芝麻耐旱性的鉴定方法及关联分析

Identification Method of Drought Tolerance and Association Mapping for Sesame (Sesamum indicum L.)

为了解芝麻的耐旱性及获得与芝麻耐旱性相关的分子标记,在发芽期,采用不同浓度PEG 6000处理不同来源不同种皮颜色的10份芝麻品种,测定其形态特征和生理特征及各指标的差异显著性。结果表明,模拟芝麻干旱处理的最佳PEG6000浓度为15%;综合各项指标的主成分分析、最优回归方程分析及相关性分析表明,相对成苗率可以作为芝麻发芽期耐旱性鉴定的关键指标;利用上述方法对216份核心种质资源群体进行耐旱性鉴定,相对成苗率耐旱系数值位于12.15%~93.52%,平均为60.74%,变异系数为25.22,变异丰富且呈正态分布;资源群体的耐旱性指标值与608个多态性标记位点的关联分析,获得与芝麻发芽期耐旱性有显著关联的标记30个（P〈0.05）,解释率在1.99%~4.96%之间,平均2.84%。试验表明,相对成苗率是最适且最方便的耐旱性鉴定指标,适用于芝麻资源的耐旱性鉴定。

This research aims at understanding the drought tolerance of sesame germplasm and getting related molecular markers.Ten sesame varieties with different seed coat colors from separate origins were treated with PEG6000 with different concentrations,and the relative shoot length,relative fresh weight,relative seedling rate and the relative vigor index of the ten sesame varieties were investigated and analyses.The result showed 15% PEG6000 was proper for testing sesame drought tolerance.A comprehensive analysis based on principal component,regression equation and correlation showed that the relative seedling rate could be used as a key indicator to identify drought tolerance of sesame at germination stage.Using the method above,drought tolerance of 216 core collections during germination period was studied,the drought tolerance coefficients of sprout percentage were from 12.15% to 93.52%,the average was 60.74%,the coefficient of variation was 25.22,sprout abundant variation and accordant with normal distribution;together with marker screening,30 loci were significantly（P＆lt;0.05） associated with sesame drought tolerance at germination stage,explaining the phenotypic variation from 1.99% to 4.96%,with an average of 2.84%.So the relative seedling rate is the most suitable and most convenient drought tolerance index,which is suitable for drought tolerance identification of sesame resources.