台灣芭蕉[Musa formosana (Warb.) Hayata]種原之蒐集、評估與遺傳歧異度分析

Abstract

本論文以台灣原生野生香蕉作物-台灣芭蕉為材料，經由系統地探查與種原材料蒐集，以進行特性調查和遺傳歧異度分析，做為種原保存、保護、管理與利用的參考。試驗結果指出，原生台灣芭蕉廣泛分布於台灣本島海拔1400公尺以下，日照充足的河流沿岸山谷或集水區及平緩的山坡地。植株的主要特性包括: 吸芽由匍匐莖發育而成，新抽出葉之葉背與中肋均有紫紅色條紋，基部花序為兩性花。依據雄花苞苞片與成熟果實果皮有無紫紅色條紋，可將台灣芭蕉族群分為有紫紅色條紋者(PR group)及無紫紅色條紋者(YG group)二大群，前者判定為台灣芭蕉，後者則尚待探討。 利用16組 Musa acuminata專一的SSR引子對分析台灣芭蕉族群的遺傳歧異度，結果指出台灣芭蕉族群已有遺傳分化的趨勢。因此若要進行原地保存(in situ conservation)，可選擇新竹與宜蘭交接之山區及阿里山公路石槕以上的區域進行保存，另外林試所太麻里研究中心內之山區亦是一處很好的保存園。若進行異地保存(ex situ conservation)，則應在新竹與宜蘭交接之山區及阿里山公路石槕以上的區域採集較多的樣本，此外在嘉義龍巖至石槕間、屏東與台東花蓮間及貢寮之獨立族群也必需加以保存。 由形態性狀、intra-SSR、ITS區序列與基因組大小的資料顯示，台灣芭蕉與M. acuminata及M. balbisiana (目前世界上主要栽培品種的原種)為不同的三群，推論應是地理隔離所形成。由於華蕉系的基因組為M. acuminata complex，因此未來應用台灣芭蕉於香蕉作物的品種改良應朝品質以外的特性著手，例如耐寒性或香蕉黃葉病的抗病性等。 應用105 spore/ml的接種液進行人工剪根接種評估台灣芭蕉對香蕉黃葉病病原菌的反應，結果顯示台灣芭蕉的發病率或組織分離率均較栽培種'北蕉'者低。未來需進一步確認台灣芭蕉抗病特性，才能擬定有效率之利用策略。 本論文設計之台灣芭蕉專一遺傳標誌，能快速與精確區別其他基因組的材料，將來不僅可用於鑑定種原，更是保護本土遺傳資源的重要工具。

The objective of this thesis is to dissected the genetic diversity of Musa formosana native in Taiwan through systemic exploration, collection and characterization in order to assist decisions making for conservation, protection and utilization. The result shown that M. formosana distribute around the mountain areas below 1400 m in the main Taiwan islands. It has stoloniferous sucker, red-purple streak in the lower epidermis blades and the vein at 7-10th leaf; basal nodes bear hermaphroditic flowers. According to the color in the bracts of male bud and fruit skin, we could separate it into two groups. Plants with red-purple streak on the bract of male bud and fruit skin belonged to PR group and declared as M. formosana based on Flora of Taiwan. Plants with no red-purple streak were marked as YG group. The relationship between them needs intensive study. Result of analysis of genetic diversity using 16 M. acuminata-specific SSR primer pairs revealed the population of M. formosana was divergent and 87.08% of total variation was within the collection site. In term of in situ conservation, we proposed the Wufong-Chilian population, Alisan National Park population, and Tamali population were the best choice. In term of ex situ conservation, it is necessary to sample more individuals in main divergent areas, such as Hsinchu-Yilian and Chiayi-Kaohsiung areas, and other individuals in isolated population if we plan to construct a repository to preserve their diversity for the future. The genome of M. formosana was quite different from A genome and B genome as revealed by the information in genome size, SSR polymorphic data, and sequence difference of ITS region. The Cavendish group is M. acuminata complex. Therefore, the utilization of- M. formosan should not focus on quality characters. We suggest the characters related to biotic or environmental tolerance will be better choice. Using root-pruning inoculated method, the response to the105 spore/ml solution of TN5 isolate of Foc race 4 indicated the disease severity and isolate ratio of M. formosana were lower than that of cv. 'Pei Chiao'. It is suggested that more information about the characteristic of resistance to Foc race 4 should be developed before apply to breeding program. Genome identification is very important in Musa classification, breeding, and germplasm management. In this study, we identified the genome size and developed one specific primer pair to discriminate M. formosana to other Musa genome. It will be helpful for the protection, utilization, and management of M. formosana.