Reciprocal Effects Suggest Maternal and Extranuclear Influences on Fruit Traits in Winter Squash Breeding

This study on winter squash (Cucurbita moschata) explored genetic variability and the effects of reciprocal crosses on 13 traits related to plant growth and seed oil yield. Using a complete diallel mating design, significant genetic variability was found in 8 traits. General combining ability (GCA) effects were dominant for flowering time, indicating additive gene action, while specific combining ability (SCA) was significant for fruit mass and other traits, indicating non-additive effects. Notably, specific reciprocal effects suggested maternal or extranuclear influences on fruit mass and other traits, highlighting the importance of cross orientation. Parents 301 and 516 were identified as promising for reducing the crop cycle, and certain hybrid combinations, particularly involving parents 117, 301, or 516, showed superior performance. Crosses 117 × 301, 301 × 516, and 516 × 447 are recommended for breeding programs focused on oil yield.