higher for Striga-resistance (≥ 70%) and low (≤ 23%) for grain yield. The general combining ability and specific combining ability ratios were less than unity for agronomic traits and Striga reaction indicating the predominance of non-additive gene action conditioning the assessed traits. The new experimental hybrids such as IP-11358 × ICMB177111, IP-11358 × IKMB18002, IP-10579 × ICMB177002 and IP-9242 × ICMB177002 are recommended for multi-environment evaluation and production in Sh-infested pearl millet cultivation agro-ecologies in Burkina Faso or similar agro-ecologies. [ABSTRACT FROM AUTHOR]

Identification of maize germplasm with dual resistance to Striga hermonthica (Sh) and S. asiatica (Sa), could lead to the development of cultivars with stable resistance. 130 tropical and sub-tropical maize germplasms, including checks, were evaluated in a controlled environment for their reaction to Sh and Sa infestations using a 13 × 10 alpha lattice design with two replications over two seasons. Significant differences (P < 0.05) were detected among the assessed genotypes for all the recorded traits in Sh and Sa-infested treatments. Under Sa-infested conditions, mean Striga emergence counts 8 weeks after planting (SEC8) and 10 weeks after planting (SEC10) were 5.00 and 45.50, respectively, while the mean Striga damage rate 8 weeks after planting (SDR8) and 10 weeks after planting (SDR10) were 3.35 and 3.07, respectively. Under Sh-infested conditions, SEC8 and SEC10 mean values were 3.66 and 3.77, respectively, while the SDR8 and SDR10 values were 5.25 and 2.75 respectively. Positive and significant (P < 0.05) correlations were found between anthesis-silking interval (ASI) and SDR8 (r = 0.18) and SDR10 (0.32) under Sa-infested conditions. Negative and significant correlations were recorded between ear per plant (EPP) and SEC8, SDR8, and SDR10, with r = − 0.18, r = − 0.27, and r = − 0.24, respectively. Under Sh-infested conditions, significant and negative correlations were recorded between SDR8 and EPP (r = − 0. 20), EHT and SEC8 (r = − 0.22), EHT and SDR8 (r = − 0.36), PLHT and SDR8 (− 0.48), and PLHT and SDR10 (− 0.22). The results suggest that dual resistance to the two Striga species exists in some tropical and sub-tropical maize lines. The following genotypes have dual resistance to Sa and Sh: CML440, CML566, CML540, CML539, CLHP0343, CLHP0326, TZISTR1248, TZSTRI115, TZISTR25, TZISTR1205, TZSTRI113, TZISTR1119, TZISTR1174 and the OPVs B.King/1421, Shesha/1421, ZM1421, DTSTR-W SYN13, DTSTR-Y SYN14, and 2*TZECOMP3DT/WhiteDTSTRSYN) C2. The identified genotypes are suitable for use as parents in developing high-performing maize varieties with Striga resistance and improved grain yield. [ABSTRACT FROM AUTHOR]

Genetic resources of tepary bean (Phaseolus acutifolius A. Gray) germplasm collections are not well characterized due to a lack of dedicated genomic resources. There is a need to assemble genomic resources specific to tepary bean for germplasm characterization, heterotic grouping, and breeding. Therefore, the objectives of this study were to deduce the genetic groups in tepary bean germplasm collection using high-density Diversity Array Technology (DArT) based single nucleotide polymorphism (SNP) markers and select contrasting genotypes for breeding. Seventy-eight tepary bean accessions were genotyped using 10527 SNPs markers, and genetic parameters were estimated. Population structure was delineated using principal component and admixture analyses. A mean polymorphic information content (PIC) of 0.27 was recorded, indicating a relatively low genetic resolution of the developed SNPs markers. Low genetic variation (with a genetic distance [GD] = 0.32) existed in the assessed tepary bean germplasm collection. Population structure analysis identified five sub-populations through sparse non-negative matrix factorization (snmf) with high admixtures. Analysis of molecular variance indicated high genetic differentiation within populations (61.88%) and low between populations (38.12%), indicating high gene exchange. The five sub-populations exhibited variable fixation index (FST). The following genetically distant accessions were selected: Cluster 1:Tars-Tep 112, Tars-Tep 10, Tars-Tep 23, Tars-Tep-86, Tars-Tep-83, and Tars-Tep 85; Cluster 3: G40022, Tars-Tep-93, and Tars-Tep-100; Cluster 5: Zimbabwe landrace, G40017, G40143, and G40150. The distantly related and contrasting accessions are useful to initiate crosses to enhance genetic variation and for the selection of economic traits in tepary bean. [ABSTRACT FROM AUTHOR]

Drought is one of the major constraints of wheat production, especially in rainfed wheat production systems. The objective of this study was to evaluate the effects of different silicon fertilizer formulations on the agronomic performance of diverse wheat genotypes under drought‐stressed conditions. Twenty wheat genotypes were evaluated in field and greenhouse environments under non‐stressed and drought‐stressed and two silicon fertilizer formulations (granular and liquid potassium silicate) and untreated control. The four‐way interaction involving genotype, environment, water regime and silicon formulation had a significant effect (p <.05) for aboveground biomass, productive spike number, hundred seed weight and grain yield. Granular silicon application was the most effective treatment both under non‐stressed and drought‐stressed conditions compared to the liquid and control treatments. Under field and drought conditions, the highest yielding genotype was MC18, which exhibited a mean grain yield of 4.17 t ha−1 with granular silicon, 2.56 t ha−1 with liquid silicon and 2.18 t ha−1 without silicon. The yield of genotype MC18 improved by 91.3% using granular silicon under drought‐stressed and by 44.6% under non‐stressed conditions compared with the untreated control. Granular silicon positively affected the drought stress tolerance indices compared to the liquid silicon and untreated control. The principal component biplot analysis revealed that liquid and granular silicon positively impact yield response for all test genotypes under drought‐stressed and non‐stressed conditions compared with the control. Silicon application reduced genotype variation for agronomic traits and enhanced agronomic trait relationships under drought‐stressed conditions. Drought stress tolerance indices are influenced by silicon application. The effect of silicon has a direct and indirect effect on yield and yield components. Silicon fertilization can be considered as a mitigation measure to cope with the adverse effect of drought stress on wheat. [ABSTRACT FROM AUTHOR]

Induced plant mutagenesis is a powerful technique to create genetic variation for agronomic traits and drought tolerance selection programs. The objective of this study was to determine the response of elite sorghum (Sorghum bicolor [L.] Moench) lines developed via gamma-radiation for grain yield, component traits, and drought tolerance to select best performing lines for cultivation in water-stressed environments. Ten newly developed mutant lines and four check varieties were evaluated in two growing seasons under drought-stressed (DS) and non-stressed (NS) conditions in Namibia. Mutant lines were evaluated using a factorial experiment laid out in a randomized complete block design with three replications in custom-made rainout-shelter facility. Data on grain yield and yield-related traits were collected and drought tolerance selection indices were computed using mean genotype yield under non-stressed condition and drought-stressed condition. Data were subjected to standard analysis of variance, correlation and principal component analyses. The interaction effect of genotype × drought stress × season was non-significant for most assessed traits suggesting the relatively stable performance of the test lines for selection. Grain yield response of test genotypes varied from 0.55 to 2.27 t/ha under DS and 1.84 to 4.05 t/ha in NS conditions. Grain yield positively and significantly (P < 0.05) correlated with harvest index (r = 0.79), panicle weight (r = 0.75) and panicle length (r = 0.37), and negatively correlated with days to flowering (r = - 0.35) under DS condition. Principal component (PC) analysis identified two PCs accounting for 96.35 % of total genotypic variation based on drought tolerance selection indices. Biplot analysis using a combination assessed traits allowed selection of drought tolerant mutant lines designated as ML4, ML10, ML6, and ML5 with mean grain yield of 2.27, 2.05, 1.89 and 1.67 t/ha under DS conditions, in that order. The selected lines are recommended for further multi-environment evaluations for release and large-scale production in Namibia or other related agro-ecologies. [ABSTRACT FROM AUTHOR]

Yield gains in crop plants, such as citron watermelon can be realised through combining ability tests and hybrid breeding. The objective of the study was to determine the combining ability and hybrid performance of citron watermelon genotypes for agronomic traits. Five contrasting and relatively high-yielding citron watermelon genotypes were crossed in a 5 × 5 half-diallel mating design and 10 F1 hybrids were developed. The 15 families (five parents and 10 F1 hybrids) were evaluated across two environments using a randomized complete block design with three replications. Data was collected on various agronomic traits and subjected to analysis of variance (ANOVA) and combining ability analysis. Significant (P < 0.001) genotype × environment interaction effects were observed for most assessed traits. General combining ability (GCA) and specific combining ability (SCA) effects were significant (P < 0.001) for most traits. Environment × GCA was non-significant, whereas Environment × SCA effects were significant (P < 0.001) for most traits. The ratios of GCA/SCA variances were less than unity for most traits, indicating non-additive gene action of the traits. Broad-sense heritability varied from low to moderate, implying variable selection response of the assessed traits among the F1 hybrids. The parental genotypes WWM16 with positive GCA effects for fruit and seed yields and WWM66, with positive GCA effects for the number of seeds per fruit and seed yield, were identified for hybrid breeding. The following F1 hybrids: WWM04 × WWM16, WWWM03 × WWM66 and WWM16 × WWM50 with positive SCA effects on total fruit yield per plant and marketable fruit yield per plant, and WWM04 × WWM50, WWM03 × WWM16 and WWM03 × WWM66 with positive SCA effects for number of seeds per fruit and total seed yield were identified. The study identified novel and best-performing F1 hybrids of citron watermelon for economic traits and are recommended for multi-environmental evaluations, variety registration and commercialization. [ABSTRACT FROM AUTHOR]

Striga hermonthica [Del.] Benth. (Sh) is a noxious parasitic weed causing substantial yield loss in sub-Saharan Africa's pearl millet. The objective of this study was to determine the gene action and inheritance of Sh resistance in newly developed pearl millet populations to guide selection and genetic advancement. Bi-parental crosses were derived from pairs of pearl millet lines by contrasting reactions to Striga infestations. The two sets of parental lines, F1s, F2s, and backcrosses, were evaluated using a randomized complete block design with three replications. Data on the number of Striga counted at 60 and 80 days after planting were collected. The analysis of the variance showed significant (P < 0.001) differences among the generations across sets for Sh parameters. Duplicate gene action controlled the inheritance of the number of emerged Sh. Unique F2 individuals with Sh resistance were selected from the two sets for genetic advancement through recurrent selection methods for pearl millet variety development by integrating desirable agronomic and farmer-preferred traits. [ABSTRACT FROM AUTHOR]

Maize is a commodity crop providing millions of people with food, feed, industrial raw material and economic opportunities. However, maize yields in Africa are relatively stagnant and low, at a mean of 1.7 t ha−1 compared with the global average of 6 t ha−1. The yield gap can be narrowed with accelerated and precision breeding strategies that are required to develop and deploy high‐yielding and climate‐resilient maize varieties. Genomic and phenotypic selections are complementary methods that offer opportunities for the speedy choice of contrasting parents and derived progenies for hybrid breeding and commercialization. Genomic selection (GS) will shorten the crop breeding cycle by identifying and tracking desirable genotypes and aid the timeous commercialization of market‐preferred varieties. The technology, however, has not yet been fully embraced by most public and private breeding programmes, notably in Africa. This review aims to present the importance, current status, challenges and opportunities of GS to accelerate genetic gains for economic traits to speed up the breeding of high‐yielding maize varieties. The first section summarizes genomic selection and the contemporary phenotypic selection and phenotyping platforms as a foundation for GS and trait integration in maize. This is followed by highlights on the reported genetic gains and progress through phenotypic selection and GS for grain yield and yield components. Training population development, genetic design and statistical models used in GS in maize breeding are discussed. Lastly, the review summarizes the challenges of GS, including prediction accuracy, and integrates GS with speed breeding, doubled haploid breeding and genome editing technologies to increase breeding efficiency and accelerate cultivar release. The paper will guide breeders in selection and trait introgression using GS to develop cultivars preferred by the marketplace. [ABSTRACT FROM AUTHOR]

Bottle gourd [Lagenaria siceraria (Molina) Standl.] is cultivated for multiple utilities, including as a leafy vegetable, for fresh and dried fruits and seeds. It is an under-researched and -utilized crop, and modern varieties are yet to be developed and deployed in sub-Saharan Africa (SSA). There is a dire need for pre-breeding and breeding of bottle gourds for commercialization in SSA. Therefore, this study aimed to determine the combining ability and heterosis among selected genotypes of bottle gourd for fruit yield and related traits under drought-stressed and non-stressed conditions to select the best parents and hybrids. Eight preliminarily selected and contrasting parents with drought tolerance were crossed using a half-diallel mating design. The 8 parents and 28 crosses were evaluated under non-stressed (NS) and drought-stressed (DS) conditions across two growing seasons (2020/21 and 2021/22) using a 6 × 6 alpha lattice design with three replicates. Data were collected on fruit yield and related traits and subjected to analysis of variance, combining ability and heterosis analyses. Significant (p < 0.05) specific combining ability (SCA) and general combining ability (GCA) effects were computed for fruit yield per plant (FYPP). The SCA × environment and GCA × environment interaction effects were highly significant (p < 0.001) for FYPP and SYPP. The results suggest that genetic effects were affected by the test environment. Parental genotypes BG-58 and GC recorded positive and significant GCA effects for FYPP under the DS condition, whereas GC recorded positive and significant GCA effects for FYPP under the NS condition. The two genotypes are ideal breeding parents for population development to select genotypes with high fruit and seed yields. Crosses BG-27 × BG-79, BG-79 × BG-52, BG-79 × BG-70, BG-80 × BG-70, BG-80 × GC, and BG-70 × GC recorded high and positive SCA effects for FYPP and SYPP under DS condition. Crosses BG-81 × BG-52, BG-81 × GC, BG-27 × BG-79, BG-27 × GC, BG-79 × GC, BG-80 × BG-70, BG-81 × BG-58, BG-27 × BG-80, BG-27 × BG-58, BG-79 × BG-52, BG-52 × BG-58, BG-80 × BG-58, and BG-58 × BG-70 recorded high and positive SCA effects for FYPP and SYPP under NS condition. Crosses BG-80 × BG-58, BG-27 × BG-79, BG-79 × BG-52, BG-27 × BG-52, and BG-52 × BG-80 showed high and positive mid- and better-parent heterosis under DS condition for FYPP and SYPP. Crosses BG-27 × GC, BG-79 × GC, BG-27 × BG-58, and BG-27 × BG-79 showed high and positive mid- and better parent heterosis under NS condition for FYPP and SYPP. The newly selected families are recommended for multi-environment evaluation forrelease and commercialization in South Africa or similar agroecologies. [ABSTRACT FROM AUTHOR]

Increasing biomass allocation to the root system may increase soil-organic carbon stocks and confer drought adaptation in water-limited environments. Understanding the genetic bases and inheritance of biomass allocation is fundamental for drought tolerance breeding and soil health. The objective of this study was to determine the general and specific combining ability, maternal effects and the mode of gene action controlling the major yield and biomass allocation related traits in wheat to identify good combiners for breeding and enhanced carbon sequestration. Ten selected wheat genotypes were crossed in a full diallel mating design, and 90 F2 families were generated and evaluated in the field and greenhouse under drought-stressed and non-stressed conditions. Significant differences were recorded among the tested families revealing substantial variation for plant height (PH), kernels per spike (KPS), root biomass (RB), shoot biomass (SB), total plant biomass (PB) and grain yield (GY). Additive gene effects conditioned PH, SB, PB and GY under drought, suggesting the polygenic inheritance for drought tolerance. Strong maternal and reciprocal genetic effects were recorded for RB across the testing sites under drought-stressed conditions. Line BW162 had high yield and biomass production and can be used to transfer favourable genes to its progeny. The parental line LM75 maintained the general combining ability (GCA) effects in a positive and desirable direction for SB, PB and GY. Early generation selection using PH, SB, PB and GY will improve drought tolerance by exploiting additive gene action under drought conditions. Higher RB production may be maintained by a positive selection of male and female parents to capture the significant maternal and reciprocal effects found in this study. [ABSTRACT FROM AUTHOR]

Pearl millet (Pennisetum glaucum [L.] R. Br.) is a nutrient-dense, relatively drought-tolerant cereal crop cultivated in dry regions worldwide. The crop is under-researched, and its grain yield is low (< 0.8 tons ha−1) and stagnant in the major production regions, including Burkina Faso. The low productivity of pearl millet is mainly attributable to a lack of improved varieties, Striga hermonthica [Sh] infestation, downy mildew infection, and recurrent heat and drought stress. Developing high-yielding and Striga-resistant pearl millet varieties that satisfy the farmers’ and market needs requires the identification of yield-promoting genes linked to economic traits to facilitate marker-assisted selection and gene pyramiding. The objective of this study was to undertake genome-wide association analyses of agronomic traits and Sh resistance among 150 pearl millet genotypes to identify genetic markers for marker-assisted breeding and trait introgression. The pearl millet genotypes were phenotyped in Sh hotspot fields and screen house conditions. Twenty-nine million single nucleotide polymorphisms (SNPs) initially generated from 345 pearl millet genotypes were filtered, and 256 K SNPs were selected and used in the present study. Phenotypic data were collected on days to flowering, plant height, number of tillers, panicle length, panicle weight, thousand-grain weight, grain weight, number of emerged Striga and area under the Striga number progress curve (ASNPC). Agronomic and Sh parameters were subjected to combined analysis of variance, while genome-wide association analysis was performed on phenotypic and SNPs data. Significant differences (P < 0.001) were detected among the assessed pearl millet genotypes for Sh parameters and agronomic traits. Further, there were significant genotype by Sh interaction for the number of Sh and ASNPC. Twenty-eight SNPs were significantly associated with a low number of emerged Sh located on chromosomes 1, 2, 3, 4, 6, and 7. Four SNPs were associated with days-to-50%-flowering on chromosomes 3, 5, 6, and 7, while five were associated with panicle length on chromosomes 2, 3, and 4. Seven SNPs were linked to thousand-grain weight on chromosomes 2, 3, and 6. The putative SNP markers associated with a low number of emerged Sh and agronomic traits in the assessed genotypes are valuable genomic resources for accelerated breeding and variety deployment of pearl millet with Sh resistance and farmer- and market-preferred agronomic traits. [ABSTRACT FROM AUTHOR]

Assessing the genetic diversity and population structure of cultivated sorghum is important for heterotic grouping, breeding population development, marker-assisted cultivar development, and release. The objectives of the present study were to assess the genetic diversity and deduce the population structure of 200 sorghum accessions using diversity arrays technology (DArT)-derived single nucleotide polymorphism (SNP) markers. The expected heterozygosity values ranged from 0.10 to 0.50 with an average of 0.32, while the average observed heterozygosity (0.15) was relatively low, which is a typical value for autogamous crops species like sorghum. Moderate polymorphic information content (PIC) values were identified with a mean of 0.26, which indicates the informativeness of the chosen SNP markers. The population structure and cluster analyses revealed four main clusters with a high level of genetic diversity among the accessions studied. The variation within populations (41.5%) was significantly higher than that among populations (30.8%) and between samples within the structure (27.7%). The study identified distantly related sorghum accessions such as SAMSORG 48, KAURA RED GLUME; Gadam, AS 152; CSRO1, ICNSL2014-062; and YALAI, KAFI MORI. The accessions exhibited wide genetic diversity that will be useful in developing new gene pools and novel genotypes for West Africa sorghum breeding programs. [ABSTRACT FROM AUTHOR]

Maize cultivars with resistance to Striga spp. and compatible to Fusarium oxysporum f.sp. strigae (FOS) are an economical, sustainable and environmentally Striga control option. This study's objective was to determine the type and magnitude of gene action controlling grain yield and yield‐related components, Striga resistance, FOS compatibility and to select promising maize genotypes for an integrated Striga management approach. Ninety‐nine experimental hybrids, generated by a North Carolina mating design II, were evaluated with and without FOS treatment at three Striga‐infested sites in western Tanzania. The general (GCA), and specific combining ability (SCA) effects were significant (P <.05) for all the assessed traits with and without FOS except, Striga damage ratings eight (SDR8), and 10 (SDR10) weeks after planting with FOS treatment. FOS‐treated progenies had fewer emerged Striga plants than untreated controls. Parental genotypes such as SITUKA M1, TZA4010, TZA4016, TZA4203, JL01, JL05, JL13 and JL17 showed negative GCA effects for all Striga parameters and positive GCA effects for grain yield. The new progenies and selected parents are recommended for Striga resistance breeding. [ABSTRACT FROM AUTHOR]

Profiling the genetic diversity of germplasm collections is fundamental for selection programs and strategic conservation. Citron watermelon (Citrullus lanatus var. citroides [L.H. Bailey] Mansf. ex Greb.) is an under-researched cucurbit crop despite providing food and nutritional security in sub-Saharan Africa. There is limited information on genetic relationships of South African citron watermelon accessions for effective breeding. The objective of this study was to determine the extent of genetic diversity among 48 South African citron watermelon landrace accessions using selected simple sequence repeat (SSR) markers to identify genetically divergent accessions for trait integration and variety development. The SSR markers amplified a total of 24 alleles, with a mean expected heterozygosity value of 0.38, indicating moderate genetic diversity among the studied accessions. The mean polymorphic information content value of 0.21 indicated low discriminatory power of the SSR markers. Analysis of molecular variance attributed 8%, 75%, and 17% of the molecular variation between populations, among accessions and within accessions, respectively. Three distinctive genetic groups were identified based on cluster analysis, which aided the selection of genetically diverse citron watermelon accessions for breeding and cultivar development. [ABSTRACT FROM AUTHOR]

Powdery mildew (PM) of wheat caused by Blumeria graminis f. sp. tritici is among the most important wheat diseases, causing significant yield and quality losses in many countries worldwide. Considerable progress has been made in resistance breeding to mitigate powdery mildew. Genetic host resistance employs either race-specific (qualitative) resistance, race-non-specific (quantitative), or a combination of both. Over recent decades, efforts to identify host resistance traits to powdery mildew have led to the discovery of over 240 genes and quantitative trait loci (QTLs) across all 21 wheat chromosomes. Sources of PM resistance in wheat include landraces, synthetic, cultivated, and wild species. The resistance identified in various genetic resources is transferred to the elite genetic background of a well-adapted cultivar with minimum linkage drag using advanced breeding and selection approaches. In this effort, wheat landraces have emerged as an important source of allelic and genetic diversity, which is highly valuable for developing new PM-resistant cultivars. However, most landraces have not been characterized for PM resistance, limiting their use in breeding programs. PM resistance is a polygenic trait; therefore, the degree of such resistance is mostly influenced by environmental conditions. Another challenge in breeding for PM resistance has been the lack of consistent disease pressure in multi-environment trials, which compromises phenotypic selection efficiency. It is therefore imperative to complement conventional breeding technologies with molecular breeding to improve selection efficiency. High-throughput genotyping techniques, based on chip array or sequencing, have increased the capacity to identify the genetic basis of PM resistance. However, developing PM-resistant cultivars is still challenging, and there is a need to harness the potential of new approaches to accelerate breeding progress. The main objective of this review is to describe the status of breeding for powdery mildew resistance, as well as the latest discoveries that offer novel ways to achieve durable PM resistance. Major topics discussed in the review include the genetic basis of PM resistance in wheat, available genetic resources for race-specific and adult-plant resistance to PM, important gene banks, and conventional and complimentary molecular breeding approaches, with an emphasis on marker-assisted selection (MAS). [ABSTRACT FROM AUTHOR]

Parasitic Striga weeds severely damage cereal crops in sub‐Saharan Africa (SSA), leading to yield losses in susceptible varieties. A range of Striga control methods are commonly recommended, including cultural practices, chemical herbicides, biological control agents, and host resistance, either as solo treatments or in combinations of these approaches (i.e., integrated Striga management [ISM]). A limited number of studies compared the relative efficacy of the recommended Striga control methods, or their combinations for ISM, in cereal crop production in SSA. The objective of this paper was to undertake a meta‐analysis and provide a detailed comparison of the Striga control methods in the production of maize, sorghum, and the major millets, as a guide to effective Striga management. The study was conducted as a meta‐analysis of 66 research articles that reported on various control measures. The following agronomic data were collected: grain yield (GY) response of the assessed crops and Striga parameters such as damage rating score (SDR) and emergence count (SEC). Maize varieties possessing Striga‐resistant genes displayed high mean yield values at 2053.00 kg ha−1, varying from 281.00 to 6260.00 kg ha−1, and a mean SDR of 4.70, ranging from 2.00 to 7.00. Likewise, sorghum varieties with Striga resistance genes achieved greater GY with a mean yield response of 1738.00 kg ha−1, ranging from 850.00 to 2162.00 kg ha−1. A relatively low GY was achieved in maize and sorghum production when deploying ISM (e.g., cultural control + host resistance and host resistance + chemical herbicides) and chemical Striga control. Effective ISM and pre‐ and post‐emergent herbicides have not yet been identified for Striga control and yield gains. Striga damage negatively affected GY in maize, as revealed by the significant correlation (r = −0.36, P < 0.001) between GY and SDR. A relatively weak correlation was detected in maize between GY and SEC (r = 0.003, P = 0.96). Sorghum GY was negatively correlated with SEC, although nonsignificantly (r = −0.30, P = 0.36). Few studies have evaluated Striga control methods in pearl millet and finger millet, limiting the opportunity for an effective comparison. The study recommends SDR as the best selection criterion for improving GY performance in maize, while SEC and SDR are the parameters of choice in sorghum selection programs for better GY under Striga infestation. Overall, the meta‐analysis indicates that host resistance is the most effective method for controlling Striga infestation and boosting GY in maize and sorghum. There is an ongoing need for research into the best combinations of the reported control methods as a sound basis for the recommendation of an ISM package across target production environments of common cereals in Africa. Core Ideas: Maize and sorghum varieties that are resistant to Striga displayed high mean yield values under Striga infestation.Effective ISM and pre‐and post‐emergent herbicides have not yet been identified for Striga control and yield gains.Host resistance is the most effective method for controlling Striga and boosting yield in maize and sorghum.There is a need to investigate the best combinations of the reported control methods to recommend an ISM package.Few studies have evaluated Striga control methods in pearl millet and finger millet limiting effective comparison. [ABSTRACT FROM AUTHOR]

Physiological and complementary phenotypic traits are essential in the selection of drought-adapted crop genotypes. Understanding the physiological response of diverse okra genotypes under drought stress conditions is critical to the selection of drought-tolerant accessions for production or breeding. The objective of this study was to assess the levels of drought tolerance in preliminarily selected okra accessions based on leaf gas exchange and chlorophyll fluorescence to determine best-performing genotypes for drought-tolerance breeding. Twenty-six genetically diverse okra accessions were screened under non-stressed (NS) and drought-stressed (DS) conditions under a controlled glasshouse environment using a 13 × 2 alpha lattice design in three replicates, in two growing seasons. Data were subjected to statistical analyses using various procedures. A significant genotype × water condition interaction effect was recorded for transpiration rate (T), net CO2 assimilation (A), intrinsic water use efficiency (WUEi), instantaneous water use efficiency (WUEins), minimum fluorescence (Fo′), maximum fluorescence (Fm′), maximum quantum efficiency of photosystem II photochemistry (Fv′/Fm′), the effective quantum efficiency of PSII photochemistry (ɸPSII), photochemical quenching (qP), nonphotochemical quenching (qN) and relative measure of electron transport to oxygen molecules (ETR/A). The results suggested variable drought tolerance of the studied okra accessions for selection. Seven principal components (PCs) contributing to 82% of the total variation for assessed physiological traits were identified under DS conditions. Leaf gas exchange parameters, T, A and WUEi, and chlorophyll fluorescence parameters such as the ɸPSII, Fv′/Fm′, qP, qN, ETR and ETR/A had high loading scores and correlated with WUEi, the ɸPSII, qP and ETR under DS conditions. The study found that optimal gas exchange and photoprotection enhance drought adaptation in the assessed okra genotypes and tested water regimes. Using the physiological variables, the study identified drought-tolerant accessions, namely LS05, LS06, LS07 and LS08 based on high A, T, Fm′, Fv′/Fm′ and ETR, and LS10, LS11, LS18 and LS23 based on high AES, Ci, Ci/Ca, WUEi, WUEins, ɸPSII and AES. The selected genotypes are high-yielding (≥5 g/plant) under drought stress conditions and will complement phenotypic data and guide breeding for water-limited agro-ecologies. [ABSTRACT FROM AUTHOR]

The parasitic weed, Striga species, is among the major causes of yield and quality losses of cereal and legume crops in sub-Saharan Africa. The development of nutritionally enhanced genetic resources with Striga resistance is an overriding consideration in sorghum breeding programs. The objective of this study was to determine the genetic variability among 12 elite and newly bred sorghum (Sorghum bicolor (L.) Moench) lines with variable Striga resistance for agronomic performance and nutritional traits. The sorghum genotypes were analyzed for protein, amino acid profiles, and selected minerals. For agronomic traits, significant variations were observed for yield per plant that varied from 51.74 to 15.12 g/plant, with a mean of 29.77 g/plant. The tested genotypes showed significant (p < 0.05) variation in protein, amino acid, iron, and zinc contents. The crude protein content varied from 9.59 to 13.60%, with a mean of 11.64%. The lysine values ranged from 1.13 to 3.08%, with a mean of 2.15%, while methionine content varied from 0.42 to 1.58%, with a mean of 0.87%. Iron content ranged from 35.26 to 156.32 mg/kg with a mean of 78.32 mg/kg, while zinc content varied from 14.45 to 44.46 mg/kg with a mean of 24.91 mg/kg. The following genotypes: AS1, PAN8816, 672, Macia, AS436, 3984 × 630, AS426 × 672, and 105 × 654 were identified as having superior agronomic and nutritional qualities for commercialization and sorghum breeding programs. [ABSTRACT FROM AUTHOR]

Sorghum (Sorghum bicolor (L.) Moench) is the main food staple for millions of people in Sub-Saharan Africa (SSA) and Asia. Sorghum is relatively drought tolerant and cultivated in arid and semi-arid regions under rain-fed production. However, severe drought stress often leads to crop loss and declined productivity. The development and deployment of high-yielding and drought-adapted genotypes is a cost-effective strategy for sustainable sorghum production globally. The objective of this study was to determine drought tolerance and genotype-by-environment interaction (GEI) effects on grain yields of a population of African sorghum genotypes to identify high-yielding and drought-adapted genotypes for direct production and also for use in breeding programs. Two hundred and twenty-five sorghum genotypes were evaluated under non-stressed (NS), pre-anthesis drought stress (PreADS), and post-anthesis drought stress (PoADS) conditions under field and greenhouse environments using a 15 × 15 alpha lattice design in two replicates. The three water regimes and two environments resulted in six testing environments. Data were collected on grain yield and drought tolerance parameters, and additive main effect and multiplicative interaction (AMMI) analysis were computed. The mean grain yield under NS, PreADS, and PoADS were 3.70, 1.76, and 2.58 t/ha, in that order. The best genotypes adapted to non-stressed environments were G09, and G109, whereas G114 and G56 were suitable for non-stressed and stressed conditions. G72 and G75 displayed the best performance in PreADS conditions only, whereas genotypes G210 and G12 were identified as high performers under PoADS only. The AMMI analysis revealed that genotype (G), environment (E), and GEI were significant (p < 0.05), which accounted for 38.7, 44.6, and 16.6% of the total explained variation in grain yield. AMMI 4 was the best-fitting model for grain yield. Based on AMMI 4 and the Best Linear Unbiased Estimates (BLUPs) calculations, genotypes G119 and G127 with a grain yield of 5.6 t/ha and 6.3 t/ha were selected as being suitable for non-stressed conditions. Genotypes G8 and G71 with BLUPs of 2.5 t/ha and 2.6 t/ha were best-suited for pre-anthesis drought stress conditions, whereas genotypes G115 and G120 with BLUPs of 4.2 t/ha and 4.3 t/ha are recommended for post-anthesis drought-prone environments, respectively. The identified sorghum genotypes are recommended for production in dry agro-ecologies of sub-Saharan Africa characterized by pre-and-post anthesis drought stress. In addition, the identified genotypes are valuable genetic resources to develop novel drought-tolerance material. [ABSTRACT FROM AUTHOR]

Genotype-by-environment (GEI) analysis guides the recommendation of best-performing crop genotypes and production environments. The objective of this study was to determine the extent of GEI on seed yield in tepary bean for genotype recommendation and cultivation in drought-prone environments. Forty-five genetically diverse tepary bean genotypes were evaluated under non-stressed and drought-stressed conditions for two seasons using a 9 × 5 alpha lattice design with three replications in four testing environments. Data were collected on seed yield (SY) and days to physiological maturity (DTM) and computed using a combined analysis of variance, the additive main effect and multiplicative interaction (AMMI), the best linear unbiased predictors (BLUPs), the yield stability index (YSI), the weighted average of absolute scores (WAASB) index, the multi-trait stability index (MTSI), and a superiority measure. AMMI analysis revealed a significant (p < 0.001) GEI, accounting for 13.82% of the total variation. Genotype performance was variable across the test environments, allowing the selection of best-suited candidates for the target production environment. The environment accounted for a substantial yield variation of 52.62%. The first and second interaction principal component axes accounted for 94.8 and 4.7% of the total variation in the AMMI-2 model, respectively, of surmountable variation due to GEI. The AMMI 2 model family was sufficient to guide the selection of high-yielding and stable genotypes. Based on best linear unbiased predictors (BLUPs), yield stability index (YSI), superiority measure (Pi), and broad adaptation, the following tepary bean genotypes were identified as high-yielding and suited for drought-prone environments: G40138, G40148, G40140, G40135, and G40158. The selected tepary bean genotypes are recommended for cultivation and breeding in Malawi or other related agroecologies. [ABSTRACT FROM AUTHOR]

The root system is vital for anchorage, mobilizing water and nutrients and symbiosis with soil microbes, which influence adaptation and crop performance. However, root traits are not widely used in crop variety development because root phenotyping is difficult and there is limited understanding of the genetics of root traits. The available genetic variation and emerging root phenotyping and genotyping technologies present opportunities for integrating root traits in breeding. Selection efficiency for root traits can be enhanced by integrating shovelomics, digital imaging, crop modelling and gene sequencing systems. Therefore, the objectives of this review are to discuss critical root traits and their vital functions, genetic variation present for root traits, opportunities and challenges in root phenotyping and integration of genomic tools in breeding for improved root systems. The information presented in the paper will guide crop breeders in developing a new generation of crop varieties with desirable yield and root traits. [ABSTRACT FROM AUTHOR]

Knowledge of genetic interrelationships and grouping among pigeonpea germplasm collections is fundamental to selecting breeding parents with unique genetic constitutions. The objectives of this study were to assess the genetic diversity and genetic grouping present among 81 pigeonpea genotypes collected from Malawi, Tanzania and Kenya using 4122 single nucleotide polymorphism (SNP) markers and complementary morphological traits. The SNP markers and phenotypic traits revealed significant genetic variation among the assessed genotypes. The test genotypes were resolved into three distinct clusters based on both marker systems. The mean gene diversity and the polymorphic information content (PIC) were 0.14 and 0.11, suggesting moderate genetic differentiation among the genotypes. The analysis of molecular variance revealed that differences among populations accounted for only 2.7% of the variation, while within the population (among individuals) accounted for 97.3% of the variation. The results based on the DArT SNP genotyping complemented the phenotypic data and led to the selection of unique pigeonpea genotypes for effective breeding programs in Malawi and related agroecologies. This suggested that unique breeding populations could be created by identifying and selecting divergent individuals as parental lines. There is a need to create a new genetic variation or introgress genes from genetically unrelated parents to increase the genetic base of the current pigeonpea breeding populations. [ABSTRACT FROM AUTHOR]

Keywords: area under pest progress curve; fall armyworm; host-plant resistance; infestation level; stages of life cycle; FAW rearing; pest reaction type; resistance breeding EN area under pest progress curve fall armyworm host-plant resistance infestation level stages of life cycle FAW rearing pest reaction type resistance breeding 1020 22 11/17/22 20221101 NES 221101 1. Area under pest progress curve, fall armyworm, host-plant resistance, infestation level, stages of life cycle, FAW rearing, pest reaction type, resistance breeding Developmental Stages of FAW under Laboratory Conditions The average times taken, in days, to complete each FAW life cycle stage obtained through the monitoring of FAW individuals from seven egg batches (A to G) were subjected to analysis of variance (ANOVA) using Genstat 18th edition [[40]]. Assessing the Survival Rate of FAW Larvae on the Natural and Artificial Diets Eight sets of FAW larvae (set A), each with 15 neonate larvae, were set aside from a newly hatched egg batch and maintained on a natural diet containing maize leaves and stalks. [Extracted from the article]

Combining ability analysis is fundamental in breeding programs to select desirable parents and progenies. The objectives of this study were to determine the combining ability effects, and gene action controlling agronomic traits and resistance to Fusarium wilt (FW) caused by Fusarium udum Butler in pigeonpea [Cajanus cajan (L.) Millspaugh]. Twenty-five progenies were developed from 10 selected parents using a 5 × 5 North Carolina Design II. The progenies and their parents were assessed for agronomic traits and FW resistance. The genotypes were subjected to artificial FW infection using a root dip inoculation technique to evaluate seedling resistance. ICEAP 87105 and ICEAP 01285 had significantly negative general combining ability (GCA) effects for days to 75% maturity (DTM), whereas MWPLR 22, Sauma and Mwayiwathualimi had positive GCA effects for grain yield (GYD) in a desirable direction. The study selected the best hybrids such as ICEAP 01285 × MWPLR 14 for early maturity, FW resistance and a high GYD, and TZA 5582 × ICEAP 00554, TZA 5582 × MWPLR 14, and Mwayiwathualimi × MWPLR 22 for FW resistance and a high GYD. The narrow-sense heritability values varied from 27% (number of seeds per plant) to 97% (DTM). Parental lines TZA 5582 and MWPLR 14 made strong contributions to desirable gene combinations that improved agronomic traits in the selected crosses. The new hybrids form novel breeding populations useful in improving the traits of economic importance in pigeonpea. [ABSTRACT FROM AUTHOR]

The magnitude of genotype by environment interaction (GEI) is crucial for selecting high performing and adapted genotypes for targeted breeding. The aim of the study was to determine GEI of newly-developed mutant and traditional sorghum lines for grain yield and yield related traits for drought-prone areas of Namibia. Fifty sorghum genotypes were evaluated under field conditions using a 10 × 5 alpha lattice design with three replications. The experiments were carried out in four environments with two growing seasons in Namibia. Data were collected on grain yield and related traits and subjected to the Additive Main Effects and Multiplicative Interaction (AMMI) model. The AMMI model showed that 93.9% of the total genetic variation was attributed to days to 50% flowering (DF), while 94.04% of the variation was due to plant height (PH), 86.52% to panicle weight (PW), 70.67% to thousand-grain weight (TGW), and 90.68% to grain yield (GY). The larger variations attributed to genotypic effects for PL (36.3%), TGW (33.2%) and PH (20.7%) are useful for genotype selection for yield related traits. Based on a multi-trait biplot and Best Linear Unbiased Prediction (BLUPs) analyses of the GEI data across all drought-prone testing environments, the medium maturity mutant line designated as L7P9-13 was selected as the best yielding (2 tons/ha) and recommended for drought-prone area of Namibia. [ABSTRACT FROM AUTHOR]

Genetic diversity analysis of crop genetic resources is a prerequisite for parental selection with suitable and complementary profiles for breeding. The objectives of this study were to determine genetic diversity present among okra accessions using simple sequence repeat (SSR) and complementary phenotypic markers and to select genetically divergent and superior parental accessions for pre-breeding. Twenty-six preliminarily selected okra accessions were assessed using nine highly polymorphic SSR markers and phenotyped under drought-stressed (DS) and non-stressed (NS) environmental conditions using a 13 × 2 alpha lattice design with two replications. Data were collected on the following eleven phenotypic traits: plant height (PH), days to 50% maturity (DTM), fresh pod length (FPL), dry pod weight (DPW), dry pod length (DPL), number of pods per plant (NPPP), pod yield per plant (PYPP), total above-ground biomass (AGB), harvest index (HI), root weight (RW), and root to shoot ratio (RSR). The SSR markers revealed an expected mean heterozygosity value of 0.54, indicating moderate genetic diversity among the tested okra accessions. Cluster analysis based on phenotypic and SSR markers differentiated the accessions into three distinct genetic groups. Wide phenotypic variation was observed for PH, FPL, NPPP, and PYPP under NS and DS conditions. PYPP was positively and significantly correlated with FPL (r = 0.81), ABG (r = 0.69), and HI (r = 0.67) under DS conditions, and FPL (r = 0.83) and AGB (r = 0.60) under NS conditions. Genetically complementary accessions such as LS04, LS05, LS06, LS07, LS08, LS10, LS11, LS15, LS18, LS23, LS24, and LS26 were identified for their high yield potential and related yield-improving traits under DS conditions. The identified accessions are recommended as parents for hybridization and selection programs to improve the yield potential of okra under drought-stressed environments. [ABSTRACT FROM AUTHOR]

Sesame production and productivity are severely constrained by a lack of high-yielding and locally adapted varieties, susceptibility to capsule shattering and low seed retention, biotic and abiotic stresses, and a lack of modern production and pre- and post-harvest technologies. Unimproved landraces are widely cultivated in sub-Saharan Africa, including Ethiopia. The landrace varieties are low yielders (<0.6 tons·ha−1), but they possess intrinsic seed oil quality characteristics, such as unique aroma and taste. Therefore, current and future sesame genetic improvement programs should integrate yield- and quality-promoting traits, local adaptation, amenability to machine harvesting, and other industrially essential food and feed attributes for multiple utilities. This can be achieved by integrating the conventional breeding methods, as well as genetic and genomic techniques such as mutation breeding and genomics-assisted breeding. Therefore, the objective of this review is to document the breeding progress, opportunities, and challenges of sesame with regard to genetic improvement, variety release, and deployment with enhanced seed yield and related agronomic traits, as well as oil content and fatty acid compositions. The review highlights sesame's economic values, production status, major production constraints, conventional breeding methods, and genomics-assisted breeding, as well as their integration, for accelerated breeding and cultivar development with market-preferred traits. [ABSTRACT FROM AUTHOR]

Understanding the genetic basis of a crop's qualitative and quantitative traits is vital to designing market preferred varieties. The aim of this review is to present a retrospective genetic analysis of qualitative and quantitative phenotypic traits in sweet watermelon as a guide for trait integration and the development of novel varieties with yield potential and desirable horticultural attributes. The first section outlines genes conditioning the inheritance of plant architecture (e.g., leaf attributes and plant architecture), floral characters (flowering rate, sex expression, and male sterility), fruit traits (shape, colour, rind colour and stripe patterns and flesh colour) and seed morphology (seed length, width, size and coat colour). In the second section, developments in molecular markers and quantitative trait loci (QTL) to aid marker-assisted breeding are discussed. Further, the review highlights the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) gene-editing technology and its scope in gene manipulations and new variety development. The information presented in this review is useful for optimised and demand-led breeding to develop new varieties to serve growers, consumers and the sweet watermelon industry. [ABSTRACT FROM AUTHOR]

Sorghum hybrids can provide enhanced bioethanol yield if genetically complementary parents and progenies are developed using efficient crossing and selection methods. The objective of this study was to determine the combining ability of sweet stem sorghum genotypes, and assess heterosis among F1 hybrids for ethanol production and associated traits. Eight sweet stem sorghum lines and four testers were crossed using a line × tester mating design. The F1 hybrids and parental lines were evaluated for bioethanol yield and related traits. Data were subjected to analysis of variance, combining ability and heterosis analyses. Biomass production of test populations varied from 11.6 to 68 t ha−1, with a mean of 30 t ha−1. Six hybrids were among the top ten biomass producing genotypes. Four hybrids (AS391 × AS246, AS204 × AS251, AS204 × AS79, AS204 × AS74) expressed greater ethanol productivity with positive better-parent heterosis (> 30%). Lines AS253, AS246 and AS 105, and testers AS391 and SS27 had highly positive general combining ability (GCA) effects for almost all the traits in a desirable direction. Due to its consistent, significant and positive GCA effects across the majority of the traits, line AS253 is recommended for utilisation in sweet stem sorghum hybrid programs. [ABSTRACT FROM AUTHOR]

Genetic diversity is invaluable in developing climate-smart and drought-adapted wheat varieties. The aim of this study was to determine the extent of genetic variation present in wheat germplasm collections for biomass allocation and drought tolerance based on complementary phenotypic and root attributes and high-density single nucleotide polymorphism (SNP) markers to select breeding parents. A total of 97 bread wheat (Triticum aestivum L.) genotypes were evaluated in field and greenhouse trials under drought-stressed and non-stressed conditions. The molecular variance analysis showed that the intrapopulation variance was very high at 99%, with a small minimal inter-population variance (1%). The genetic distance, polymorphic information content and expected heterozygosity were 0.20–0.88, 0.24–1.00 and 0.29–0.58, respectively. The cluster analysis based on SNP data showed that 44% and 28% of the assessed genotypes maintained their genetic groups when compared to hierarchical clusters under drought-stressed and non-stressed phenotypic data, respectively. The joint analysis using genotypic and phenotypic data resolved three heterotic groups and allowed the selection of genotypes BW140, BW152, BW157, BW162, LM30, LM47, LM48, LM52, LM54 and LM70. The selected genotypes were the most genetically divergent with high root biomass and grain yield and are recommended for production or breeding. [ABSTRACT FROM AUTHOR]

Drought stress and nitrogen (N) deficiency are the major causes of yield losses in bread wheat (Triticum aestivum) production. Breeding wheat cultivars with combined drought and low N stress tolerance is an economical approach for yield gains. The objective of this study was to evaluate the response of diverse bread wheat genotypes under drought and low N stress conditions to select high-performing genotypes for developing breeding populations and production to mitigate against drought and low N stress. Fifty bread wheat genotypes were evaluated under drought-stressed (DS) and non-stressed (NS) conditions and N application rates of 50, 100 and 200 kg N ha−1. The experiments were conducted in a controlled environment and field conditions during the 2019/20 cropping season. Data on grain yield and yield components were collected and subjected to statistical analysis. The four-way interaction involving genotype, water regime, N treatments and testing environment had a significant (p < 0.05) effect on all assessed agronomic traits, suggesting that genotype response depended on the treatment combinations. Drought stress and 50 kg N ha−1 reduced grain yield by 20% compared to NS and 50 kg N ha−1. The grain yield ranged from 120 to 337 g/m2, with a mean of 228 g/m2 under DS. Under DS and 200 kg N ha−1, the genotype designated as SBO 19 had a higher grain yield of 337 g/m2, followed by SBO 22 (335 g/m2), SBO 16 (335 g/m2), SBO 04 (335 g/m2) and SBO 33 (335 g/m2). Grain yields under DS and 50 kg N ha−1, and NS and 50 kg N ha−1 had a positive and significant correlation (r > 0.5; p < 0.01) with most of the evaluated traits. Highly correlated traits directly contribute to total yield gain and should be incorporated during the selection of high-yielding genotypes. The study identified the 10 best lines that are high-yielding with early flowering and maturity under DS or NS conditions and the three N treatments. The selected lines are recommended as breeding parents to develop drought-adapted and N-use efficient genetic resources. The identified genotypes are important for sustainable wheat production and effective breeding of improved cultivars to mitigate drought stress and soil nutrient deficiencies, to ensure food security in Sub-Saharan Africa. [ABSTRACT FROM AUTHOR]

Agriculture accounts for 70% of the global use of available freshwater. Projections show that demand for water will increase significantly due to climate change, population growth and development of agricultural enterprises globally. There is a need to develop water‐use efficient crop cultivars for sustainable agricultural production. Sorghum [Sorghum bicolor (L.) Moench.] is a powerhouse crop in drier regions supporting more than 500 million people. It is a relatively drought‐tolerant crop adapted to grow and yield in marginal environments where other dominant crops such as maize and wheat fail to survive. However, the mean yield of sorghum in the semi‐arid regions has stagnated around 1.0 ton/ha compared with the global average of 2.5 ton/ha, mainly due to recurrent droughts and heat stress. Breeding for drought‐tolerant cultivars is an economic and sustainable mitigation strategy against the current and projected drought stress. Therefore, the objectives of this review were to document the impact of drought stress and the key mitigation strategies under drought‐prone semi‐arid sorghum production systems. The first section of the review highlighted the impact of drought and its mitigation strategies emphasizing on the use of drought‐tolerant cultivars as the best strategy. This is followed by perspectives on aspects of drought‐response mechanisms, breeding methods and complementary technologies for drought tolerance. Integration of the conventional and molecular breeding technologies with rapid generation advancement methods could reduce the breeding cycle and increase the efficiency of deploying new varieties. Information presented in this review will guide agronomists and breeders to develop and deploy drought‐tolerant sorghum cultivars that are adapted to the changing production environments in the semi‐arid regions. [ABSTRACT FROM AUTHOR]

A combining-ability analysis is key to select desirable parents and progenies with enhanced response to selection under water-limited environments. The objective of this study was to determine combining ability for agronomic and physiological traits among distantly related drought-tolerant bread wheat (Triticum aestivum L.) genotypes under well-watered (WW) and terminal-drought (TD) conditions to determine their genetic merit for breeding. Ten heat- and drought-tolerant wheat genotypes were crossed in a half-diallel mating design to generate 45 F1s, which were evaluated under WW and TD moisture regimes in rainout shelter (RS) and greenhouse (GH) environments. The following agronomic traits were assessed: days to 50% maturity (DTM), plant height (PH), spike length (SL), number of productive tillers (TN), spikelets number per spike (SPS), number of grains per spike (GPS), grain yield (GY) and thousand-kernel weight (TKW); and physiological traits (stomatal conductance (SC) and chlorophyll content index (CCI)). Variances attributable to general combining ability (GCA) and specific combining ability (SCA) were significant (p < 0.05) for GY, DTM, PH, SL, SPS, GPS, TKW and CCI. The parental genotypes LM72, LM81 and LM95 with positive and significant GCA effects on GY were selected to make crosses to develop high-yielding wheat genotypes for water-limited environments. Crosses LM71 × LM02, LM71 × LM81, LM82 × LM02, LM82 × LM81, LM22 × LM100, LM22 × LM81 and LM95 × LM22 were selected with positive and significant SCA effects for GY. The selected parents and crosses are valuable genetic resources for breeding and genetic advancement. [ABSTRACT FROM AUTHOR]

• Drought tolerance was assessed among 26 okra genotypes using phenotypic traits • Phenotypic variation was observed among assessed okra genotypes under drought stress condition • Positive correlations were recorded between fresh pod yield with fresh pod length, dry pod weight and number of pods per plant • The study identified genotypes such as LS01, LS06, LS09, LS17, LS18, LS19, LS21, LS22, LS24 and LS26 for production and breeding Genetic variation is fundamental for breeding drought-adapted cultivars with economic traits. The objective of this study was to determine the response of selected okra genotypes to drought stress using yield and yield-related traits to identify and select candidate genotypes for drought tolerance breeding. Twenty-six okra genotypes were evaluated in glasshouse (GH) and field (FLD) environments under drought-stressed (DS) and non-stressed (NS) conditions using a 13 × 2 α lattice design with two replications. Data were collected on the following phenotypic traits: number of branches per plant (NB), plant height (PH), days to maturity (DTM), stem diameter (SD), fresh pod length (FPL), dry pod weight per plant (DPW), dry pod length per plant (DPL), number of seeds per plant (NSP), number of pods per plant (NPP), pod yield per plant (YPP) and anthocyanin (ATY) pigmentation of the stem. Significant (P < 0.05) genotype x testing environment x water condition interaction effects were recorded for most traits allowing for selection of okra genotypes suited for drier conditions. YPP positively and significantly correlated with FPL (r = 0.66; P ≤ 0.001), DPW (r = 0.80; P ≤ 0.001) and NPP (r = 0.58; P ≤ 0.001) under DS condition in the FLD environment. The study identified genotypes with high yield and other desirable phenotypic attributes which are useful genetic resources for future crosses and selection of promising progenies based on combining ability analysis and heritability under water-limited environments. [ABSTRACT FROM AUTHOR]

• Bottle gourd and citron watermelon serve as rootstock for commercial sweet dessert watermelon production and possess novel genes for breeding • Genetic resources of both species remain under-utilized and largely un-explored for commercial product development in sub-Saharan Africa (SSA) • Genetic improvement and development of value-added food and non-food products could ensure conservation, production, processing, commercialization and various enterprise development in SSA • Phenotypic and genetic variation of bottle gourd and citron watermelon genetic resources for economic traits are useful for new cultivar design Bottle gourd (Lagenaria siceraria (Molina) Standl.] and citron watermelon (Citrullus lanatus var. citroides (L.H. Bailey) Mansf. ex Greb.) are amongst the widely grown yet under-researched cucurbits genetic resources in sub-Saharan Africa (SSA). Fresh immature leaves, fruit and seed are used for food and medicinal purposes in the region. Furthermore, both species are used as rootstock and donors of novel genes for commercial production and breeding of sweet dessert watermelon cultivars. Despite their economic value and contribution to food and nutrition security in the region, bottle gourd and citron watermelon genetic resources remain under-utilized and largely un-explored for commercial product development. The objective of this review was to document the unique values of bottle gourd and citron watermelon for genetic improvement and development of value-added food and non-food products, and to highlight regional and global efforts on conservation, production, processing, commercialization and various enterprise development of these important indigenous species. The review discussed on the value of both crops as a rootstock to improve fruit yield and quality of cultivated watermelon. This is followed by important summaries on phenotypic and genetic variation of bottle gourd and citron watermelon genetic resources and implications for new cultivar design. Finally, the review highlighted value-added non-food and food-based products developed based on indigenous knowledge systems in SSA and availability and access to genetic resources of bottle gourd and citron watermelon for breeding, product design and deployment. [ABSTRACT FROM AUTHOR]

• Okra is high-valued vegetable crop serving the food, pharmaceutical, paper and oil industry. • Okra production and productivity in sub-Saharan Africa and globally are hindered by a lack of improved cultivars with drought tolerance. • The extensive phenotypic and genotypic variation in okra genetic resources are useful for cultivar development with enhanced seed and oil yields, and drought tolerance. Okra (Abelmoschus esculentus L. Moench) is high-valued vegetable and oil crop serving the food, pharmaceutical, paper and oil industry. The production of okra in sub-Saharan Africa (SSA) and globally are hindered by a lack of improved cultivars with drought tolerance. Considerable phenotypic and genotypic variation present in okra genetic resources from SSA is useful for cultivar design with enhanced pod and oil yields, and drought tolerance. However, the genetic diversity present in SSA's okra germplasm collection is yet to be explored for breeding targeting economic and horticultural traits. The objective of this review was to document the research progresses on phenotypic and genotypic divergence analysis and drought tolerance breeding of okra to facilitate breeding and conservation. The review presented the diversity of okra for key agronomic, horticultural and physiological traits for ideotype breeding, gene introgression and drought tolerance improvement. This is followed by key summaries on genetic diversity using conventional and genomic tools, and use of genetic variation in selection programs involving drought-adaptive and economic traits. The review serves as a baseline information to guide future okra breeding and cultivar design under water limited environments in SSA or related agro-ecologies. [ABSTRACT FROM AUTHOR]

Combining ability effects for yield related traits can serve as selection criteria to pursue breeding for optimal biomass allocation in wheat (Triticum aestivum). The objective of this paper is to provide information based on a retrospective quantitative genetic analysis on combining ability studies of wheat for yield and yield‐related traits to predict potential genetic gains achievable in improving biomass allocation for drought tolerance and soil carbon storage. The study compares data on the general combining ability and specific combining ability effects of wheat for yield and related traits under optimum and drought stressed conditions from 40 studies around the world. Days to heading (DTH), plant height (PH), number of tillers per plant (TN), kernels per spike (KPS), 1,000‐kernel weight (TKW), shoot biomass (SB), and grain yield (GY) exhibited wide variation for general combining ability (GCA) and specific combining ability effects. Progeny performance increased by 14.30 and 4.04% for SB and GY, respectively, compared with parental values under optimum water conditions. Number of tillers and SB exhibited positive associations with GY (.45 ≤ r ≤.85, p <.05) under both water conditions. Meta effect sizes for drought stress were negative. The highest meta‐effect sizes were calculated for DTH (−4.5) followed by SB (−2.0), whereas KPS (−1.25) had the lowest. The genetic gains for PH, SB, and other yield components showed that divergent crosses involving complementary parents could enhance biomass allocation patterns in wheat. This could be used as a basis for improving biomass allocation to roots. Core Ideas: There is sufficient genetic variation in wheat genotypes for manipulating biomass allocation.The number of kernels per spike is stable under varying moisture conditions.Shoot biomass and grain yield expression are severely confounded by drought.Aboveground traits are important for indirect selection of root traits. [ABSTRACT FROM AUTHOR]

The new generation sweetpotato [Ipomoea batatas L. (Lam.)] varieties are valued as dual-purpose types for food and fodder in the crop-livestock mixed-farming systems in sub-Saharan Africa. The objective of this study was to determine the genetic diversity present among dual-purpose sweetpotato genotypes using simple sequence repeat (SSR) markers and phenotypic traits to identify complementary genotypes for direct production and breeding. Twenty-four sweetpotato genotypes were genotyped using nine selected and highly polymorphic SSR markers and dual-purpose phenotypic traits. The genotypes were field-evaluated using a randomized complete block design with three replications in two representative locations in Rwanda. Genotypes differed significantly (p < 0.05) for dual-purpose traits and other assessed phenotypic traits. Genotype "Ukerewe" had the highest fresh root yield (18.24 t ha−1), followed by genotype '8–1038ʹ (17.63 t ha−1). The top-performing genotypes for fresh vine yield were "Wagabolige" (23 t ha−1) and 'NASPOT13ʹ (21.64 t ha−1). The mean expected heterozygosity value was 0.69, indicating adequate genetic variation in the tested germplasm. Cluster analysis grouped the genotypes into three distinct groups, which aided in the identification of genotypes with high fodder and storage root yields, which were SPK004 and K5132/61 from Group I; 4–160, Ukerewe and RW11-2910 from Group II; and RW11-1860, Wagabolige and 2005–179 from Group III. The identified genotypes should be useful genetic resources for production and development of high-performing dual-purpose sweetpotato cultivars in Rwanda. [ABSTRACT FROM AUTHOR]

Sorghum (Sorghum bicolor [L.] Moench) production has considerable socio-economic values in sub-Saharan Africa for food security and to serve the increased industrial demands due to high population pressure and climate change. However, the production and productivity of the crop are yet to be expounded in Nigeria for economic gains. Therefore, the objective of this study was to present the current opportunities and constraints to sorghum production in Nigeria. A participatory rural appraisal (PRA) study was conducted in three selected sorghum growing zones in northern Nigeria involving 250 farmers. Socio-economic data were collected through surveys and focus group discussions. Sorghum was cultivated mainly by males (80%) who had grade 6-12 level of education (31.3%), with the productive age of 21-45 years (75.7%) and a household family size of below five members (52.3%). Low yielding landrace varieties such as Kaura (37.4%) and Fara-fara (29.3%) were the most widely cultivated types across the study zones due to their good grain quality. The major farmers' preferred traits from a sorghum variety were high yield, drought tolerance and Striga resistance. The study recommends integrated sorghum technology development incorporating the described preferences of the farmers for sustainable production and economic gains of the crop. [ABSTRACT FROM AUTHOR]

Ethiopia is the primary wheat producer in Sub-Saharan Africa (SSA) owing to the suitable agro-ecological conditions. Despite wheats economic potential for food security, the actual yield under smallholder farmers conditions is low due to various production constraints. Thus, the objectives of this study were to assess the present wheat production opportunities and constraints and identify farmer-preferred traits to guide variety design with stem rust-resistance and economic traits in eastern Ethiopia. Data on production constraints and trait preferences were collected using structured questionnaires involving 144 wheat-producing farmers. Wheat rust (reported by 97.3% of respondents), small land size (90.4%) and a lack of improved varieties (75.6%) were identified as the major constraints. About 41.7% of respondents in the West-Hararghe and 27.8% in the East-Hararghe zones did not use crop protection strategies to control rusts. Substantial respondent farmers used cultural practices (18.8%), rust-resistant cultivars (13.2%) or, a combination of these (10.4%) to control rust diseases. The essential farmer preferred traits in a wheat variety were rust resistance, high yield potential and good quality grain for bread making. Therefore, there is a need to breed new varieties with high grain yield and quality and durable rust resistance for sustainable wheat production in eastern Ethiopia. [ABSTRACT FROM AUTHOR]

The production and quality of wheat are affected by abiotic constraints including water stress and soil nutrient deficiencies. It is imperative to develop drought-tolerant wheat varieties with high yield potential and enhanced grain protein content for food security. Silicon (Si) is important for plant growth and development but its role in abiotic stress tolerance has been overlooked in breeding programs. Identifying the underlying functional genes controlling drought tolerance, protein content and grain yield is essential for wheat improvement, especially under drought stress. Silicon uptake is conditioned by several Si transporter genes such as Lsi1, Lsi2 and Lsi6 and aquaporins, which facilitate transport of silicon and water between cells. The objectives of this review are to examine the role of Si in improving plant nutrition and drought tolerance, and to appraise the genetic control of Si uptake and breeding methods for improving Si uptake for drought adaptation and improved grain yield and quality. The review highlights the limited progress made in breeding for drought tolerance in wheat, especially in sub-Sahara Africa where the challenge is prevalent. Limited understanding of the genetic basis for Si uptake and physiology contribute to the limited progress in its exploitation in wheat improvement programs. [ABSTRACT FROM AUTHOR]

In warm-humid ago-ecologies of the world, sorghum [Sorghum bicolor (L.) Moench] production is severely affected by anthracnose disease caused by Colletotrichum sublineolum Henn. New sources of anthracnose resistance should be identified to introgress novel genes into susceptible varieties in resistance breeding programs. The objective of this study was to determine genome-wide association of Diversity Arrays Technology Sequencing (DArTseq) based single nucleotide polymorphisms (SNP) markers and anthracnose resistance genes in diverse sorghum populations for resistance breeding. Three hundred sixty-six sorghum populations were assessed for anthracnose resistance in three seasons in western Ethiopia using artificial inoculation. Data on anthracnose severity and the relative area under the disease progress curve were computed. Furthermore, the test populations were genotyped using SNP markers with DArTseq protocol. Population structure analysis and genome-wide association mapping were undertaken based on 11,643 SNPs with <10% missing data. The evaluated population was grouped into eight distinct genetic clusters. A total of eight significant (P < 0.001) marker-trait associations (MTAs) were detected, explaining 4.86–15.9% of the phenotypic variation for anthracnose resistance. Out of which the four markers were above the cutoff point. The significant MTAs in the assessed sorghum population are useful for marker-assisted selection (MAS) in anthracnose resistance breeding programs and for gene and quantitative trait loci (QTL) mapping. [ABSTRACT FROM AUTHOR]

Genetic diversity is key for breeding population development, hybrid breeding, heterotic grouping and genetic analysis, among others. The objective of this study was to examine genetic interrelationships among elite sorghum genotypes bred for resistance to Striga hermonthica Del. Benth and S. asiatica (L.) Kuntze and compatible with a biological control agent Fusarium oxysporum f. sp. strigae (FOS) against Striga using 22 polymorphic simple sequence repeat (SSR) or microsatellite markers. The number of alleles per locus detected by the markers varied from 2 to 7 with a mean value of 4.23. The polymorphic information content (PIC) of the SSR markers ranged from 0.15 to 0.84 with a mean of 0.57 showing moderate discriminatory power of the primers. The neighbour-joining clustering algorithm classified the genotypes into three main groups, revealing narrow to moderate variations existing among the test genotypes. Overall, the genetic diversity revealed by the study will be useful for designed crosses and pyramiding of broad-based resistance genes to control Striga for sustainable sorghum production. [ABSTRACT FROM AUTHOR]

Profiling the genetic composition and relationships among groundnut germplasm collections is essential for the breeding of new cultivars. The objectives of this study were to assess the genetic diversity and population structure among 100 improved groundnut genotypes using agronomic traits and high-density single nucleotide polymorphism (SNP) markers. The genotypes were evaluated for agronomic traits and drought tolerance at the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT)/India across two seasons. Ninety-nine of the test genotypes were profiled with 16363 SNP markers. Pod yield per plant (PY), seed yield per plant (SY), and harvest index (HI) were significantly (p < 0.05) affected by genotype × environment interaction effects. Genotypes ICGV 07222, ICGV 06040, ICGV 01260, ICGV 15083, ICGV 10143, ICGV 03042, ICGV 06039, ICGV 14001, ICGV 11380, and ICGV 13200 ranked top in terms of pod yield under both drought-stressed and optimum conditions. PY exhibited a significant (p ≤ 0.05) correlation with SY, HI, and total biomass (TBM) under both test conditions. Based on the principal component (PC) analysis, PY, SY, HSW, shelling percentage (SHP), and HI were allocated in PC 1 and contributed to the maximum variability for yield under the two water regimes. Hence, selecting these traits could be successful for screening groundnut genotypes under drought-stressed and optimum conditions. The model-based population structure analysis grouped the studied genotypes into three sub-populations. Dendrogram for phenotypic and genotypic also grouped the studied 99 genotypes into three heterogeneous clusters. Analysis of molecular variance revealed that 98% of the total genetic variation was attributed to individuals, while only 2% of the total variance was due to variation among the subspecies. The genetic distance between the Spanish bunch and Virginia bunch types ranged from 0.11 to 0.52. The genotypes ICGV 13189, ICGV 95111, ICGV 14421, and ICGV 171007 were selected for further breeding based on their wide genetic divergence. Data presented in this study will guide groundnut cultivar development emphasizing economic traits and adaptation to water-limited agro-ecologies, including in Ethiopia. [ABSTRACT FROM AUTHOR]

Genetic advancement and gains in yield and related traits are dependent on the selection of best combiner parents and progenies under the prevailing growing conditions. This study was conducted to determine the combining ability effects of eight selected drought-tolerant groundnut parental lines and their F2 progenies under drought-stressed (DS) and non-stressed (NS) conditions to determine the gene actions involved in the inheritance of the studied traits and identify the best parents and progenies for further improvement of the crop for moisture stress tolerance. Experiments were conducted at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) in India during 2020 cropping season. Data on some of the important physiological, yield and yield component traits were collected. The general combining ability (GCA) effects of parents were significant (P < 0.05) for all assessed traits under all testing conditions, except for PB under DS and NS conditions in the glasshouse. The specific combining ability (SCA) effects of progenies were significant (P < 0.05) for all traits, except for PH across all testing environments and PB under field conditions. The genotype ICGV 10178 was the best general combiner with positive contribution and significance to SCMR, PY, SHP, KY, TBM and HI and reduced SLA. Crosses ICGV 10178 × ICGV 11369, ICGV 10373 × ICGV 15083, ICGV 98412 × ICGV 15094 and ICGV 10178 × ICGV 98412 were the best specific combiners for enhanced pod yield and drought tolerance. The GCA was found predominant over the SCA effect for the inheritance of PY, KY and TBM. Higher GCA: SCA rations were recorded for PY and KY under both DS and NS conditions, and SCMR, SLA and TBM under DS condition suggesting the predominant role of additive genes conditioning the inheritance of these traits. Therefore, the above new progenies are useful populations for developing improved pure line groundnut varieties with high pod yield and drought tolerance. [ABSTRACT FROM AUTHOR]

The present study estimated variance components, heritability and genetic advance of phenotypic traits in citron watermelon to guide selection of superior genotypes for direct production and breeding. Thirty‐six citron watermelon landrace accessions were evaluated across two seasons using a 6 × 6 alpha lattice design with three replications. High broad‐sense heritability and genetic advance as per cent of the mean were recorded for fruit length at 83.86% and 4730.45%, seed length (77.73% and 1731.27%), hundred seed weight (73.73% and 4027.36%), fruit diameter (70.44% and 2949.64%) and fruit weight (70.39% and 8490.05%), respectively. Step‐wise regression analysis revealed marketable fruit yield (Myld) and total number of fruits per plant (TNFr) explained 89% (R2 =.89) of total variation for total fruit yield per plant (TFYld), whereas number of seed per fruit (NSPFr) and hundred seed weight (HSW) explained 92% (R2 =.92) of total variation for seed yield per fruit (SYPFr). Citron watermelon landrace accessions WWM03, WWM14, WWM16, WWM39, WWM65, WWM67 and WWM79 with high TFYld and SYPFr were selected for production or breeding. [ABSTRACT FROM AUTHOR]

Sorghum [Sorghum bicolor (L.) Moench] is the main food staple grain widely cultivated in sub-Sharan Africa including Uganda. There is a lack of current information on sorghum production constraints and varietal trait preferences in the major sorghum production areas in Uganda. Therefore, the objective of this study was to assess the sorghum production constraints and farmer preferences for sorghum variety in Uganda. A participatory rural appraisal study was undertaken in four selected sorghum production districts in Uganda (Kumi, Bukedea, Oyam and Gulu). Data were collected through surveys using semi-structured questionnaires and focus group discussion involving 128 and 55 participants, respectively. Data were subjected to parametric and non-parametric statistical analyses to draw inferences. A lack of improved sorghum varieties was the major sorghum production constraint reported by 82.8% of participants. Farmer preferred ideal sorghum varieties were short to medium plant height with high grain yield. The quality attributes mostly preferred by farmers were baking quality, nutrition, and seed colour. Farmers in the study areas mainly grew unimproved sorghum varieties with low food values. Overall, the study provides the current evidence on sorghum production constraints and farmer-preferred attributes that will guide sorghum nutritional quality breeding with farmer preferred traits. [ABSTRACT FROM AUTHOR]

Groundnut rust caused by Puccinia arachidis Speg. is a major cause of yield and quality losses in groundnut (Arachis hypogaea L.) in the warm-humid tropics including Tanzania. Breeding and deployment of rust resistant cultivars with farmer-preferred attributes will bolster groundnut production and productivity. The objective of this study was to determine the combining ability effects and gene action controlling rust resistance in groundnut genotypes for breeding. Twelve selected and complementary parental lines were crossed in a diallel design, to develop F1 progenies, which were advanced to the F2 for individual plant selection. Thirty-three successful partial crosses and the 12 parents were field evaluated using a 5 × 9 alpha lattice designs with two replications over two seasons in Tanzania. The tested genotypes exhibited significant (P < 0.05) variation for rust resistance, yield and yield-related traits. There existed significant (P < 0.05) difference on the general combining ability (GCA) effect of parents and the specific combining ability (SCA) effect of progeny for the assessed traits indicating that both additive and non-additive gene effects conditioned trait inheritance. The Bakers' ratios indicated that the non-additive gene effects predominantly controlling rust resistance and yield components. This suggested that transgressive segregants could be selected for improved rust resistance and yield gains in the advanced pure line generations. Genotypes ICGV-SM 05570 and ICGV-SM 15567 were the best general combiners for rust resistance and grain yield. The crosses ICGV-SM 16589 × Narinut and ICGV-SM 15557 × ICGV-SM 15559 were identified as the best specific combiners for rust resistance with moderate yield levels and medium maturity. Genotypes with desirable GCA or SCA effects were selected for further breeding. [ABSTRACT FROM AUTHOR]