| Summary: | 碩士 === 國立高雄大學 === 生物科技研究所 === 98 === In nowadays, Phalaenopsis cultivars undergo cross over continuously for dozens of years, the genomic constitution is fairly complex. General breeders always make cross using parents with good characteristics in the parental genome information unknown circumstances. It usually can’t produce healthy capsules, or seeds in a large number after pollination. Therefore, this study uses the popular cultivars to analyze their genomic constitution of wild species and nuclear DNA content. In addition, some cultivars with their first offspring (F1) were analyzed on their horticultural traits and nuclear DNA content, hoping to get their genetic relation. After obtaining the above information, we can know some of the cultivars due to chromosomal abnormalities, resulted in the difficulty of normal gametes development. An autopolyploidy was made for using tissue culture technology with endomitosis phenomenon for doubling chromosome in Phalaenopsis. In chromosome doubling experiments, a triploid cultivar which have large and small chromosomes called Doritaenopsis Queen Beer was used as experimental material. Two experimented methods were tested as follow: 1. autoallohexaploid induced by horizontal sectioning of protocorm like bodies (PLBs); 2. autoallohexaploid induced by sectioning leaf and roots. In addition, An autoallohexaploid cultivar “P. Wedding Promenade” which induced by our laboratory was also investigated to observe the growth traits.
Based on the different color and size of Phalaenopsis cultivars, nine different groups were assigned for analyzing the genomic constitution of the wild species and their nuclear DNA content. Different groups always contain different species constitutions. In the same group, cultivars usually contain similar species constitution and the similar percentage of species contribution. In the analysis of genomic constitution, large flower groups mostly tetraploid, medium-sized flower, yellow flower and harlequin flower groups have more unstable ploidy, more frequently triploid or aneuploid. In 10 different cross combinations, undergoing analysis of the genomic constitution it was found that parents with tetraploid or diploid were usually able to produce healthy capsules. If the one of parents is triploid or aneuploid, capsules usually had less healthy, only a small number of seeds. In autoallohexaploid induced experiment, it showed leaf and roots from Dtps. Queen Beer compared to other cultivars are more difficult to induce PLBs. Polyploidy induced by horizontal section of PLBs create autoallohexaploidy successfully, and the increase of the number of horizontal sectioning, the proportion of autoallohexaploidy will also increase. In observing the growth traits experiment, hexoploid plants are more instability in growth rate, significant differences in plant size. The same growth stage of the clones, the triploid plants grow in 3.5 inch pot, while hexoploid plants grow in 3.5 inch, 2.5 inch and 1.5 inch, respectively. The results of this survey is similar to previous studies in other plants, polyploid plants always have slower growth rate.
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