Abstract: The genetic effects of yield traits, plant traits and maturity traits of summer squash were analyzed by using three inbred lines with significant difference. The results indicated that F1 had different heterosis on the main yield traits. Fruit number per plant, ratio of fruit setting and node of 1st female flower accorded with the pattern of additivedominance, while node of 1st female flower had negative dominance effect primarily. Plant height, leaf number, internode length, individual fruit mass and early flowering season were coincident with the pattern of additivedominanceepistasis. But the genetic effects of those traits had difference: Plant height had mostly additive effect; Early flowering season was mostly additive effect and additive dominance effect; Leaf number was mostly additive effect and dominance effect; The broad heritability of individual fruit mass was relatively low.

Key words: Summer squash, Agronomic trait, Heterosis, Genetic effect