Evaluation of cultivated luffa for fruit setting traits under natural Long-Day conditions

Luffa is one of the major vegetable and fiber crops widely cultivated throughout Asia. The sexual expression of cultivated luffa is modified by photoperiod, where long days delay female flowering, resulting in late fruit-setting and yield losses when grown during the summer season in south-east Asia. A total of 183 cultigens, including short and long ridge gourds (Luffa acutangula Roxb.) and sponge gourds (Luffa cylindrica Roem.) were collected from South China and evaluated for two fruit setting traits. Firstly, for first pistillate flower node and secondly for female to male ratio under natural long day summer conditions, high temperature and abundant precipitation in Guangzhou, China. The results showed that luffas exhibited a wide range of variation for these two traits. Short ridge gourds had the highest numbered first pistillate flower node, followed by long ridge gourds and sponge gourds, indicating that ridge gourds were more sensitive to long-days. The ridge gourds also showed a higher female to male ratio than sponge gourd. Twenty-two long-day insensitive cultigens were identified, which could be directly used for summer commercial production in South China. The material ‘Lin4-1’ had the lowest nodal position for first pistillate flower and could be exploited in future breeding programmes.