Gene effects for begomovirus resistance and plant architecture attributes in pumpkin (Cucurbita moschata Duchesne)

Abstract

Knowledge of gene actions governing begomovirus resistance and plant architectural traits is a prerequisite for a successful hybrid breeding programme. Therefore, the gene actions associated with these traits were studied in two intervarietal crosses of Cucurbita moschata (C1: Punjab Nawab × MVSR-6711 and C2: Punjab Nawab × P-135). We used the generation mean analysis of six generations for this purpose. Significant differences between the generation means were observed for all the traits in both crosses. The parental lines differed significantly in most of the studied traits. The nature and magnitude of the gene effects of seventeen traits varied by trait and cross. A simple additive dominance model was adequate for the internode number, leaf length and width, petiole length, fruit weight and cavity diameter in C1 and the number of fruits/plant in C2. The non-allelic interaction was found to be significant for a majority of the traits including the per cent disease index of the squash leaf curl China virus, tomato leaf curl New Delhi virus and their mixed infections, which indicated, that recurrent selection in biparental progeny might be useful for the accumulation of genes with additive effects. Duplicate epistasis was observed for the vine, internodal and peduncle length in C1 and the internode number, petiole and peduncle length, peduncle and fruit polar diameter in C2. This information will help to establish a breeding program for the simultaneous improvement of virus resistance and yield traits in pumpkins.