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Cowpea is an important food and nutritional security grain legume crop in the semi-arid regions of sub-Saharan Africa. Its production is limited by biotic factors including pre-harvest insect pests such as aphids. Aphids cause yield reductions, promotes the growth of sooty moulds, honeydew and as a result reduce photosynthetic processes and rates. Various methods have been deployed to try to control the damage of aphids in cowpea plants. The methods include the use of chemical insecticides, cultural, mechanical, biological controls and integrated pest management. However, these methods have not been very effective as smallholder farmers growing cowpea in marginal areas cannot afford them. Hence, host plant resistance/genetic control is the best and effective method for controlling aphids in cowpea plantations. Breeding for aphid resistance is one of the effective methods that can sustain the production and productivity of the cowpea for longer periods. Furthermore, assessing the presence of genetic diversity can also help in sourcing genes of novelty for addressing this important issue to increase the production and productivity of the crop. Recently, scientists have used various strategies to try to solve the challenge of aphid damage on cowpea. The objective of this review was to document the research progresses on aphid resistance breeding of cowpea to facilitate the breeding and conservation of cowpea germplasm. The review serves as a baseline information to guide future cowpea breeding for resistance to aphids. [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]

• 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]

• 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]