建立甘藍類作物品種鑑定之SSR分子標誌

Abstract

本研究利用65個品種，共98份來自7個變種的甘藍類蔬菜材料篩選出26個SSR分子標誌，在所有受試材料中均可擴增出產物。針對此98份材料進行基因座對偶基因分析，目的為建立一套可區分多數甘藍類作物品種的SSR分子標誌，為分子標誌實際應用於甘藍類作物品種鑑定建立基礎，並對各變種間親緣關係進行探討。26個分子標誌共獲得103個對偶基因，各基因座可獲得2至12個對偶基因，平均每個基因座含有3.96個對偶基因。分子標誌可偵測的基因型數量從最少2個至最多27個，平均每個分子標誌可以偵測到6.92個基因型。各基因座PIC值介於0.2635至0.8488，平均為0.5399。以此26個SSR分子標誌可以將本次受試品種均進行區分，各品種之間的遺傳距離介於0.098至0.8605之間，平均的遺傳距離為0.651。主座標分析的結果顯示前三個主成分解釋量分別為14.03 %、10.40 %以及6.78 %，其結果與群集分析結果相同，可將所有材料分為芥藍、青花菜、花椰菜、球莖甘藍、甘藍、抱子甘藍及羽衣甘藍七大群，而兩個青花筍品種則是歸類於青花菜類群中，與預期的七個栽培變種相符合。本研究亦對各變種的可能親緣關係進行探討，由遺傳距離及群集分析結果認為青花菜與花椰菜的親緣關係較近，芥藍與其他變種差異較大，前人研究亦認為芥藍未脫離甘藍類蔬菜的範圍。此外本次試驗在相同品種中發現有差異存在，若欲達成將分子標誌實際應用於品種鑑定的目標，需再進一步掌握品種內存在的變異性。

Twenty six SSR markers are screened by 65 cultivars of Brassica oleracea L. from seven botanical varieties, with 98 plants tested in total. The objectives of this study are to establish a set of SSR markers to distinguish the majority of cole crops (Brassica oleracea), and to serve as a base for including molecular markers as a tool in practical variety identification in cole crops. The genetic relationships between different varieties are also discussed. The 26 primer pairs amplified 103 alleles in total in all plants, the . number of alleles per locus of the selected makers ranged from 2 to 12, with an average of 3.96. Number of genotypes detected by each marker ranged from 2 to 27, with an average of 6.92.The PIC values of different markers range from 0.2635 to 0.8488, with an average of 0.5399.The 26 SSR markers could distinguish all cultivars in this study, the genetic distances between pair-wise cultivars range from 0.098 to 0.8605, with an average of 0.651. Principal coordinate analysis (PCoA) and UPGMA cluster showed similar results, all the 65 cultivars separated into seven groups as the taxonomy of botanical varieties, i.e. Chinese kale, broccoli, cauliflower, kohlrabi, cabbage, Brussels sprouts, and kale. Two Broccolini cultivars were classified to the broccoli group. According to the results of genetic distance and cluster analysis of different varieties, broccoli and cauliflower have the closest phylogenetic relationship, Chinese kale is the most distant variety from the other, however, still in same species. The result of intra-cultivar variations indicates that pre-knowledge of the genetic variability within a cultivar is needed before the application of molecular markers in actual variety identification in cole crops.