甘蓝型油菜耐盐相关性状的主成分分析及综合评价

Principal Component Analysis and Comprehensive Evaluation on Salt Tolerance Related Traits in Brassica napus L.

摘要: 目的：通过对种子萌芽期盐胁迫下甘蓝型油菜耐盐相关指标的研究，筛选和鉴定甘蓝型油菜耐盐种质资源。方法：通过浓度梯度实验对中双11号油菜种子萌芽期进行盐胁迫培养，测定种子的发芽率，确定最佳盐胁迫浓度为1.2% NaC1。在此浓度下，对88份不同遗传背景的甘蓝型油菜在盐胁迫处理下进行发芽试验，同时以去离子水为对照，播种后7天测定种子的发芽率、根长、整株鲜重和发芽势，以盐胁迫下各性状相对指数作为衡量耐盐性指标，利用主成分分析、隶属函数分析及聚类分析对其进行耐盐性综合评价。结果：在1.2% NaC1胁迫下，根长受盐胁迫影响程度最大，而发芽率受盐胁迫影响最小。各耐盐指标间的相关性分析表明，除了根长与发芽率之间无显著相关外，其他指标两两之间均存在显著正相关。通过对各耐盐指标进行主成分分析，最终确定各主成分贡献率及各指标对耐盐综合指标的贡献率。进一步应用隶属函数分析法对88个材料各主成分进行了综合评估并进行聚类分析，将88个基因型划分为高度耐盐、中度耐盐、不耐盐和盐敏感型4类，其中高度耐盐基因型有8个，中度耐盐21个，低度耐盐33个，盐敏感型26。根据综合评价结果，筛选出最耐盐品种为SW190。结论：可利用主成分分析、隶属函数分析和聚类分析对甘蓝型油菜种子萌芽期耐盐性进行分类和综合评价，筛选甘蓝型油菜耐盐种质。

Abstract: Objective: To identify and screen the salt tolerance resource in Brassica napus L., four indexes of salt tolerance related traits during seed germination stage were studied. Method: In this study, 1.2% NaCl was determined as the optimal salt stress concentration by the concentration gradient experiment on Zhongshuang 11. Subsequently, 88 Brassica napus varieties with different genetic background were evaluated for salt tolerance under the conditions of normal water supply and salt stress with 1.2% NaCl. Four indexes related to salt stress tolerance, including relative germination rate, relative root length, relative fresh weight and relative germination potential were measured. Principal component analysis, membership function value analysis and clustering analysis were used to evaluate the salt tolerance of 88 genotypes. Result: The results showed that salt stress has less influence on germination rate. However, it has larger influence on root length. By the principal component analysis on the four indexes, contribution rate of each principal component was obtained. The 88 materials were evaluated by membership function value analysis and for cluster analysis. Eighty-eight genotypes were clustered into 4 different levels of tolerance. 8, 21, 33 and 26 lines were classified as strong salt tolerant, medium tolerant, low tolerant and sensitive under salt stress during seed germination stage, respectively. Based on the results of comprehensive analysis, SW190 was determined to possess the strongest salt tolerance. Conclusion: It is feasible to comprehensively evaluate the salt tolerance of B. napus at the stage of seed germination by principal component analysis, membership function value analysis, and clustering analysis, which could be used to screen germplasm lines of B. napus for salt tolerance.