2018 ASHS Annual Conference

Cowpea (Vigna unguiculata (L.) Walp) is a legume which is widely cultivated in tropical and semi-arid areas. It provides affordable nutritional food for human and is used to feed livestock. Previous investigations reported that cowpea aphid (Aphis craccivora) and cowpea mosaic virus (CPMV) unfavorably affect cowpea production. Phenotyping for resistance to aphids and cowpea mosaic virus could be challenging, time-consuming, and labor intensive, which could slow down the breeding process. Fortunately, this can be addressed by using a genomic selection approach which aims at predicting phenotypes using the information from the genotypes. Therefore, the objective of this study will be to conduct a genomic selection study and to determine the accuracy of genomic estimated breeding values for resistance to aphids and cowpea mosaic virus resistance in cowpea. A total of 333 and 338 cowpea accessions were phenotyped for resistance cowpea aphids and cowpea mosaic virus, respectively. Each association panel will be divided into subsets of training and testing populations using R. Genomic selection will be also conducted in R using rrBLUP, Bayes A, Bayes B, and LASSO. Genomic selection will be performed using a ten-cross fold validation approach. Effects of a total of at least 1000 SNPs will be computed. We expect that: 1) genomic selection accuracy will range from low to moderate, 2) higher accuracy will be obtained using Bayes B, 3) a larger training set will provide higher accuracy for genomic selection, and 4) SNPs from previously reported GWAS will have the largest effects. The results from this study could be used to advance predictive breeding for resistance to aphids and cowpea mosaic virus in cowpea.