辽河平原稻区粳稻耐热性综合评价

Comprehensive Evaluation of Heat Tolerance for Japonica Rice in Liaohe Plain Rice-growing Region

以辽河平原稻区适宜种植的20个粳稻品种为试验材料,采用农田开放式增温系统模拟增温。于水稻收获风干后测定有效穗数(X_(1))、每穗粒数(X_(2))、结实率(X_(3))、千粒重(X_(4))、产量(X_(5))、糙米率(X_(6))、精米率(X_(7))、蛋白质含量(X_(8))、直链淀粉含量(X_(9))和食味值(X_(10))指标,对比增温处理下不同粳稻品种10个性状指标的耐热系数,采用多元统计分析方法综合评价其耐热性,为建立有效的耐热评价体系提供依据。结果表明:除食味值外,增温处理使其他9个性状指标显著或极显著降低;基于耐热系数相关性分析表明,水稻性状各指标间存在不同程度的相关性,应用主成分分析将10个单项指标降维转化为4个相互独立的综合指标,其贡献率分别为34.816%、19.265%、15.636%和10.605%,累计贡献率达80.322%;利用隶属函数法计算耐热性综合评价值(D_(i)值),D_(i)值越大代表耐热性越强,‘盐粳456’耐热性最强,‘沈农016’耐热性最差;20个粳稻品种按耐热性强弱可划分为3类,第Ⅰ类为耐热型7个品种,第Ⅱ类为中度耐热型6个品种,第Ⅲ类为热敏感型7个品种。

To analyze the heat tolerance of japonica rice in Liaohe plain rice-growing region,and establish an effective evaluation system of heat tolerance,20 main varieties of japonica rice suitable for cultivating over this region were selected and planted under simulated temperature increase using the free air temperature increase system.The heat tolerance of different japonica rice varieties was comprehensively evaluated by multivariate statistical analysis methods based on the heat tolerance coefficients of 10 rice trait indicators,the effective panicle number(X_(1)),grain number per spike(X_(2)),seed setting rate(X_(3)),1000-grain weight(X_(4)),yield(X_(5)),brown rice rate(X_(6)),milled rice rate(X_(7)),protein content(X_(8)),amylose content(X_(9)),and taste value(X_(10))after harvesting and air-drying the rice.The results showed that the trait indicators except taste value were significantly or extremely reduced under the warming.Correlation analysis based on heat tolerance coefficients revealed different degrees of association between rice trait indicators.Principal component analysis condensed the 10 individual indicators into 4 mutually independent comprehensive indicators.The 4 comprehensive indicators had contribution rates of 34.816%,19.265%,15.636%,and 10.605%,respectively,giving a cumulative contribution rate of 80.322%.The comprehensive evaluation values of heat tolerance(D_(i) value)were calculated using the membership function method.The higher the D_(i) value,the stronger the heat tolerance.The heat tolerance of'Yanjing 456'was the strongest and that of'Shennong 016'was the worst.The 20 japonica rice varieties were classified into three categories based on their heat tolerance:the first category comprised 7 heat-tolerant varieties,the second category included 6 moderately heat-tolerant varieties,and the third category consisted of 7 heat-sensitive varieties.