Effects of perimeter trap crop pollen on reproduction in butternut squash (Cucurbita moschata)

Abstract

Perimeter trap cropping (PTC) uses an attractive crop to concentrate pests at borders and reduce pesticide use while maintaining yield. A possible disadvantage of PTC could be pollen flow between border and main crops that are not interfertile. The effects of pollen composition and amount on seed and fruit production were investigated between a main crop species, butternut squash (Cucurbita moschata Duch. ex Poir), and a PTC species, blue hubbard (C. maxima Duch.). Butternut squash plants were hand pollinated in the greenhouse with three pollen composition treatments crossed with four pollen amounts. Pure butternut squash pollen and mixed pollen produced more seeds per fruit and heavier seeds than pure blue hubbard pollen, revealing some incompatibility between butternut and blue hubbard. Saturating pollen amounts produced up to six times more seeds than lower pollen amounts. Pollen composition did not influence fruit set or fruit weight, which are of central importance for crop yield. This study suggests that pollen flow between blue hubbard borders and butternut squash should not interfere with crop production as long as sufficient conspecific pollen is deposited on stigmas.