黃花蝴蝶蘭育種障礙之表現

Breeding Barriers in Yellow Phalaenopsis Orchids

本研究以具有育種障礙之黃花蝴蝶蘭Phalaenopsis Sunrise Goldamour 'KHM637'和Phalaenopsis Taipei Gold 'STM'為材料，探討蝴蝶蘭雜交育種之障礙致因。以根尖壓製法檢測染色體數目的結果，'STM'之染色體倍體數為三倍體（2n=3x=57），而'KHM637'之染色體倍體數為四倍體（2n=4x=76）。'KHM637'及'STM'進行自交或作為雜交育種母本時，柱頭腔皆無法閉合且無花粉管伸長現象，並在授粉4.3-9.0日後萎凋。由授粉後之柱頭腔開張情形，可初步辨別不親和性的發生。再進一步由柱頭腔的封口、機械傷害及植物生長素處理等試驗處理結果得知，本研究參試品種之雜交育種障礙表現，可初步歸因於三倍體Phalaenopsis Taipei Gold 'STM'的倍體數，及其與四倍體Phalaenopsis Sunrise Goldamour 'KHM637'二者皆有的柱頭腔障礙。 Breeding barriers of producing hybrids by intergeneric, intra-and inter-specific hybridization in phalaenopsis have been found. Phalaenopsis Sunrise Goldamour 'KHM637' was found to be tetraploid and Phalaenopsis Taipei Gold 'STM' a triploid by using the root tip squash method. Neither closure of the stigma cavities nor elongation of pollen tubes occured when 'KHM637' or 'STM' was self-crossed, or was used as the pistillate parent during intraspecfic crossing. Sealing the stigma cavity with a wax film or applying mechanical injurydid not correct the problem, but auxins treatment was helpful. We suggest that the major breeding barrier for Taipei Gold 'STM' is the triploid ploidy and both 'STM' and 'KHM637' have another barrier, i.e. difficulty in stigma cavity closure.