Abstract
Key messageA QTL for aphid resistance on pepper chromosome 2 was identified and validated. This QTL affects aphid survival and reproduction, and was fine mapped to a locus containing LRR-RLK analogues.Myzus persicae is one of the most threatening insect pests that adversely affects pepper (Capsicum) cultivation. Resistance to aphids was previously identified in Capsicum baccatum. This study aimed at elucidating the genetics of aphid resistance in C. baccatum. A QTL analysis was carried out for M. persicae resistance in an F2 population derived from an intraspecific cross between a highly resistant plant and a susceptible plant. Survival and reproduction were used as resistance parameters. Interval mapping detected two QTLs affecting aphid survival (Rmpas-1) and reproduction (Rmprp-1), respectively, both localized in the same area and sharing the same top marker on chromosome 2. Use of this marker as co-factor in multiple-QTL mapping analysis revealed a second, minor QTL (Rmprp-2) only affecting aphid reproduction, on chromosome 4. Fine mapping confirmed the effects of Rmpas-1 and Rmprp-1 and narrowed the major QTL Rmprp-1 down to a genomic region of 96 kb which is predicted to encode four analogues of resistance genes of the receptor-like kinase family containing a leucine-rich repeat domain (LRR-RLKs). This work provides not only initial information for breeding aphid-resistant pepper varieties, but also forms the basis for future molecular analysis of gene(s) involved in aphid resistance.
Highlights
Pepper (Capsicum spp.) is one of the economically most important and widely cultivated vegetable crops
Among the different aphid species feeding on pepper, the green peach aphid (GPA), Myzus persicae, is one of the most threatening (Fereres et al 1993)
The F 2 population showed a large variation for GPA performance based on the two parameter used: 20–100% survival of the aphids placed on the plant and 0.2–13.3 new nymphs produced per aphid (Fig. 1)
Summary
Pepper (Capsicum spp.) is one of the economically most important and widely cultivated vegetable crops. Its cultivation is constrained by aphids (Frantz et al 2004; Herman et al 2008). Aphids can damage pepper plants in many ways, leading to chlorosis, defoliation, wilting and flower abortion. The most important damage to pepper plants is done indirectly by the viruses that are vectored by the aphids (Black et al 1991; Kennedy et al 1962; Kenyon et al 2014). Given the fact that more and more aphid species have developed resistance against the pesticides (Bass et al 2014; Devonshire et al 1998; Foster et al 2000) and that insecticides negatively affect the environment, varieties resistant to the GPA may be a more
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