Pumpkin is an important plant, which is one of the oldest domesticated crops of the Neolithic revolution. In this study, seed yield production and its different components fruit length, fruit diameter, fruit length/fruit diameter ratio (FL/FD), diameter of flesh, diameter of seed core, fruit weight, weight of 1000 seed from 24 lines of pumpkin grown in Iran were examined. Twenty five characters in all plant lines were measured by a Descriptor (UPOV) and data were subjected to cluster analysis. Results showed that plant lines were divided in four groups. In all groups, regression comparisons were made for modeling the effect of different characters on seed yield, results also showed that fruit weight and fruit length in all groups had the most direct effect on seed yield. In conclusion, these traits are suggested as the best indirect selection criteria to improve the seed yield genetically in Cucurbita spp. genotypes especially in preliminary generation of breeding and selection programs.
Key words: Pumpkin (Cucurbita pepo), path analysis, fruit weight, fruit length.