Abstract
Cowpea is a nutrient-dense legume that significantly contributes to the population’s diet in sub-Saharan Africa and other regions of the world. Improving cowpea cultivars to be more resilient to abiotic stress such as drought would be of great importance. The use of a multi-parent advanced generation intercross (MAGIC) population has been shown to be efficient in increasing the frequency of rare alleles that could be associated with important agricultural traits. In addition, drought tolerance index has been reported to be a reliable parameter for assessing crop tolerance to water-deficit conditions. Therefore, the objectives of this study were to evaluate the drought tolerance index for plant growth habit, plant maturity, flowering time, 100-seed weight, and grain yield in a MAGIC cowpea population, to conduct genome-wide association study (GWAS) and identify single nucleotide polymorphism (SNP) markers associated with the drought tolerance indices, to investigate the potential relationship existing between the significant loci associated with the drought tolerance indices, and to conduct genomic selection (GS). These analyses were performed using the existing phenotypic and genotypic data published for the MAGIC population which consisted of 305 F8 recombinant inbred lines (RILs) developed at University of California, Riverside. The results indicated that: (1) large variation in drought tolerance indices existed among the cowpea genotypes, (2) a total of 14, 18, 5, 5, and 35 SNPs were associated with plant growth habit change due to drought stress, and drought tolerance indices for maturity, flowering time, 100-seed weight, and grain yield, respectively, (3) the network-guided approach revealed clear interactions between the loci associated with the drought tolerance traits, and (4) the GS accuracy varied from low to moderate. These results could be applied to improve drought tolerance in cowpea through marker-assisted selection (MAS) and genomic selection (GS). To the best of our knowledge, this is the first report on marker loci associated with drought tolerance indices in cowpea.
Highlights
Cowpea [Vigna unguiculata (L.) Walp.] is a diploid legume (2n = 2x = 22) grown for its relatively high amount of seed protein[1]
A tolerance index greater than 100 for plant maturity indicated that restricted irrigation made plant maturity longer, whereas a tolerance index lower than 100 suggested plant maturity being shorter due to water deficit
A large variation in tolerance index for maturity was identified among the recombinant inbred lines (RILs)
Summary
Cowpea [Vigna unguiculata (L.) Walp.] is a diploid legume (2n = 2x = 22) grown for its relatively high amount of seed protein[1]. Cowpea cultivation exists in Asia, Oceania, the Middle East, southern Europe, Africa, 510.0 phosphorus, and 1430.0 potassium, in mg per 100-g seed (Frota et al.[3]). Cowpea consumption has proven to promote health due to the high amount of antioxidants found in cowpea seeds[4,5]. In addition to grain nutritional values, cowpea biomass can be used for animal feed and cover–crop production[6]. Cowpea was grown on more than 11 million hectares worldwide, and over 70% of that. The United States has the greatest potential for exporting cowpea with the highest average cowpea yield per hectare[8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
