Maternal effects in the progeny generation in zucchini, Cucurbita pepo (Cucurbitaceae)

In plants, environmental effects causing variation in seed mass typically represent the strongest kind of maternal-environmental effect. The influence of fruit removal on subsequent progeny life-history traits was evaluated in zucchini, in terms of the amount of time available for seed development and the timing of fruit production. Early-produced and late-produced fruits remained on treated plants for only 12 d, whereas on untreated controls, both "early" and "late" fruits remained on maternal plants until full ripening (35-40 d and 20-25 d, respectively). Progeny arising from the four kinds of fruit were compared. Seeds from each type of fruit were weighed individually and categorized into three size classes, then germinated and raised to maturity, including a regular harvesting of all fruits 3-d postpollination. Seed-size effects were evident for both vegetative and reproductive traits and carried over to later stages, whereas maternal effects disappeared by day 30 for leaf variables and day 60 for male-flower production. Results are interpreted in terms of postulated levels of growth-promoting hormones.