基于耐盐指数STTI的柳枝稷F2代群体耐盐性分析

Salt Tolerance Analysis of F2 Generation Population of Switchgrass Based on Salt Tolerance Trait Index STTI

杂交育种是植物耐盐新品种选育的重要途径之一,而对杂种F2代耐盐能力的综合评价至关重要。本研究以柳枝稷(Panicum virgatum)F2代的53个单株为研究对象,以亲本材料Alamo、Dacotah和F1代的DA90、DA120为参照,采用沙培法,在250 mmol/L NaCl的胁迫条件下进行耐盐性分析。在盐处理24 d后,测定电解质外渗率(EL)、相对含水量(RWC)、干重(DW)、净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs),通过对耐盐指数STTI进行主成分分析和隶属函数分析,结果表明:柳枝稷F2代的不同材料间耐盐能力存在显著差异。亲本Alamo的耐盐能力较高,亲本Dacotah的耐盐能力较差,F1代的DA90和DA120的耐盐能力中等,F2代的耐盐性有明显分离,表现在6份F2代材料的耐盐能力强于耐盐亲本Alamo,7份F2代材料的耐盐能力弱于不耐盐亲本Dacotah。主成分分析结果得到3个主成分,累计贡献率达87.47%。聚类分析将57份参试材料分为5类,分别代表不同耐盐程度的类群。隶属函数分析表明,F2代的39、45、27、48、35、53、7号耐盐性最强,该结果为柳枝稷耐盐相关性状的遗传图谱构建、QTL定位、柳枝稷耐盐育种奠定了基础。

Cross-breeding is one of important ways to breed new varieties of plants, and it is essential to analyze the performance of hybrid F2 generation. In this study, 53 F2 generation plants of Panicum virgatum were used as the research material. The parents Alamo, Dacotah and F1 generation DA90 and DA120 were used as the reference. Salt tolerance performance was evaluated with sand culture method under 250 mmol/L NaCl stress conditions. The electrolyte leakage rate(EL), relative water content(RWC), dry weight(DW), net photosynthetic rate(Pn), transpiration rate(Tr), stomatal conductance(Gs) were measured after 24 days of salt treatment. Principal component analysis and membership function analysis of salt tolerance trait index(STTI) showed that there were significant differences in salt tolerance between different F2 plants. Parent Alamo was relatively salt tolerant, Dacotah was sensitive to salt, DA90 and DA120 had moderate salt tolerance, and the F2 generation had significant segregation in salt tolerance. Six F2 plants were better in salt tolerance than Alamo. Seven F2 plants were worse in salt tolerance than Dacotah. Three principal components with a cumulative contribution rate of 87.47% were selected by the principal component analysis. The 57 test plants were divided into five categories by cluster analysis. Membership function indicated that F2 generations 39, 45, 27, 48, 35, 53 and 7 had higher salt tolerance, which would build up a good basis for the construction of the genetic map of the salt tolerance-related traits, the QTL mapping and the salt-tolerant breeding of switchgrass.