Identification of quantitative trait loci associated with resistance to cucumber mosaic virus in Capsicum annuum

QTL analysis for resistance to cucumber mosaic virus (CMV) was performed in an intraspecific Capsicum annuum population. A total of 180 F3 families we re derived from a cross between the susceptible bell-type cultivar Maor and the resistant small-fruited Indian line Perennial and inoculated with CMV in three experiments carried out in the USA and Israel using two virus isol ates. Mostly RFLP and AFLP markers were used to construct the genetic map, and interval analysis was used for QTL detection. Four QTL were significant ly associated with resistance to CMV. Two digenic interactions involving ma rkers with and without an individual effect on CMV resistance were also det ected. The QTL controlling the largest percentage (16-33%) of the observed phenotypic variation (cmv11.1) was detected in all three experiments and wa s also involved in one of the digenic interactions. This QTL is linked to t he L locus that confers resistance to tobacco mosaic virus (TMV), confirmin g earlier anecdotal observations of an association between resistance to CM V and susceptibility to TMV in Perennial. An advanced backcross breeding li ne from an unrelated population, 3990, selected for resistance to CMV was a nalyzed for markers covering the genome, allowing the identification of gen omic regions introgressed from Perennial. Four of these introgressions incl uded regions associated with QTL for CMV resistance. Markers in two genomic regions that were identified as linked to QTL for CMV resistance were also linked to QTL for fruit weight, confirming additional breeding observation s of an association between resistance to CMV originating from Perennial an d small fruit weight.