Author：Fure-Chyi Chen*, Shih-Wen Chin

Department of Plant Industry, National Pingtung University of Science & Technology, Taiwan
* Author for correspondence: furechen@mail.npust.edu.tw

Abstrct：

    Phalaenopsis is one of the most popular and important orchids produced at commercial scale. New cultivars are produced by selection of seedling plants during their flowering stage. After selection of orchid plants with desirable traits, tissue culture and mass production of young plantlets were achieved through flower stalk node culture in vitro. Cross hybridization by artificial pollination among different parental hybrids usually can lead to capsule set and seed formation. However, breeding barriers are present in Phalaenopsis and its alliance genera with the mechanisms largely remained unknown. Meiotic chromosome behavior of the pollen mother cells (PMC) was investigated to examine whether it is correlated with seed set in different breeding parents of both Doritaenopsis and Phalaenopsis orchids. The results showed that high percentage of normal tetrad, in addition to regular bivalent chromosome paring, generally suggests high fertility. Unreduced gametes such as dyads were observed during the PMC meiotic process and the number of the dyads could be increased by treating young flower buds with mitotic inhibitors such as colchicines and trifluralin. Through cross pollination of chemically conditioned pollinia, chance of obtaining polyploidy seedlings is expected to be increased. Through these meiotic analysis and chemical treatment, breeding efficiency of phalaenopsis orchids will be increased.

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