QTL analysis reveals new eggplant loci involved in resistance to fungal wilts

Abstract

Fusarium spp. and Verticillium spp. are widespread soil pathogens responsible for vascular wilts causing heavy yield losses in eggplant (Solanum melongena) as well as in many other crops. Here we report on the identification of QTLs affecting the resistance to Fusarium and Verticillium in an F2 intraspecific population of 156 individuals bred from the cross ‘305E40’ × ‘67/3’, we previously characterized for key agronomic and biochemical traits. The female parent (‘305E40’) is an androgenetic introgressed line carrying the resistance locus Rfo-Sa1 derived from Solanum aethiopicum. The line is fully resistant to Fusarium and also displays a previously uncharacterized partial resistance to Verticillium. The male parent (‘67/3’) is an F8 selection from the eggplant intra-specific cross cv. ‘Purpura’ x cv. ‘CIN2’ which, unexpectedly, revealed a not previously characterized partial resistance to Fusarium, but it is highly susceptible to Verticillium. The degree of resistance of the F2 population was assessed following artificial inoculation in greenhouse (Fusarium) or growth chamber (Verticillium) of F2:3 progenies obtained by selfing each F2 individual. Other than a major QTL for the resistance to Fusarium, which lies in the genomic region of the Rfo-Sa1 locus, major and minor QTL influencing the response to both Fusarium and Verticillium were spotted, and putative tomato orthologous genes were identified as well. The markers linked to the spotted QTL may find application in the context of marker-assisted breeding.