不同油麦菜品种萌发期耐热指标筛选及耐热性评价

Screening of Indexes for Heat Tolerance Assessmentduring Germination in Various Lettuce Varieties

为筛选油麦菜萌发期耐热性的鉴定指标,初步构建耐热性评价体系,为生产上快速筛选耐热的油麦菜品种及提高耐热油麦菜育种效率提供依据,本研究以15个油麦菜品种为试材,以筛选出的35℃高温胁迫条件为基础,通过设置正常和35℃高温2个处理,测定不同油麦菜品种萌发期的7个形态指标,并计算耐热系数;以各指标的耐热系数为基础,利用相关性分析、主成分分析、隶属函数分析、逐步回归分析、聚类分析等方法对各参试油麦菜品种萌发期的耐热性进行综合评价并对耐热指标进行筛选,并结合各参试油麦菜品种田间耐热性对萌发期的耐热性鉴定结果进行验证。结果表明,35℃高温处理后,不同品种的发芽率、发芽势、发芽指数、活力指数、芽根比、芽粗及鲜质量等均显著下降。对这7个单项指标进行多元统计综合评价及相关性分析发现,除芽根比外,其余单项指标耐热性系数之间存在极显著正相关。主成分分析从这7个指标提取出2个相互独立的主成分,可概括参试油麦菜品种萌发期耐热性原始信息量的90.70%。通过隶属函数分析得出耐热性综合评价值(D值),并进行排序得出‘脆香油麦菜’耐热性最强、‘圣美紫油麦菜’耐热性最差。通过聚类分析将15个参试品种分为耐热型、中等耐热型、不耐热型3类,综合主成分分析和逐步回归分析的结果得出,发芽率、芽根比、活力指数为油麦菜萌发期耐热性鉴定重要指标。各参试品种萌发期耐热性鉴定结果与田间成株期鉴定结果基本一致。

To assess the heat tolerance of different lettuce varieties during the germination stage,methods such as principal component analysis,subordination function analysis,stepwise regression analysis,cluster analysis and others were performed.The heat tolerance indexes were identified,and the results of heat tolerance during the germination period were verified by comparing them with the heat tolerance observed in the field for the tested lettuce varieties.The results showed that after 35℃high temperature treatment,the germination percentage,germination potential,germination index,vigor index,ratio of bud to root,bud diameter and fresh mass of different varieties decreased significantly.Multivariate statistical comprehensive evaluation and correlation analysis of the seven individual indicators showed that there was a very significant positive correlation between the heat tolerance coefficients of other individual indicators except for the ratio of buds to roots.The principal component analysis extracted two independent principal components from these seven indicators,which could sum up 90.70%of the original information of heat tolerance of the tested lettuces at the germination stage.The comprehensive evaluation value of heat tolerance(D value)was obtained through the analysis of membership function,and the results showed that the heat tolerance of‘Cuixiang’was the strongest,while‘Shengmeizi’was the worst.By cluster analysis,15 varieties were divided into three types:heat tolerance,heat intolerancee,and medium heat tolerance.The results of principal component analysis and stepwise regression analysis showed that germination percentage,shoot root ratio,and vigor index were important indicators for heat tolerance identification of rapeseed during germination.The heat tolerance identification results for all tested varieties during the germination stage were generally consistent with those obtained at the mature field stage.