Genetic variability studies in f4 generation of pumpkin (Cucurbita moschata Duch ex. Poir)

Abstract

The field experiment was under taken at Department of Horticulture, Agricultural College and Research Institute, Madurai during Aug-Dec, 2018. The experimental plot was laid out in Randomized Block Design with two replications with eight progenies forwarded from the F3 generation such as, P2 × P5 -1, P2 × P5 -2, P3 × P5 -1, P3 × P5 -2, P5 × P6 -1, P5 × P6 -2, P6 × P5 -1 and P6 × P5 -2, was raised as F4 population. Mean performance, genetic parameters such as GCV, PCV, heritability (h2) and genetic advance as per cent mean (GA) for the traits viz., days to first male flower, days to first female flower, sex ratio, days to first harvest, number of fruits per vine, Average fruit weight, fruit length, fruit diameter, flesh thickness, vine length, number of seeds per fruit, hundred seed weight, total soluble solids, yield per vine was studied. Among the four crosses P3 x P5 (1&2) recorded bigger sized (3.24kg and 3.66kg) less number of fruits per vine (1.69 and 1.75). The P6 x P5 (1 & 2) cross plants in F4 generation recorded small sized (1.28kg and 1.18kg) more number of fruits per vine (2.44 ad 2.56). The higher yield per vine was recorded in big fruited cross P3 x P5 (6.6kg and 7.34kg) whereas the small fruited cross P6 x P5 recorded 6.28kg in family one. Among these traits, days to first male flowering, days to first female flowering and days to first harvest showed low variability coupled with high heritability and low genetic advance over mean which may be attributed to non-additive gene action and response of selection would be limited. Moderate variability consolidated with high h2 and high genetic advance was noticed for sex ratio, number of fruits per vine, number of seeds per fruit, hundred seed weight and TSS in all the progenies indicating the prevalence of additive gene effect. Hence direct selection would be effective for improvement of these traits in further generations.