以園藝性狀與簡單重複性序列評估臺灣芥藍之遺傳歧異度

Genetic Diversity among Chinese Kale in Taiwan Assessed by Horticultural Traits and SSR Markers

蔣順惠(Shun-Hui Chiang)

指導教授 ： 林彥蓉

國立臺灣大學/生物資源暨農學院/農藝學研究所/碩士(2014年)

https://doi.org/10.6342/NTU.2014.02333

摘要

十字花科蕓薹屬甘藍類蔬菜廣為世界各地不同民族栽培利用，而芥藍屬於其下之變種，分類上較接近於原始型的甘藍類植物，葉片不結球且分皺葉或非皺葉，花色有黃色和白花色兩種等植株形態多變，但一般以花色為主要區別特徵。主要栽培於東南亞、臺灣及中國大陸等地。在臺灣以採收小葉菜用之白花芥藍及採收花薹的黃花芥藍為栽培之主流，而品種以開放授粉之農民自留種或地方種為主，部分葉菜用品種採用一代雜交之商業品種，因此有利於遺傳變異之保存。一般認為芥藍與青花菜及花椰菜等等其他主流甘藍類作物相比，具有早生及耐熱之特性，在極端天氣頻繁發生的現在，芥藍可能為甘藍類作物育種之重要資源。由了解其種原間遺傳歧異度及遺傳結構，將有助於制定育種策略，提升育種工作之效率。
本試驗採用25個芥藍蒐集自臺灣各地之種原，並以1個青花菜商業品種作為芥藍與近緣物種歧異度之參考。分別就外觀性狀及分子標誌多型性兩方面探討種原間的歧異度。外觀性狀以七個性狀調查資料對25個芥藍種原進行主成分分析，視覺化種原間以性狀資料建構的分類關係。另外利用20個簡單重覆序列（Simple sequence repeat；SSR ）分子標誌對每個種原內20個個體進行對偶基因片段之擴增。總共使用520株單株擴增之對偶基因以計算種原內之對偶基因頻度進行種原間及種原內遺傳歧異度分析。
試驗結果在外觀性狀調查資料顯示芥藍種原之分類大致可按花色分為兩大類，與過去研究相同。而SSR分子標誌部分之結果顯示，一代雜交種及專業種苗商之商業品種種原間遺傳歧異度明顯低於其他農民自留種種原。而種原間包含青花菜在內，以modified Roger’s distance表示之遺傳距離介於0.31–2.79，而芥藍種原間之遺傳距離介於0.31–2.36。而利用遺傳距離之主座標分析及UPGMA 親緣樹圖則顯示可將種原粗略分為黃花及白花兩群，但其中仍少部分種原未按照花色分群。結合UPGMA親緣樹圖及族群分化指數之結果顯示，整體芥藍種原間大部分呈現高度遺傳分化，且黃花芥藍種原間遺傳距離較白花芥藍種原間大，可能由於授粉及採種方式不同所致。此外，而黃花芥藍種原內具有兩個次群集，白花種原內有1個，都是次群集內種原相似度極高可能群內種原最初來源相同。在明確了解芥藍種原內及種原間之遺傳歧異度，能更妥善運用資源進行重要種原維護及提供更多種原間資訊給育種者以提升育種工作之效率。

關鍵字

芥藍 ； 簡單重覆性序列分子標誌 ； 遺傳歧異度 ； 群集分析 ； 主座標分析

並列摘要

Many kinds of varieties of Brassica oleracea L. has been popularly grown in the world as vegetables. Chinese kale is one of these vegetables which closely relates to primitive type Brassica oleracea L on taxonomy. The appearance of Chinese kale is various including not heading leaves, leaves curly or not etc., but generally distinguished by flower color , white or yellow. Southern Asia, Taiwan and China are main production area. There are two main kinds of product types in Taiwan include harvesting young plant as leafy vegetable (white flower type), or cutting flowered stalk to sale (yellow flower type). The cultured varieties in Taiwan mostly come from seed propagated by farmers and commercial F1 hybrid seed for leafy vegetable used. Therefore, it is benefit to conserve genetic diversity. It has been believe that Chinese kale is grow faster and more heat tolerance than broccoli and cauliflower. Nowadays, extreme weather frequently happened in Taiwan, therefore Chinese kale may be important breeding resource for heating tolerance of Brassica oleracea L. vegetables. Through revealing the genetic diversity and structure between Chinese kale accessions, that would be benefit for us to decide efficient breeding procedure.
The purpose of this study was to investigate the genetic diversity and genetic structure of Chinese kale accessions in Taiwan. We used 25 Chinese kale accessions and one commercial broccoli variety as a reference of related species. 7 appearance characters of 25 Chinese kale accessions was use to classified them by Principle component analysis. Furthermor, we use 20 SSR markers to amplify total 80 alleles of total 520 individuals, which means 20 individuals per accession, for genetic diversity analysis among and within accessions.
In the result of our study, Chinese kale accessions could classified generally into two groups by colors through the analysis of appearance character. It is the same conclusion of the studies in the past. On DNA level analysis, modified Roger’s distance among all accessions was 0.31 – 2.79 and was 0.31-2.36 among Chinese kale accessions. 25 Chinese kale accessions separated into two groups when coefficient on UPGMA phylogenic tree was 1.7 and similar result was on 3D plot of principle coordinate analysis. Furthermore, Fst value and genetic distance revealed that most accessions highly differenciated with each other, but several accessions were very close related. Close related accessions formed three sub-clusters respectively, which two were in yellow-flower cluster and one was in white-flower cluster. Furthermore, the diversity of yellow flower Chinese kale accession was larger the white flower accessions especially than commercial variety. We inferred that might be the result of open-pollination propagate habit of yellow Chinese kale accessions. After we realized the genetic similarity and structure among Chinese kale accessions, we could use resources and execute breeding procedure efficiently.

並列關鍵字

Brassica oleracea L. var. alboglabra ； SSR marker ； genetic diversity ； clustering analysis ； principle coordinate analysis

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