影響榴槤(Durio zibethinus Murr.)結實之因子I、開花與授粉

Abstract

There are seven species that yield edible fruit in genus Durio: D. zibethinus Murr., D. kutejensis (Hass.) Becc., D. oxleyanus Grif., D. graveolens Becc., D. testudinarium Becc., D. dulcis Becc. and D. grandiflous (Mast.) Kost. & Soeg., with D. zibethinus as the major cultivar(local name is durian). Durians are native of South-East Asia with Borneo and Sumatra as the centers of diversity. Thailand, Indonesia and Malaysia are the major production country. The main production season, starting from March till December, is believed to be affected by the dry-wet season in production areas. In general, the floral initiation is achieved when the draught stress lasted for 15-20 days. A whole floral development needs about 60 days that can be divided in to seven stages. Flowering habits are different among individual species. Generally, Durian flower starts to bloom at 16:00, pollen sheds from 19:00, and floral parts begin to abscise around 23:00. All of the floral parts except the gynoecium will have abscised by 10:00 on the following day. Stigma is receptive within 24 hrs before and after full bloom, but receptivity achieves the maximum within 12 hrs after full bloom. The viability of pollen after shedding can maintain high viability (＞70%) of germination when stored in room temperature within 24 hrs. The main pollinator of Durian appears to be bats. Fruit set rate is different among cultivars, however, the fruit set of selfing is poor (＜10%) for some cultivars, and improves greatly with cross-pollination. Some cultivars, for example, 'D99', 'D24', 'Gumpun' and 'Luang' have been shown to be of low productivity. Beside this, 'Monthong' and 'Chanee' also exhibit low productivity when selfing. The metaxenia effects of Durian pollen influenced the harvest time of fruit, fruit set and fruit quality. So the pollination tree should be arranged in the orchard with a careful selection of pollination tree cultivar. Alternatively, hand pollination and bats conservation can improve fruit set.