Genetic variability in NTU selections of Rhododendron accessions

早年由台灣大學園藝系馬溯軒教授所雜交育成之杜鵑雜交系，因親本不明確，故期望利用植株外觀型態調查，並配合RAPD分子遺傳標誌，瞭解其遺傳變異性。另擬由分子層次探討雜交系杜鵑之生物歧異度，種間分子標誌與其表現型態特徵，期盼能藉此達到提昇種原蒐集及保存之效率，並可為繁殖時參考的依據。 調查的葉部型態特徵包括葉片長度、葉片寬度、葉柄長度、葉尖角度、葉基角度及葉片長寬比。經主成份分析，前三主成份軸共可解釋80.83%的變異量。透過主成份分析結果可得知，葉尖角度與葉基角度為主要代表性狀。調查的花器型態特徵包括花朵直徑、主瓣長度、主瓣寬度、雌蕊長度、雄蕊長度、雄蕊數目以及花朵顏色。經主成份分析，前四主成份軸共可解釋86.26%的變異量。透過主成份分析結果可得知，雄蕊數目、雄蕊長度與花朵直徑為主要代表性狀。 RAPD分析方面，進行PCR反應的25個引子表現多型性，共產生109個條帶。以109個條帶進行群集分析，與外觀型態調查之分群結果有部份相似。Since the parent of the hybrid of rhododendron, which were conducted in early days about 1970 by Professor Ma, department of horticulture, NTU, is not clearly recognized, we are trying to understand the genetic variability of these Rhododendron accessions , in addition the RAPD analysis constructing the molecular inheritance marks. Besides, the molecular-level approach of discrepancy of hybrid rhododendron and the molecular marks between breeds will be held for trying to raise the efficiency of acquisition and conservation of parent plants and be the accordance of reproduction. The leaf characters investigated included leaf length, leaf width, leaf stalk length, leaf tip angle, leaf base angle and leaf length/ leaf width ratio. According to the ordination pattern of the first three principal components, it explained 80.83% of the observed variation. Our result indicated that the leaf tip angle and leaf base angle are the 2 major discriminating traits could be useful for Rhododendron genetic variance analysis. The flower characters investigated included flower length, main petal length, main petal width, pistil length, stamen length, stamen number and flower color. According to the ordination pattern of the first four principal components, it explained 86.26% of the observed variation. Our result indicated that the stamen number, stamen length and flower length are the 3 major discriminating traits could be useful for Rhododendron genetic variance analysis. 25 10-mer random primers were screened in the RAPD analysis, which produced polymorphism. The 25 primers generated total 109 reproducible monomorphic bands. According to the dendrogram of 29 Rhododendron accessions revealed by UPGMA cluster analysis on the basis of 109 polymorphic bands, our result is similar with the leaf and flower characters