Multilocus Genome‐Wide Association Identifies QTL and Candidate Genes Associated With Resistance to Flower Bud Thrips ( Megalurothrips sjostedti ) in Cowpea Minicore Population

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ABSTRACT Flower bud thrip ( Megalurothrips sjostedti Trybom) is a major insect pest of cowpea in sub‐Saharan Africa causing flower abortions resulting in significant yield loss. The objective of this study was to identify cowpea genotypes with resistance to flower bud thrips and map genomic regions associated with resistance to flower bud thrips in cowpea. A total of 220 Minicore cowpea genotypes were evaluated for flower bud thrips resistance under natural infestation in five environments and genotyped with a high‐density panel of 51,128 polymorphic SNP markers. Genotypes TVU‐3804, TVU‐7647 and Ecute were resistant to flower bud thrips across environments. Eleven significant GWAS signals associated with resistance to flower bud thrips in cowpea were detected on 8 chromosomes: Vu02 , Vu03 , Vu04 , Vu06 , Vu08 , Vu09 , Vu10 and Vu11 with marker 2_24860 (25.63 Mb) on chromosome Vu02 being consistently significant across environments. Positional candidate genes Vigun02g101600 (0.05 kb) and Vigun02g100900 (60.59 kb) from marker 2_24860 (25.63 Mb) on Vu02 encode leucine rich repeat and NB‐ARC domains‐containing disease resistance protein, respectively. These proteins are members of the disease resistance genes (R‐genes) in the legume family, involved in both plant innate immunity and induced plant‐specific defence responses. The identified genotypes and markers can be validated for use in marker assisted selection for flower bud thrips in cowpea.

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