本研究以13條ISSR引子所產生之175個多型性條帶來評估台灣102個短柱山茶(Camellia brevistyla)收集系之遺傳歧異度,結果顯示收集系間之遺傳相似性介於34.1% ~ 95.1%之間,平均遺傳相似性為73.1%。群聚分析結果也顯示此102個收集系以及3個外群對照(Camellia kissi)共分成8大群,且其所對應之地理區域將這些族群大致區分為南北2區。此外,分子變方分析結果顯示族群內的變異(75%)大於族群間的變異(18%),而所有收集系之分化係數(Gst)為0.534,顯著高於一般異交風媒花植物(Gst=0.143)和蟲媒花植物(Gst=0.197)之平均值,且基因流轉值(Nm= 0.436)小於1,顯示台灣整體短柱山茶族群間之基因交流受到阻礙;北部地區具有較大之遺傳歧異度(H=0.317)、物種豐富指數(I=0.477)及族群分化係數(Gst=0.495),可視為台灣短柱山茶之遺傳變異中心,而這些結果將可提供未來進行短柱山茶種原收集及利用之參考。最後,從短柱山茶含油量有關之cDNA primer的PCR定序結果發現,這些專一性條帶之DNA序列具高度相似性,這意味著這些引子的序列為控油基因之保守序列。
This study has been undertaken to assess the extent of genetic diversity from the collected accessions of 102 Taiwanese Camellia brevistyla, 13 selected Inter-simple sequence repeat (ISSR) primers were used and totally 175 polymorphic bands were generated. The results show that average of genetic similarity of these collected accessions was 73.1%, ranging from 34.1% to 95.1%. According to cluster analysis, these collected accessions and three outgroups (Camellia kissi) as controls were divided into eight large groups, and all populations were roughly divided into two geographic regions for northern and southern parts. In addition, the results from analysis of molecular variance (AMOVA) appeare that the variation within populations (75%) was greater than the variation between populations (18%). The differentiation coefficient (Gst) of all collected accessions was 0.534 which was significantly higher than the average of Gst from outcrossing wind-pollinated plants (0.143) and entomophilous-pollinated plants (0.197). The value of gene flow (Nm=0.436) was lower than 1, indicating that the gene flow of all populations of C. brevistyla in Taiwan was hampered. The values of heterozygosity (H = 0.317), Shannon's information index (I = 0.477), and genetic differentiation coefficient (Gst =0.495) of C. brevistyla in northern region were greater than those of in southern region, demonstrating that the center of genetic variation of Taiwanese C. brevistyla was in northern part of Taiwan. This study provides valuable information for germplasm collection and genetic improvement. Finally, all DNA sequences of those PCR products of specific band generated from oil-related cDNA primers were highly similar in C. brevistyla. This implies that DNA sequences from these oil-specific primers are highly conserved in C. brevistyla.