Marked improvement of fruit set in Thai durian by artificial cross-pollination

Abstract

Artificial self-pollination and cross-pollination were performed in addition to open pollination in four Thai durian cultivars, ‘Mon Thong’, ‘Chanee’, ‘Kradum Thong’ and ‘Phaung Manee’, for investigating the efficiency of pollination to fruit set. In all cultivars, open pollination treatment resulted in the lowest fruit set, ranging from 0 to 1.4% at harvest. This may be due to lack of pollination. Self-pollination treatment also resulted in lower fruit set, especially in ‘Mon Thong’ (7.7%), ‘Chanee’ (3.6%) and ‘Phaung Manee’ (0%), indicating a self-incompatibility in durian. When ‘Kradum Thong’ was used as pollen parent, fruit set percentage was significantly high in ‘Mon Thong’ (27.2%), which is a leading cultivar in Thailand. High fruit set was also achieved in ‘Chanee’ (16.3%) by ‘Kradum Thong’ pollen, although its value was not significantly separated from values of other pollen parents tested. Artificial cross-pollination using ‘Kradum Thong’ as a pollinizer was strongly recommended for commercial durian cultivation. The observation of pollen-tube growth in vivo revealed that pollen germination on stigma and pollen-tube elongation in style were not inhibited by self-pollination. Thus, durian seems to have a late-acting self-incompatibility.