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Information on the general combining ability of inbred lines and the specific combining ability of hybrid combinations is crucial for successful hybrid development. The objectives of this study were to (i) determine the combining ability of thirty selected early maturing maize inbred lines under Striga-infested and optimal environments, (ii) classify the inbred lines into heterotic groups using the general combining ability effects of multiple traits (HGCAMT) and the single nucleotide polymorphism genetic distance (SNP- GD) methods, and (iii) assess the effectiveness of the heterotic grouping methods. One hundred and fifty single-cross hybrids were generated from the thirty inbred lines using the North Carolina Design II mating method. The hybrids and six local check varieties were tested across optimal and Striga-infested environments in Ghana and Nigeria in 2016 and 2017. The inheritance of grain yield was controlled by the non-additive gene action under both environments and the additive gene action across the two research environments. The non-additive gene action modulated the inheritance of measured traits under Striga-infested environments, except for the Striga damage syndrome rating at 8 weeks after planting. Maternal effects were observed for most traits in each environment and across environments. The inbred lines TZEI 127 and TZEI 40 exhibited significant and positive GCA male and female effects for grain yield under each environment and across the two research environments, indicating the presence of favorable alleles for yield improvements. The SNP-GD heterotic grouping method was identified as the most adequate in grouping the thirty inbred lines.

The adoption of new and high yielding pearl millet (Pennisetum glaucum (L.) R. Br.) varieties can be boosted if they correspond to farmers’ preferences and answer the constraints prevailing in the production environments. Therefore, the focus of this study was to assess production constraints, farmers’ preferences and choices of varieties among pearl millet cultivating farmers using participatory rural appraisal (PRA) in the guinea savanna agro-ecological zone of Ghana where the crop is grown. Data collection was through mixed methods of focus group discussion (FGD) and individual interviews with 295 (45 for FGD and 250 for individual interviews) farmers covering 45 communities. Results indicated that the major constraints of production included low yields, bird damage, poor soils, erratic rainfall, downy mildew disease, head insects, and early maturity. Majority of pearl millet farmers depend on own seed source due to lack of access to and low knowledge of improved seeds. Breeding for high grain yield, earliness, resistance to downy mildew disease and bird attack varieties were the leading traits of preference that research should focus on. It is therefore anticipated that breeding program would integrate the product profiling proposed in this work for enhance adoption of new pearl millet varieties in Ghana. Key words: Participatory rural appraisal, constraint, pearl millet Guinea savanna, Ghana.

Peanut (Arachis hypogaea L.) yield and financial returns are often low for smallholder farmers in Ghana. Additionally, aflatoxin concentration in foods derived from peanut can be high enough to adversely affect human health. Eight experiments were conducted in 2016 and 2017 in northern Ghana to compare yield, financial returns, pest reaction, and aflatoxin contamination at harvest with traditional farmer versus improved practices. Relative to the farmer practice, the improved practice consisted of weeding one extra time, applying local potassium-based soaps to suppress arthropods and pathogens, and application of either homogenized oyster shells or a commercial blend of fertilizer containing calcium. Each of these field treatments were followed by either drying peanut on the soil surface and storing in traditional poly bags or drying peanut on tarps and storing in hermetically-sealed bags for 4 months. Peanut yield and financial returns were significantly greater when a commercial blend of fertilizer or oyster shells were applied compared to the farmer practice of not applying any fertilizer. Yield and financial returns were greater when a commercial fertilizer blend was applied compared with oyster shells. Severity of early leaf spot [caused by Passalora arachidicola (Hori) U. Braun] and late leaf spot [caused by Nothopassalora personata (Berk. & M.A. Curtis) U. Braun, C. Nakash., Videira & Crous], scarring and penetration of pods by arthropods, and the number of arthropods at harvest were higher for the farmer practice than for either fertility treatment; no difference was noted when comparing across fertility treatments. Less aflatoxin was observed for both improved practices in the field compared with the farmer practice. Drying peanut on tarps resulted in less aflatoxin compared to drying peanut on the ground regardless of treatments in the field. Aflatoxin concentration after storage was similar when comparing post-harvest treatments of drying on soil surface and storing in poly bags vs. drying on tarps and storing in hermetically-sealed bags. These results demonstrate that substantial financial gain can be realized when management in the field is increased compared with the traditional farmer practice. While aflatoxin concentrations differed between the farmer practice and the improved practices at harvest and after drying, these differences did not translate into differences after storage.

Eggplant (Solanum melongena L.) is one of the most important fruit vegetables in the world, with several nutritional and medicinal benefits. However, little is known about the genetic divergence of yield and its related traits. The objective of this study was to explore gene action and heritability of traits to help direct and strengthen breeding programmes, geared towards improving yield of the crop. Six generations (P1, P2, F1, F2, BC1 and BC2) derived from two crosses (SM001-07 x ST004-03 and SM001 x San005-01) of eggplant accessions, were grown in pots in an open field, using Randomised Complete block Design (RCBD). Estimated data indicated that, the additive-dominance model was adequate to demonstrate the genetic variation and its significance in the inheritance of fruit weight, days to flowering and fruit yield traits. Although non-allelic interactions were found in plant height and number of seeds, additive effect was more pronounced in the genetic control of days to flowering and fruit weight; while dominance effect was more important in the control of plant branching and fruit length. Plant height and fruit yield were influenced by complementary gene action. Furthermore, the study revealed low magnitudes of dominance and environmental variances for most traits showing higher heritability values. In view of the diverse gene actions, with additive, dominant and epistasis, playing significant roles in the control of different traits, backcross, recurrent selection or bi parental could be appropriate for advancing the segregating populations to meet the need of yield improvement in both crosses. Key words: Additive, dominance, Epistasis, gene action

Aflatoxin in peanut (Arachis hypogaea L.) and other crops can negatively affect human health, especially in countries where regulatory agencies do not have limits on aflatoxin entering the food supply chain. While considerable research has been conducted addressing aflatoxin contamination in peanut at individual steps in the supply chain, studies that quantify aflatoxin contamination following combinations of interventions to crop management, drying, and storage are limited. Research was conducted during 2016 and 2017 in two villages in southern Ghana to follow aflatoxin contamination along the supply chain and to compare improved practices with traditional farmer practices used by smallholders. The farmer practice of only a single weeding was compared with improved practices during the growing season up to harvest that included applying local soaps to suppress aphids (Aphis gossypii Golver) that transmit peanut rosette virus disease (Umbravirus: Tombusviridaee), one additional weeding, and calcium applied at pegging. The improved practice for drying included placing pods removed from plants onto tarps compared with the traditional practice of drying on the ground. Storing peanut for four months in hermetically-sealed bags was the improved practice compared with storing in traditional poly bags. All improved practices individually resulted in lower aflatoxin contamination as compared to the farmer practices. While aflatoxin levels were very low (

Identification of heterotic groups and efficient testers, which are important prerequisites for the development of outstanding hybrids, has been a major challenge to its success, especially for early and extra‐early germplasm. This study was carried out to (a) identify the most efficient heterotic grouping method for classifying a set of inbred lines and (b) determine the efficiency of testers in classifying inbred lines into heterotic groups. A total of 205 hybrids obtained by crossing 41 inbred lines with five standard testers were evaluated together with five hybrid checks under drought, low soil nitrogen (N), Striga‐infested and optimal environments in Nigeria between 2014 and 2016. The heterotic group's specific and general combining ability (HSGCA) method was more effective in classifying the inbred lines into heterotic groups. Testers TZEI 17 and TZEI 23 were the most efficient across environments and could be invaluable for classifying other lines into heterotic groups and assessing combining ability of maize inbreds. In addition, these testers and heterotic groups represent an invaluable resource for development of outstanding hybrids in sub‐Saharan Africa (SSA).

Suppressing pest populations below economically-damaging levels is an important element of sustainable peanut (Arachis hypogaea L.) production. Peanut farmers and their advisors often approach pest management with similar goals regardless of where they are located. Anticipating pest outbreaks using field history and monitoring pest populations are fundamental to protecting yield and financial investment. Microsoft Excel was used to develop individual risk indices for pests, a composite assessment of risk, and costs of risk mitigation practices for peanut in Argentina, Ghana, India, Malawi, and North Carolina (NC) in the United States (US). Depending on pests and resources available to manage pests, risk tools vary considerably, especially in the context of other crops that are grown in sequence with peanut, cultivars, and chemical inputs. In Argentina, India, and the US where more tools (e.g., mechanization and pesticides) are available, risk indices for a wide array of economically important pests were developed with the assumption that reducing risk to those pests likely will impact peanut yield in a positive manner. In Ghana and Malawi where fewer management tools are available, risks to yield and aflatoxin contamination are presented without risk indices for individual pests. The Microsoft Excel platform can be updated as new and additional information on effectiveness of management practices becomes apparent. Tools can be developed using this platform that are appropriate for their geography, environment, cropping systems, and pest complexes and management inputs that are available. In this article we present examples for the risk tool for each country. Instituto de Patología Vegetal Fil: Jordan, David L. North Carolina State University. Department of Crop and Soil Sciences; Estados Unidos Fil: Buol, Greg S. North Carolina State University. Department of Crop and Soil Sciences; Estados Unidos Fil: Brandenburg, Rick L. North Carolina State University. Department of Entomology and Plant Pathology; Estados Unidos Fil: Reisig, Dominic. North Carolina State University. Department of Entomology and Plant Pathology; Estados Unidos Fil: Nboyine, Jerry. Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; Ghana Fil: Abudulai, Mumuni. Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; Ghana Fil: Oteng-Frimpong, Richard.Council for Scientific and Industrial Research. Savanna Agricultural Research Institute; Ghana Fil: Brandford Mochiah, Moses.Council for Scientific and Industrial Research. Crops Research Institute; Ghana Fil: Asibuo, James Y. Council for Scientific and Industrial Research. Crops Research Institute; Ghana Fil: Arthur, Stephen. Council for Scientific and Industrial Research. Crops Research Institute; Ghana Fil: Paredes, Juan Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); Argentina Fil: Paredes, Juan Andrés. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina Fil: Monguillot, Joaquín Humberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Fitopatología y Modelización Agrícola (UFyMA); Argentina Fil: Monguillot, Joaquín Humberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patología Vegetal; Argentina Fil: Rhoads, James. University of Georgia. Feed the Future Innovation Lab for Peanut; Estados Unidos

Development, testing and selection of superior inbred lines is crucial for the success of a hybrid program targeting Striga-infested and low soil nitrogen (low-N) environments. The practical value of inbred lines is determined by multiple traits, most of which are inter-dependent. The main objective of this study was to identify early maturing inbred lines based on multiple traits under optimal, low-N and Striga-infested environments for hybrid development and population improvement. One hundred early maturing inbred lines were evaluated under artificial Striga-infestation, low-N and optimal growing environments for two years at Kwadaso and Nyankpala in Ghana. The inbred lines exhibited high levels of genetic variability for grain yield and other agronomic traits desirable for Striga resistance and low-N tolerance. Under optimal growing conditions, days to silking (DS), ears per plot (EHARV) and days to anthesis (DA) had high direct effects on grain yield (GYLD). Days to silking and ears per plant (EPP) had the highest positive direct effects on GYLD, while DA had the highest negative direct effect on grain yield in low-N environments. Under Striga-infestation, the highest negative direct effect on GYLD was obtained with EASP. All the measured traits previously identified to have direct influence on grain yield were associated with it and could be used for indirect selection for improved grain yield under the contrasting environments. Forty-eight of the 100 inbred lines studied were identified as low-N tolerant and forty-nine as Striga resistant.

Drought is the most important abiotic limitation to groundnut yields across the world, and the Northern Regions of Ghana. The study estimated the heritability and genetic variability of selected parents of groundnut for drought tolerance traits to aid in their effective selection and utilization. The North Carolina II mating design was adopted while the variance component method was used to estimate heritabilities in the narrow and broad sense as well. Chlorophyll content (greenness of leaves) was recorded at 60 and 80 DAP. The objective was to measure the chlorophyll content and hence the drought tolerance performance of the entries. Mean squares caused by differences among crosses was partitioned into difference due to male parents and female parents, which was attributed to general combining ability (GCA), as well as difference due to male x female interaction, which was attributed to specific combining ability (SCA). Narrow Sense Heritability from the variance components for different traits varied under both water regimes, ranging from 12.2% to 95.7%. The most heritable traits were: dry biomass weight (95.7%), days to 50% flowering (91.0%), seed yield (90.0%), plant height at harvest (76.0%), SCMR 60 DAP (71.7%), days to maturity (67.0%) and SCMR 80 DAP (66.0%). Pod yield (12.3%) and harvest index (12.2%) exhibited low narrow sense heritabilities. Additive gene effects largely controlled the inheritance of pod, seed and biomass yields. Positive association between most yield and yield components as well as higher heritabilities shows that selection for higher yield and maturity is conceivable in improving groundnuts. Key words: Abiotic, constraints, chlorophyll content, drought, genetic, groundnut, heritability, North Carolina II mating design, tolerance, yield.

Groundnut farming has always been an essentially major agricultural venture, both commercially and in subsistence, to the inhabitants of the Northern Regions of Ghana. The current study sought to assess the relationship and genetic diversity, through a phylogenetic analysis, among twenty-five (25) Ghanaian groundnut genotypes, in reference to US groundnut mini-core collection, based on the Kompetitive allele-specific PCR (KASP) protocol (a high throughput genotyping platform for marker-assisted selection, studies [LightCycler 480II]) and axiom single nucleotide polymorphism (SNP) array version 2 (48,000 SNP features). It further sought to classify the groundnuts into sub-species based on botanical types, market types, general uses as well as genetic diversity to late leaf spot resistance. The Qiagen Dneasy DNA extraction Kit was used for DNA extraction. Results of the study indicate that majority of the Ghanaian groundnuts evaluated belonged to the Virginia (hypogaea) (large-seeded), Spanish/Valencia (vulgaris/fastigiata) and Mixed (Virginia x Valencia) types based on characteristics, including growth habit (erect/semi-erect/upright/bunch or trailing/spreading) seed or pod size/shape and disease resistance. Thus, significant genetic diversity in morphological characteristics, botanical and market varieties, growth habit and seed size were found among the groundnuts studied. Information generated from this study can be used to develop new groundnut breeding lines that combine these traits to produce higher yields. Marker-assisted selection procedures could help enhance this process based on the availability of QTLs and genes for the traits and markers developed in that regard. Key words: Axiom, genetic diversity, genotypes, groundnut, Kompetitive allele-specific PCR (KASP), mini-core collection, phylogenetic analysis, disease resistance, single nucleotide polymorphism (SNP).

Six generations of eggplants (P1, P2, F1, F2, BC1 and BC2) obtained from two crosses SM001-07 x ST004-03 and SM001-07 x San005-01 were grown in an open field using Randomized complete Block Design with four replications. The experiment was conducted to determine gene effects for the inheritance of twelve nutritional and antioxidant traits in eggplant using generation mean analysis. The analysis of variance showed significant differences for most traits indicating the presence of sufficient variation in the eggplant materials under study. Additive-dominance effect was adequate to demonstrate the genetic variation and its significance in the inheritance of protein and magnesium contents, while non-allelic interactions were observed to be important for iron, zinc and total phenol in both crosses. The study also showed low values for dominance and environmental variances that resulted in high heritability values for most traits. Therefore, to improve these traits population improvement approaches (recurrent selection or pure line) followed by delayed selection in segregating generation would yield better results.

Testing and identification of high-yielding and stable hybrids adapted to contrasting environments is crucial for sustainable maize (Zea mays L.) production in sub-Saharan Africa. The objectives of this study were to (i) assess the yield response of 150 single-cross hybrids under low soil nitrogen (low-N), Striga-infested and optimal growing environments, and (ii) identify the most suitable environments for the selection of superior and stable hybrids. The 150 hybrids were derived from 30 inbred parents via North Carolina design II mating scheme. They were tested, together with six checks, in a 13 × 12 alpha lattice design with two replications across 10 test environments in 2016 and 2017. Genotype by environment interaction was significant for yield, with high repeatability (0.70) across the test environments. Test environments KWDS-LN-16 and KWDS-OPT-16 were found to be the ideal test environments for selecting superior hybrids. About 62% of the hybrids were stable across environments. Hybrids TZEI 3A × TZdEI 192, TZdEI 216 × TZEI 3A and TZEI 379 × TZdEI 272 were identified as high yielding and most stable across environments. These outstanding hybrids with tolerance to both Striga and low-N should be further tested extensively on-farm for potential release in Ghana and other West African countries.

The study of genetic diversity of any germplasm helps to facilitate its use and management. This experiment was carried out to determine the genetic diversity among 87 rice accessions from six countries. Seventeen quantitative traits were recorded based on the internationally accepted standard evaluation system for rice from IRRI. Analysis of variance, principal component analysis (PCA) and correlation amongst quantitative traits were carried out. Highly significant (P

Plant breeders’ knowledge of precise traits preferred by variety users would accelerate varietal turnover and widen adoption of newly developed maize varieties in Ghana. The objective of this research was to provide empirical evidence of trait preferences of farmers and other actors in the maize value chain in northern Ghana, based on which research strategies for maize improvement could be formulated. Participatory rural appraisal was conducted in 2016 to determine key traits preferred by maize value chain actors across the three regions in northern Ghana. A total of 279 maize value chain actors were interviewed. Different scoring and ranking techniques were used to assess the maize traits preferred by the different actors. Participatory variety selection trials were also conducted in the Tolon, West Gonja, Binduri, and Sissala East districts in northern Ghana from 2014 to 2016. The mother-baby trial approach was used to evaluate eight hybrids with 3000 farmers. Data on yield and agronomic performance of the hybrids and farmer’s selection criteria were collected. Data analyses were performed using GenStat Edition 16 and SPSS Edition 20 statistical packages. The participatory rural appraisal method identified farmers, input dealers, traders, and processors as the primary maize value chain actors in the study areas. Trait preferences of the different actors overlapped and revolved around grain quality including nutritional value, and stress tolerance and grain yield. Results of the participatory variety selection study revealed that across districts, farmers preferred high-yielding varieties with multiple cobs per plant, white grain endosperm color, and bigger and fully filled cobs. For the first time, our holistic assessment of the trait preferences of key actors of the maize value chain in northern Ghana revealed a comprehensive list of traits, which could be used by breeders to develop varieties that may be preferred by all value chain actors in northern Ghana. Supplementary Information The online version contains supplementary material available at 10.1007/s13593-021-00708-w.

The study sought to assess combining ability and establish the gene action involved in the inheritance and heritability of yield and yield components in taro. Five (5) parents and twenty (20) F1 hybrids generated from hybridization were evaluated in 3 locations in Ghana. The field trials were laid in RCBD with three replications. Data measured included number of stolons, number of suckers, corm length (mm), corm width (mm), corm weight (g), yield (kg/ha) and dry matter content. Analysis of variance (ANOVA) was conducted using Statistical Tool for Agricultural Research version 2.0.1. Griffing Method II, Model 1 diallel analysis was used to estimate the general and specific combining ability. Heterosis was estimated for all the F1 hybrids. Heritability and correlation among the traits was also estimated. The ANOVA revealed significant differences among the genotypes for yield and its components. The high magnitude of SCA over GCA, high broad sense heritability over narrow sense heritability and below unity Bakers ratio observed for most of the yield traits studied indicates the predominance of non-additive gene action in the expression of the traits. The highly significant positive heterosis and above parental means recorded for the progenies indicates that effective progress can be made in the development of high yielding varieties of taro. CE/IND/16 which recorded significant positive GCA for all the traits except for number of stolons can be included in hybridization programs for varietal development in taro. Hybrids: CE/MAL/32 $$\times $$ KAO19, KAO19 $$\times $$ CE/IND/16, CE/IND/16 $$\times $$ KAO19 and CE/IND/16 $$\times $$ BL/SM/10 which had high hybrid vigor across the research environments could be further evaluated in other environments to ascertain their potentials for release to farmers for cultivation. Significant positive association observed between corm weight and yield/ha(kg) and corm width (mm), indicates that breeding for high corm weight and corm width will definitely improve the yield of taro.

Anther indehiscence in certain wide crosses combines male sterility with stigma exertion, a phenomenon that is desirable for hybrid rice seed production. This study sought to identify chromosomal region(s) that combine anther indehiscence with exerted stigmas. A mapping population consisting of 189 BC1F1 plants was derived from a cross between CRI-48 and Jasmine 85 and backcrossing the resulting F1 to Jasmine 85. Contrary to the three complementary genes mode of inheritance reported earlier, a single locus (AI6-1) was mapped on chromosome 6 at 27.4 cM for anther indehiscence with exerted stigmas through a mixed model-based composite interval mapping (MCIM). This locus was flanked by two single nucleotide polymorphism (SNP) markers, K_ID6002884 and K_ID6003341 within a range of 23.1-28.9 cM. The allele at the locus was contributed by the CRI-48 parent which has Oryza glaberrima ancestry. This locus is suggested to control anther indehiscence and stigma exertion through pleiotropic gene action or cluster of genes.

The African oil palm (Elaeis guineensis. Jacq.) is an oleaginous tree belonging to the family Arecaceae. The crop is naturally a diploid species (2n = 2x = 32) and the most important oil bearing perennial tree crop cultivated in tropics. In spite of its huge economic importance, it has a very narrow genetic base making its improvement using conventional techniques very difficult. All commercial planting materials are hybrids derived from heterozygous pisifera and dura parents. The imperativeness of generating adequate novel materials with sufficient genetic diversity in order to increase progress in oil palm improvement is therefore, very essential. Genomic manipulations through chromosome doubling may present opportunities to broaden the genetic base and increase the diversity within the commercial oil palm species. Developing an efficient genome doubling protocols using anti-mitotic agents is very important in this respect. It will also complement haploid/doubled haploid production efforts by enabling successful deployment of doubled haploids in oil palm breeding programmes. The objectives of this study were, therefore, to optimize genomic doubling in oil palm by determining optimum colchicine concentrations and also outline procedures for screening for putative polyploids. Oil palm seedlings were subjected to colchicine treatment at concentrations of 0, 1.26, 3.76, 6.26 and 8.76 mM for 0, 3, 6, 12 or 24 hours. The colchicine treatment produced variable physio-morphologies in the treated seedlings. Principal component analysis and agglomerative hierarchical clustering of genotype dependent treatments were carried out to provide an ordination guide. The response of oil palm seedlings to colchicine treatment showed genotypic, concentration of colchicine applied and treatment duration dependency. Ploidy level analysis of the colchicine treated seedlings revealed that polyploidization in oil palm increased significantly (p ≤ 0.05) with increasing colchicine concentration. Seedlings of the genotype G-131 responded more favourably to the colchicine treatment than seedlings of G-132. Optimal colchicine concentration for genome doubling in G-131 (28.9 %) and G-132 (17.8 %) was 8.76 mM applied for a period of 24 h. A population of 154 tetraploids out of 1800 seedlings of the two genotypes mutagenized has been identified and being raised for further evaluation and genetic exploitation.

Twenty-two open-pollinated varieties (OPVs) of pearl millet (Pennisetum glaucum) genotypes were tested in two locations for three seasons in Ghana to estimate the magnitude of genetic variability, heritability, and stability for grain yield and related traits and grain micronutrients among the varieties. General analysis of variance within and across locations and years revealed very highly significant variability ( p < 0.01 ) among the genotypes. The additive main effects and multiplicative interaction (AMMI) analyses revealed significant genotype × environment interaction (GEI) that influenced the relative ranking of genotypes across the environments. Genotypic variance ( σ 2 g ) contributed a greater proportion of the phenotypic variance (σ2p) for plant height (530.31) and grain Fe content (34.72). Broad-sense heritability ( h b s 2 ) varied widely from 24.82% for grain yield to 77.53% in days to flower. Phenotypic coefficient of variation (PCV) was higher than genotypic coefficient of variation (GCV) for all traits, indicating strong play of environment on trait expressions. 11 out of the 22 OPVs were stable for grain yield and micronutrients across environments for the three-year period and included GB 8735 and ICMV 221 Wbr and SOSAT-C88.

Cassava (Manihot esculentaCrantz) is an important industrial and staple crop due to its high starch content, low input requirement, and resilience which makes it an ideal crop for sustainable agricultural systems and marginal lands in the tropics. However, the lack of genomic information on local genetic resources has impeded efficient conservation and improvement of the crop and the exploration of its full agronomic and breeding potential. This work was carried out to obtain information on population structure and extent of genetic variability among some local landraces conserved at the Plant Genetic Resources Research Institute, Ghana and exotic cassava accessions with Diversity Array Technology based SilicoDArT and SNP markers to infer how the relatedness in the genetic materials can be used to enhance germplasm curation and future breeding efforts. A total of 10521 SilicoDArT and 10808 SNP markers were used with varying polymorphic information content (PIC) values. The average PIC was 0.36 and 0.28 for the SilicoDArT and SNPs respectively. Population structure and average linkage hierarchical clustering based on SNPs revealed two distinct subpopulations and a large number of admixtures. Both DArT platforms identified 22 landraces as potential duplicates based on Gower’s genetic dissimilarity. The expected heterozygosity which defines the genetic variation within each subpopulation was 0.008 for subpop1 which were mainly landraces and 0.391 for subpop2 indicating the homogeneous and admixture nature of the two subpopulations. Further analysis upon removal of the duplicates increased the expected heterozygosity of subpop1 from 0.008 to 0.357. A mantel test indicated strong interdependence (r = 0.970; P < 0.001) between SilicoDArT and DArTSeq SNP genotypic data suggesting both marker platforms as a robust system for genomic studies in cassava. These findings provide important information for efficientex-situconservation of cassava, future heterosis breeding, and marker-assisted selection (MAS) to enhance cassava improvement.

Salt stress is a menace to rice production and a threat to food security worldwide. We evaluated 308 F4 families from Sahel 317/Madina Koyo for tolerance to salt stress at the early seedling stage. To better understand genomic regions controlling tolerance in the population, we genotyped the progenies and the two parents using single nucleotide polymorphism (SNP) markers and regressed the genotypic data on their phenotype to detect QTLs. An average reduction of 63.4% was observed for all fitness-related traits among the F4 families. A total of 46 progenies recorded an average salt injury score (SIS) between 1–3 and were rated as tolerant to salt stress at the early seedling stage. A high-density genetic map was constructed for the 12 rice chromosomes using 3698 SNP markers. Multiple interval mapping identified 13 QTLs for SIS, shoot length, shoot dry weight and root length on chromosomes 2, 3, 4, 6, 7, 10 and 12, with trait increasing alleles coming from both parents. Two (qSDW2 and qRL2.2) and three (qSL2, qRL2.1 and qSIS2) QTLs at different regions on chromosome 2 and another two on chromosome 7 (qSDW7 and qSL7) were tightly linked. These QTLs could facilitate breeding for salt tolerance at the early seedling stage as direct selection for one, would mean indirectly selecting for the other. Fine mapping of these novel QTLs in a different genetic background is necessary to confirm their stability and usefulness in breeding for tolerance to salinity in rice.

Anther indehiscence in certain wide crosses combines male sterility with stigma exertion, a phenomenon that is desirable for hybrid rice seed production. This study sought to identify chromosomal region(s) that combine anther indehiscence with exerted stigmas. A mapping population consisting of 189 BC1F1 plants was derived from a cross between CRI-48 and Jasmine 85 and backcrossing the resulting F1 to Jasmine 85. Contrary to the three complementary genes mode of inheritance reported earlier, a single locus (AI6-1) was mapped on chromosome 6 at 27.4 cM for anther indehiscence with exerted stigmas through a mixed model-based composite interval mapping (MCIM). This locus was flanked by two single nucleotide polymorphism (SNP) markers, K_ID6002884 and K_ID6003341 within a range of 23.1–28.9 cM. The allele at the locus was contributed by the CRI-48 parent which has Oryza glaberrima ancestry. This locus is suggested to control anther indehiscence and stigma exertion through pleiotropic gene action or cluster of genes., Outcrossing, genetic mapping, hybrid rice seed production, SNP markers, pleiotropic gene action.

Aflatoxin in peanut ( Arachis hypogaea L.) and other crops can negatively affect human health, especially in countries where regulatory agencies do not have limits on aflatoxin entering the food supply chain. While considerable research has been conducted addressing aflatoxin contamination in peanut at individual steps in the supply chain, studies that quantify aflatoxin contamination following combinations of interventions of crop management, drying, and storage are limited. Research was conducted during 2016 and 2017 in two villages in southern Ghana to follow aflatoxin contamination along the supply chain and to compare improved practices with traditional farmer practices used by smallholders. The farmer practice of only a single weeding was compared with improved practices during the growing season up to harvest that included applying local soaps to suppress aphids ( Aphis gossypii Golver) that transmit peanut rosette virus disease ( Umbravirus: Tombusviridae e), one additional weeding, and calcium applied at pegging. The improved practice for drying included placing pods removed from plants onto tarps compared with the traditional practice of drying on the ground. Storing peanut for four months in hermetically-sealed bags was the improved practice compared with storing in traditional poly bags. All improved practices individually resulted in less aflatoxin contamination as compared to the farmer practices. While aflatoxin levels were found to be very low (

Erratic rainfall is often a limiting factor in the semi-arid regions where most groundnut cultivation occurs. As a result, ensuring availability of cultivars that possess inherent tolerance to drought stress has become a priority. Field and box (wooden boxes of 2 m length × 1 m width × 0.3 m depth) experiments were conducted under drought and non-drought conditions to identify physiological and agronomic traits correlated with pod yield (PY). Fifty (50) advanced breeding lines were evaluated. Linear models containing different combinations of total dry matter at maturity, crop growth rate, pod growth rate, partition coefficient, and harvest index were able to predict PY under intermittent drought (adjusted R2 range: 0.9798–0.9895). The box experiment was more discriminating of genotypes than field experiments, making it a suitable technique for drought tolerance screening using specific leaf area and leaf chlorophyll content. As a result, screening and pre-selection using the seed-box technique be...

Rice is an important staple food crop that feeds over half of the global population and has become the cereal that provides a major source of calories for the urban and rural poor in Africa. This work aimed to evaluate the morphological of rice (Oryza sativa and Oryza glaberrima) germplasm. In the present study, 14 quantitative traits were used across 48 accessions or genotypes obtained from Central Agricultural Research Institute (CARI), Liberia and Plant Genetic Resources Research Institute (PGRRI), Ghana. In this research, Completely Randomized Design was conducted to study the genetic variability among the 48 genotypes or accessions obtained from CARI, Liberia and PGRRI, Ghana. Field data taken included 14 quantitative traits scored using the IRRI descriptor list. Analysis of variance revealed highly significant difference (P≤ 0.01) among the accessions for all quantitative traits studied. Four significant principal components analysis were identified and accounted for 55.3%. PC1 had Eigen-value of 18.5%, whereas PC2 accounted for Eigen-value of 14.5%. PC3 contributed 12.2% whereas PC4 had 10.1%. Correlation analysis indicated the length of ligule was highly significant and positive leaf width blade. Similar observation was made with grain length and length of ligule. Some accessions in the biplot showed longer vector distances, while shorter vector distances were observed referencing PC1; Gh1578 recorded the longest vector distances while Gh1526 and LAC 23-1, recorded the moderate distances from the vector origin at the similarity coefficients at 90%. The highly distant genetic diversity was found between ACSS37 and ACSS1 from Ghana and Liberia. Cluster X was the largest of all the clusters while Clusters VII and VIII were the second largest clusters with seven accessions each. The outcome of this study should be useful for the management of the germplasm conservation and future rice genetic improvement. However, all the accessions may be cultivated over time at different locations on the field to ascertain their stability and purity. Key words: Correlation, morphological, quantitative, qualitative, accessions.

Wild relatives of eggplants represent a good source of variation for breeding programmes, in particular for traits related to biotic and abiotic stresses and also fruit quality traits. However, wild species remain largely unexploited for eggplant breeding compared to other crops like tomato. Seven cultivated eggplant accessions (SM001-02, SM001-04, SM001-06, SM001-07, SA002-02, SA002-03 and SMA003-03) were crossed with three wild accessions (ST004-03 (Solanum tovum), San005-01 (Solanum anguivi) and SA002-08 (Solanum aethiopicum)) in an open field using completely randomized design. The success of fruit and seed set as well as seed germination depended on the cross combination and the direction of the cross. In this regard, no fruit set was recorded when the wild accessions were used as female parents. The highest fruit set and mean number of seeds/fruit was obtained from the crosses Sm001-07 × ST004-03 (6%; 264 seeds) and Sm001-07 × San005-01 (5.7%, 114 seeds), respectively. The germination of hybrid seeds was recorded in only three crosses, SM001-07 × ST004-03, SM001-07 × San005-01 and SA002-02 × San005-01 with germination range from 3.3 to 16.6%. However, plantlets from these seeds did not survive after two weeks of germination. The hybridity of the putative interspecific F1 hybrids (through tissue culture) was confirmed with a morphological marker. These hybrids obtained will contribute to broadening the genetic background of cultivated eggplant species used in this study and to the genetic enhancement of this crop. Key words: Crossability, eggplant, fruit set, germination, introgression, seed set, wild relatives.

Maize is an important cereal crop in sub-Saharan Africa but production is adversely affected by maize streak virus disease (MSVD). In Ghana, re-occurrence of the disease has been reported in several regions, therefore, necessitating the development of resistant hybrids as the most sustainable and economical option. The objectives of the study were to identify parents and hybrids that combine MSVD resistance with high yield and determine the influence of maternal effect on the inheritance of MSVD resistance. To achieve these, five parental inbred lines namely: TZEI-4, TZEI-7, TZEI-22, TZEI-31 and TZEI-157 were crossed in a full diallel mating design during the major season of 2015. The resulting F1 hybrids were evaluated under natural and artificial infestations during the minor and major seasons of 2015/2016 using 9 x 3 alpha-lattice design with three replications. General combining ability (GCA) and specific combining ability (SCA) mean squares were significant for MSVD severity mean score and only SCA for grain yield. Additive gene effect was preponderant for MSVD severity mean score, whereas grain yield was influenced by non-additive gene effect. Maternal effect had no significant contribution to the inheritance of MSVD resistance. GCA by environment and SCA by environment mean squares were significant for MSVD severity mean score. GCA effects revealed that inbreds TZEI-7 and TZEI-22 were resistant to MSVD. They could be good combiners for grain yield in addition to TZEI-31 and TZEI-157. Hybrids TZEI-4*TZEI-22 and TZEI-4*TZEI-31 showed resistance to MSVD as revealed by their SCA effects and heterotic values. TZEI-7*TZEI-157, TZEI-31*TZEI-157, TZEI-22*TZEI-157 and TZEI-4*TZEI-22 had positive and significant SCA effect, mid-parent heterosis and high parent heterosis for grain yield. Promising hybrids TZEI-4*TZEI-22, TZEI-22*TZEI-157, TZEI-7*TZEI-157 and TZEI-31*TZEI-157 identified in this study should be further tested in multi-locations across Ghana to determine their stability and adaptability. Key words: Maize streak virus disease, grain yield, resistance, full diallel, general combining ability, specific combining ability.

Cowpea is an important warm-season grain legume primarily found in the semi-arid tropics. It is mostly cultivated by subsistence farmers in West and Central, sub-Saharan Africa, where its grains and leaves are used mainly as food. Its productivity is challenged by several biotic and abiotic factors. A major biotic constraint in cowpea production is the parasitic weed Striga gesnerioides. This study was to assess three molecular markers (SSR-1, 61RM2 and C42-4B) and their abilities to identify resistance and susceptibility of F2 cowpea progenies to S. gesnerioides. To determine the genetic diversity among parental lines and progenies based on markers associated with Striga resistance. A total of 93 F2 progenies from a cross between IT99K-573-1-1 and Hewale were screened. The results showed that the three markers had discriminating power to distinguish between resistant and susceptible genotypes. Marker SSR-1 was found in 61 F2 individuals suggesting that the resistant alleles were highly repeatable within the population. Marker C42-2B was found in 58 F2 individuals while marker 61RM2 was also found in 68 F2 individuals. Allele frequency yielded by the three markers ranged from 0.62 to 0.73 with the mean of 0.67. Genetic diversity range from 0.39 to 0.42 with the mean of 0.43. Polymorphic Information Content (PIC) ranged from 0.32 to 0.36 with the mean of 0.34. The results obtained from these findings indicated that these markers would facilitate and shorten the breeding time as the markers can be used to screen lines or accessions two weeks after planting.

Rice is an important staple food crop that feeds over half of the global population and it has become the cereal that provides a major source of calories for the urban and rural poor in Africa. This research aimed to use simple sequence repeat (SSR) markers to evaluate the genetic diversity in rice (Oryza sativa and Oryza glaberrima) germplasm as breeding method. In the present study, 16 SSR markers were used across 48 genotypes or accessions obtained from Central Agricultural Research Institute (CARI), Suakoko, Liberia and Plant Genetic Resources Research Institute (PGRRI), Bunso, Ghana. DNA was extracted from 48 plants per accession without bulking to check the purity of the accession using the 16 SSR markers. Sixteen primers were acquired out of 20 primers which showed DNA amplification and polymorphism among the 48 rice accessions. The numbers of alleles detected by these 16 primers ranged from 1 to 16 with a mean of 5.25, while polymorphism information content (PIC) ranged from 0.06 to 0.66 with a mean of 0.35. The SSR markers were highly informative as generated by the power marker V3.25 software. The unweight pair group method with arithmetic averages (UPGMA) cluster dendrogram generated based on the 16 SSR markers grouped the accessions into 11 main clusters. At the similarity coefficients of 90%, the highly distance genetic diversity was found between 2 accessions; ACSS37 and ACSS1. Cluster X was the largest of all the clusters, while clusters VII and VIII were the second largest clusters with 7 accessions each. The outcome of this study should be useful to manage the gremplasm conservation and future rice genetic improvement. Key words: Germplasm, genetic diversity, molecular markers, polymorphism, sequence repeat.

Groundnut yield is constrained in most cases by early and lateleaf spots diseases. Selection and breeding for resistance will enhance yields. Therefore, this study was conducted in Crop Research Institute, Fumesua-Kumasi, Ghana to screen 20 groundnut varieties for leaf spots resistance using both molecular and phenotypic tools. Differences in disease incidence among individual plants, severity score, lesion diameter and defoliation across the 20 genotypes were highly significant (p

Availability of multiple-stress tolerant maize is critical for improvement in maize production in West and Central Africa (WCA). A study was carried out to (i) assess a set of inbred lines for combining ability under stressed and optimal conditions, (ii) determine the performance of the testcrosses under different conditions, and (iii) identify outstanding hybrids across the conditions. Two hundred and five testcrosses were planted with five hybrid checks under Striga-infested, low soil nitrogen, drought and optimal conditions between 2015 and 2016 in Nigeria. The grain yield inheritance under optimal condition was largely regulated by additive gene effect whereas non-additive gene effects largely regulated grain yield under the three stresses. Four of the inbreds had significant positive general combining ability effects each under low N and drought, and three under Striga infestation for grain yield. The inbreds could be vital sources of beneficial alleles for development and improvement of tropical yellow maize hybrids and populations. Hybrids TZEI 443 x ENT 13 and TZEI 462 x TZEI 10 were high yielding and stable; they out-performed the three early maturing released hybrids in WCA. The new hybrids should be extensively assessed and released in the sub-region to improve food security.