热带水稻种质资源全生育期耐盐性鉴定与评价

Identification and evaluation for salt tolerance of tropical rice germplasm resources in whole growth period

【目的】明确热带水稻种质资源全生育期耐盐性鉴定的适宜浓度和关键指标,筛选耐盐热带水稻种质资源,为开展热带水稻耐盐机制研究和品种选育提供理论依据。【方法】设盐(NaCl)浓度为0(CK)、0.3%和0.6%3个处理,对23份参试水稻种质资源进行全生育期盐胁迫试验,选用9个耐盐指标,采用多元统计分析方法开展全生育期耐盐性鉴定与评价。【结果】方差分析和相关分析结果显示,0.6%NaCl胁迫下热带水稻种质资源的成活率、单株穗数、主穗总粒数、千粒重和单株产量显著低于CK(P<0.05,下同),丙二醛和钠含量显著高于CK,大多数耐盐指标间存在显著或极显著(P<0.01)相关性,指标间联系较紧密,因此确定热带水稻全生育期耐盐性鉴定的适宜NaCl浓度为0.6%。采用主成分分析法对参试热带水稻种质资源耐盐性综合评价值(D)进行排序,其中有6份热带水稻种质资源(ST007、W25S/ST003、ST017、ST018、ST019和ST020)的D值在0.70以上,耐盐性较强。根据D值进行聚类分析,可将参试热带水稻种质资源划分为三大类群,筛选出6份耐盐性较强的热带水稻种质资源,聚类结果与D值排序基本一致。不同类群热带水稻种质资源的耐盐性主要表现为成活率、单株穗数、单株产量和主穗总粒数的差异,进一步的逐步线性回归分析结果表明,主穗总粒数、成活率和单株穗数可作为热带水稻全生育期耐盐性评价的关键指标。【结论】热带水稻全生育期耐盐性鉴定的适宜NaCl浓度为0.6%;筛选出主穗总粒数、成活率和单株穗数3个关键指标建立回归方程用于热带水稻全生育期耐盐性评价;获得6份耐盐性较强的热带水稻种质资源,分别为ST007、W25S/ST003、ST017、ST018、ST019和ST020。

【Objective】The purpose of the study was to identify the appropriate concentration and key indicators for salt tolerance in tropical rice germplasm resources in whole growth period,to screentropical rice germplasm resources with strong salt tolerance,and to provide theoretical support for carrying out research on salt tolerance mechanism and variety breeding of tropical rice.【Method】Three treatments with salt(NaCl)concentrations of 0(CK),0.3%and 0.6%were set to carry out salt stress experiments on 23 tropical rice germplasm resources in whole growth period.Nine salt tolerance indicators were selected,and multivariate statistical analysis method were used to carry out the identification and evaluation salt tolerance in whole growth period.【Result】Under 0.6%NaCl stress,the results of analysis of variance and correlation analysis showed that the survival rate,panicle number per plant,total grains per main spike,1000-grain weight,and yield per plant of tropical rice germplasm resources were significantly lower than that of CK(P<0.05,the same below),while malondialdehyde and sodium contents were significantly higher than CK.There were significant or extremely significant(P<0.01)correlations between most of the salt tolerance indicators,and the relationship between indicators was relatively close.Therefore,the appropriate NaCl concentration for identifying salt tolerance of tropical rice in whole growth period was determined to be 0.6%.The principal component analysis method was used to rank the comprehensive evaluation values(D)of salt tolerance of the tested tropical rice germplasms.Among the tested materials,six tropical rice germplasm resources(ST007,W25S/ST003,ST017,ST018,ST019 and ST020)had a D value above 0.70,indicating strong salt tolerance.Using cluster analysis based on the D value,the tested tropical rice germplasm resources could be divided into three major groups,and six tropical rice germplasm resources with strong salt tolerance were selected.The clustering results were basically consistent with the D value rank.The salt tolerance of tropical rice germplasm resources in different groups was mainly manifested as differences in survival rate,panicle number per plant,yield per plant,and total grains per main spike.Further stepwise linear regression analysis results indicated that the total grains per main spike,survival rate and panicle number per plant could be used as key indicators for evaluating salt tolerance of tropical rice in whole growth period.【Conclusion】The appropriate NaCl concentration for identifying salt tolerance of tropical rice in whole growth period is 0.6%.Three key indicators(the total grains per main spike,survival rate and panicle number per plant)are selected to establish regression equations for evaluating salt tolerance of tropical rice in whole growth period.Six tropical rice germplasm resources with strong salt tolerance are obtained,namely ST007,W25S/ST003,ST017,ST018,ST019 and ST020.