Estimation of combining ability of hull-less-pumpkin (Cucurbita pepo L. var. styriaca ) lines for yield component

Estimates of combining ability help determine the value of hull-less pumpkin (Cucurbita pepo L. var. styriaca) lines in producing new hybrids with high yield and better quality. This research was conducted to estimate the general and specific combining abilities and heterosis in six inbred lines proposed for hull-less pumpkins at the University of Guilan. Analysis of variance indicated that responses for all traits differed significantly. The highest fruit yield and seed length were related to the hybrid 14×16, the highest number of seeds was related to the hybrid 16×23, the highest percentage of oil was related to the hybrid 11×14 and the highest yield of oil was related to 11×23. Considering the high value of combining ability and the heterosis compared to the average of the parent and high parent, it is possible to increase the oil yield and the seed yield by using the 11×23 hybrid. The 16×23 hybrid proposes to increase the number of seeds. The best specific combining ability (SCA) for seed number was associated with the 16×23. The 11 × 14 had the best SCA for the oil yield per hectare. The 11× 23 had the best SCA for the seed yield per hectare. Significant specific combining ability and high heterosis for traits indicated low additive and high dominant gene action on hull-less pumpkin traits, therefore crossing between lines to release new hybrid cultivars is necessary for Iran's pumpkin breeding program.