Genetic basis of the resistance of a passion fruit segregant population to Cowpea aphid-borne mosaic virus (CABMV)

Cowpea aphid-borne mosaic virus (CABMV) infects many species of economic interest, accounting for up to 100 % reduction in productivity in passion fruit. The present work aimed to identify resistant genotypes in passion fruit populations from backcross and study resistance inheritance. The assessments were conducted in 369 genotypes, including the parents P.edulis (susceptible), P.setacea (resistant), the hybrid (P.edulis X P.setacea) and RC1. Evaluations were performed by AUDPC, obtained through a rating scale, and asymptomatic plants were subjected to ELISA test. ANOVA was significant (p<0.05) for AUDPC. The estimation of genetic parameters indicated heritability of 94 %; IV of 0.26 and CVe of 27.9 %. The percentage of resistant genotypes in the progenies was 14.87 and 22.64, according to ELISA, for progenies one and two, respectively. The quantities of resistant and susceptible individuals obtained in backcrosses were significantly different from the amounts of expected resistant and susceptible individuals (X-2 > 3.84; G.L. 1; p>0.05), and thus the hypothesis of monogenic inheritance was rejected. The inheritance for resistance is polygenic, and there is gain with selection provided that large populations and more complex methods are used, such as backcross breeding and recurrent selection.