黄瓜耐热性芽苗期鉴定指标筛选及预测方程的建立

Screening of identification indexes at seed germination stage and establishment of the forecast equation for cucumber hot tolerance

【目的】研究高温胁迫下黄瓜芽苗期的主要生物学性状,筛选芽苗期黄瓜耐热鉴定的形态指标。【方法】以25℃为对照(CK)温度,以4个已知耐热性的黄瓜品系种子为试材,在不同高温(35,38,42℃)下发芽6d后,测定芽苗形态指标,并进行主成分分析和回归分析。【结果】38℃高温发芽条件下,黄瓜幼苗的全鲜质量(X1)、去子叶鲜质量(X2)、根鲜质量(X3)、下胚轴长(X4)、活力指数(X5)与黄瓜品系耐热性的相关性比35和42℃下更密切,可作为耐热种质筛选的指标;主成分分析表明,第一、二主成分对耐热性评价的贡献率分别为89.03%和9.86%;通过回归分析建立了黄瓜耐热性预测方程。【结论】在38℃高温条件下发芽后6d测定的X2和X5,可作为黄瓜耐热性芽苗期鉴定的简易指标,利用回归方程Y=-0.347 3+0.245 0 X2+0.073 5 X5,可以预测黄瓜品种资源的耐热性。

【Objective】 The biological characteristics at germination and sprouting stage were studied to screen hot tolerance identification morphologic indexes for cucumber.【Method】 Taking the 4 hot-tolerance known straits of cucumber as the test material and 25 ℃ as the temperature control,the main morphological indexes of cucumber were investigated under different high temperature（35 ℃,38 ℃,42 ℃） conditions 6 days after germination.The principal component analysis and regression analysis were made according to these indexes.【Result】 The whole-plant fresh weight（X1）,fresh weight of plant without cotyledon（X2）,root fresh weight（X3）,hypocotyl length（X4） and vigor index（X5） showed significant correlations with hot-tolerance,which were suggested to be the reliable screening indexes to identify hot tolerance variety.The first and second principal component contributed 89.03% and 9.86% to the hot tolerance of cucumber,respectively.A regressive equitation was established to access cucumber hot tolerance.【Conclusion】 The indexes X2 and X5 of cucumber germinated at 38 ℃ for 6 days are thought to be the simple indexes and the regressive equitation Y=-0.347 3＋0.245 0X2＋0.073 5X5 is selected to forecast the hot tolerance of cucumber germplasm at germination and sprouting stage.