Effects of red and blue light ratio on the morphological traits and flower sex expression in Cucurbita moschata Duch.

Squash (Cucurbita moschata Duch.) is an important fruit vegetable that can be long-term transport and storage. Light-emitting diodes (LEDs) are commercially used light sources applied to improve the producing of leaf vegetables in plant factory. However, the influences of LEDs on the plant growth and flower development of fruit vegetables remain unknown. In this study, five effective light quality treatments, including white light, a 10:8 ratio of blue (B) to red (R) light, a 10:4 mixture of blue/red light, red light, and blue light, were used for growing squash and inducing female flowers to maximize production. Our results show that varying light quality influence morphological traits and flower appearance. Both blue and red light improved the development of first and second internodes and induced larger leaves and petiole lengths, whereas 10:4 mixture caused shorter plant heights and decreased internode and petiole lengths. Although 10:8 mixture treatment reduced chlorophyll content, this spectral regime increased leaf number and influenced flower sex development, inducing more female flowers and more fruits. Light quality manipulation thus beneficially influences the growth and flower sex proportion in squash plants. Squash plants under 10:8 mixture treatment exhibited increase in yield, and can be used as a supplementary light treatment in plant factory.