Quantitative trait loci analysis of brown blotch resistance in cowpea variety KN1

Abstract

Cowpea is one of the most important crops in West Africa and is essential for the region’s food and nutrition security and economic development. Consequently, improving its agronomic performance and yield is a desirable goal. Brown blotch disease, caused by the fungal pathogen Colletotrichum capsici, is an important constraint of cowpea productivity, and at present, only limited genetic resources are available for breeding improved brown blotch-resistant varieties. The current study has characterized the genetic basis for brown blotch resistance conferred by the cowpea cultivar KN1 and identified a major dominant quantitative trait locus (QTL) for resistance on chromosome Vu02. A segregating F2 population (n = 200), derived from a cross between KN1 and brown blotch-susceptible Tiligre (KVx775-33-2G), was developed and scored for disease severity following controlled inoculation. A subset of the population (n = 94) was genotyped with 99 newly developed allele-specific polymerase chain reaction (AS-PCR) markers, and multiple interval mapping was performed. One major and three minor QTL were identified. This is the first reported mapping of QTL conferring resistance to C. capsici in cowpea, and it is expected that the markers identified here will be a valuable resource for developing elite cowpea cultivars with resistance to brown blotch.Electronic supplementary materialThe online version of this article (10.1007/s11032-018-0867-1) contains supplementary material, which is available to authorized users.

Cowpea Constraints and Breeding in Europe

“…A new variety, VBN 09-013 (VBN 3), was created with parallel resistance to rust, anthracnose and Bean mosaic virus [ 289 ]. The genomic regions harboring disease resistance genes are currently beginning to be mapped [ 290 , 291 , 292 ]. Cultivation of resistant varieties is considered the most effective and environmentally friendly method for confronting viruses diseases.…”

Confirmation de QTL et validation de marqueurs SNPs associés à la résistance du niébé à Colletotrichum capsici, agent responsable de la maladie des taches brunes

“…Plusieurs QTL de Colletotrichum lindemuthianum ont été signalés sur le chromosome 2 de Phaseolus vulgaris, un parent proche du niébé, ce qui suggère que ce groupe de liaison pourrait jouer un rôle important dans la résistance aux espèces de Colletotrichum (Campa et al, 2014;Oblessuc et al, 2014;Silva, 2017). Récemment, Ohlson et al (2018) (Ferreira et al, 2006). Les effets additifs élevés observés au 21 ème JAI (1,0136) et au 28 ème JAI (1,0132) indiquent une contribution significative de l'allèle parental mâle (KN-1) à la résistance.…”

“…Collard et al (2006) ont, quant à eux, confirmé et validé respectivement des QTLs et marqueurs SSRs liés à la résistance à Fusarium pseudograminearum, responsable de la maladie de la pourriture de la couronne du blé. Ohlson et al (2018) ont aussi cartographié 4 QTLs dont le qBBDR1 est associé à la résistance à C. capsici chez le niébé.…”