Interspecific hybridization between sponge gourd ( L.) and 'Satputia' ( Singh & Bhandari) for preintrogression of cluster bearing, high yield and gynoecism.

Interspecific hybridization with 'Satputia' (bisexual and cluster bearing) can be highly useful for the introgression of cluster bearing, high yield and gynoecism in sponge gourd (monoecious and solitary bearing). However, the occurrence of self-pollination in closed flowers and anthesis of two species at different time intervals creates hindrance in interspecific hybridization. The present investigation highlighted that the reciprocal interspecific cross (Satputia × sponge gourd) is more successful for development of F hybrid and its further utilization in development of segregating generations. Pre-anthesis emasculation (28 h before anthesis) of Satputia buds in the evening and pollination with sponge gourd (PSG-9) in the morning on the day of anthesis resulted in high fruit set. Interspecific hybrids were monoecious and morphologically intermediate for most of the vegetative, flower and fruit traits. The seed of hybrid vines was vigorous than both the parents with respect to size and weight. Ample pollen production, pollen viability and high fruit set on selfing confirmed the fertility status of vines. Although pollen size was less than both the parents, but the pollen density improved in F vines. Fertile hybrids could be easily used to generate F and BCP and TCH segregating generations. In F generation, gynoecious, adroecious, andromonoecoius, monoecious and cluster bearing vines of variable length and fruit size were observed. In back cross and triple cross generations, most of the vines were monoecious except a few adroecious and gynoecious with improved fruit size, vine growth and bearing capacity. Backcross and triple cross with sponge gourd displayed a shift towards this species.