45 F1 hybrids of ridge gourd in a diallel set involVing 10 inbred parental lines were studied to assess the extent of hybrid vigour in the yield contributing traits, days for first female flowering, days to first harvest, vine length, fruit length, fruit girth, average fruit weight, fruits/plant and total yield/plant. The mean of hybrids was higher than those of parents for all the characters except the fruit maturing. The increase yield in heterotic hybrid was ranged from 23. 7 to 85.8 per cent. In all the characters, the best performing hybrid was significantly better than top parent. In order of merit P2 x P4, P2 x P6 and P3 x PR were best F1 hybrid for total yield and many component characters as they showed 85.8, 80.7 and 65.1 per cent higher yield respectively than the top parent (IIHR-6 an early maturing high yielding variety). The best parental combination of P2 x P4 (IIHR-6 and Coimbatore Long), which exhibited 85.8 per cent high yield over IIHR-6, can be utilised for exploitation of hybrid vigour in ridge gourd.
