Cucurbit Genetics Cooperative Report 3:48 (article 29) 1980

Fruit Development in Summer Squash in Relation to the Number of Stigmatic Lobes Receiving Pollen

Vincent J. Tepedino

Utah State University, UMC 53, Logan, UT 84322

Although insects are necessary for the pollination of monoecious summer squash, Cucurbita pepo, it is not known if insect visitors must deposit pollen on all three stigmatic lobes of the pistillate flower for normal fruit development to occur. During a study comparing the pollination efficiency of squash bees, Peponapis pruinosa, and honey bees, Apis mellifera, on a small planting of Italian Black Zucchini in North Logan, UT, the opportunity was taken to clarify this point. Prebagged pistillate flowers were hand pollinated by rubbing the anther of a flower from another plant across one or two of the stigmatic lobes. Flowers were immediately rebagged after treatment.

Of 12 flowers receiving pollen on only one stigmatic lobe, ten produced "normal" appearing fruit (mean time to ≥18 cm = 7 days). Four of five flowers pollinated on two stigmatic lobes produced similar fruit (mean = 6.3 days). Although the fruits appeared typical externally, it is possible that a comparison of seed production would have revealed differences.