糯玉米萌发期耐低温品种资源的综合评价

为构建不同糯玉米品种萌发期耐低温评价体系,以48个糯玉米品种为试验材料,测定低温胁迫下糯玉米的10个萌发及生长指标,通过主成分分析法、隶属函数法、聚类分析和回归分析,对糯玉米品种耐低温性进行综合评价与分类。结果表明,主成分分析将10个测定指标转化为根系生长因子和种子萌发因子2个相互独立的综合指标,建立了糯玉米耐低温综合得分模型Y=0.647 7Y₁+0.144 2Y₂（其中,Y₁、Y₂为2个主成分,Y₁代表的主要指标包括相对根干重、相对根表面积、相对根体积、相对根长,反映低温胁迫下糯玉米根系生长的状态;Y₂代表的主要指标包括相对苗干重、相对发芽率、相对活力指数、相对发芽势,反映低温胁迫下糯玉米的萌发情况）。通过隶属函数法对48个糯玉米品种的耐低温能力进行排序,筛选出5个耐低温能力较强的品种,依次为‘润彩糯686’‘景坡82’‘润糯175’‘润糯605’和‘天贵糯932’。聚类分析将48个糯玉米品种划分成4个类群。回归分析表明,相对根干重、相对苗长、相对发芽势、相对发芽率、相对苗干重和相对根表面积可作为糯玉米耐低温评价的重要指标。多方法关联分析的综合评价方法可对不同耐低温能力的糯玉米品种进行有效筛选分类,为糯玉米耐低温评价及耐低温种质资源的筛选提供参考。

Comprehensive Evaluation of Low Temperature Tolerance of Waxy Maize Varieties at Germination Stage

In order to construct evaluation system of different waxy maize varieties during germination for low temperature tolerance, 48 waxy maize varieties were used as test materials to measure 10 indicators on germination and growth under low temperature stress. And the low temperature tolerances of waxy maize varieties were comprehensively evaluated by principal component analysis, membership function method, cluster analysis and regression analysis. The results showed that 10 measurement indexes were transformed into 2 independent comprehensive indexes by principal component analysis, including root growth factor and seed germination factor. The comprehensive score model of low temperature tolerance of waxy maize was established, Y=0.647 7Y₁+0.144 2Y₂, where Y₁ and Y₂ were scores of the two principal components, respectively. Y₁ included relative root dry weight, relative root surface area, relative root volume, and relative root length, which could reflect the state of root growth of waxy maize under low temperature stress; and Y₂ included relative seedling dry weight, relative germination rate, relative vitality index, and relative germination potential, which could reflect the germination of waxy maize under low temperature stress. The 48 waxy maize varieties were ranked by affiliation function method for low temperature tolerance, and the five varieties with the strong low temperature resistance were screened, including ‘Runcainuo 686’‘ Jingpo 82’‘Runnuo 175’‘Runnuo 605’ and ‘Tianguinuo 932’. The cluster analysis classified 48 waxy maize varieties into 4 groups. The regression analysis showed that the relative root dry weight, relative seedling length, relative germination potential, relative germination rate, relative seedling dry weight and relative root surface area could be used as important indicators for the evaluation of low-temperature tolerance of waxy maize. The comprehensive evaluation of multiple methods could effectively screen and classify waxy maize varieties with different low-temperature tolerances, which provided reference for the evaluation of waxy maize low-temperature tolerance and the screening of low-temperature tolerance germplasm resources.