Summer squash plants are monoecious, producing staminate and pistillate flowers. The flowers are borne at the stem nodes, more precisely at the leaf axils, the junctions of the stem with the bases of the leaf petioles. Staminate flowers differentiate at the first leaf axils. Pistillate flowers differentiate subsequently but develop faster. Consequently, the first staminate and pistillate flowers often attain anthesis simultaneously. After pollination, the pistillate flowers develop into fruits that, under most conditions, are harvested at 2 to 5 d past anthesis (Paris and Maynard, 2008).
The cultivar-groups of summer squash known as Cocozelle, Vegetable Marrow, and Zucchini are single-flowering, that is, one flower bud is produced per leaf axil. On the other hand, the other cultivar-groups of summer squash known as Crookneck, Scallop, and Straightneck, are multiple-flowering, that is, they can produce two, three, or even four flower buds at leaf axils. Worldwide, the former cultivar-groups are more widely distributed and exceed the latter in economic value (Paris, 1996).
In 1996, the senior author initiated a breeding program with the goal of developing cocozelle and zucchini germplasm able to produce more than one flower per leaf axil. Subsequently, an investigation was undertaken to determine the mode of inheritance of the multiple-flowering trait. The objective of this report is to describe this investigation and its result.
Paris, H.S. & Maynard, D.N. 2008 Cucurbita spp. squash, pumpkin, gourds 292 299 Janick J. & Paull R.E. The encyclopedia of fruits & nuts CABI, Wallingford Oxfordshire, UK