粳稻种质资源苗期耐盐性综合评价与筛选

Comprehensive Evaluation and Selection of Rice(Oryza sativa japonica)Germplasm for Saline Tolerance at Seedling Stage

为鉴定和评价粳稻种质资源苗期耐盐性,利用125 mmol/L NaCl盐胁迫对165份粳稻种质资源进行处理,测定耐盐级别、叶片伤害百分率、苗高、根长、SPAD、地上部鲜重、根鲜重、地上部干重和根干重,计算地上部含水量和除耐盐级别、叶片伤害百分率之外各性状的相对指标。结果表明:耐盐级别与相对苗高、相对SPAD、相对地上部鲜重、相对根鲜重、相对地上部干重、相对根干重、相对植株干重和地上部含水量均呈极显著正相关,与叶片伤害百分率和相对根冠比呈极显著负相关。通过主成分分析将12个评价指标转换为5个主成分,累计贡献率为86.473%,应用隶属函数和权重,获得了客观评价粳稻种质资源苗期耐盐性的综合评价值D。筛选到Bertone、长白26、伊粳12号、宁资629和小琥板稻5个苗期综合耐盐性强的种质。通过聚类分析将165份粳稻种质资源划分为4类,第Ⅰ类群主要由盐敏感种质构成,第Ⅱ类群主要由弱耐盐种质构成,第Ⅲ类群仅包含1份盐敏感种质,为苏选2,第Ⅳ类群是以弱耐盐和耐盐种质为主的混合类群。结合主成分和逐步回归分析,确定耐盐级别、相对根长、相对地上部干重、相对根干重和地上部含水量5个指标可作为粳稻种质资源苗期耐盐性鉴定的重要指标,本研究结果可为耐盐水稻资源筛选及鉴定提供理论依据。

In order to identify and assess salt tolerance of japonica rice germplasm at seedling stage,salt stress treatment,by using Yoshida culture solution containing 125 mmol/L NaCl,was applied for analyzing 165 japonica rice germplasm accessions.Several parameters including salt tolerance score,leaf damage percentage,seedling height,root length,SPAD value,shoot fresh weight,root fresh weight,shoot dry weight and root dry weight as well as shoot water content were measured.The results revealed significant positive correlations between salt tolerance score and relative seedling height,relative SPAD value,relative shoot fresh weight,relative root fresh weight,relative shoot dry weight,relative root dry weight,relative plant dry weight and shoot water content.Meanwhile,salt tolerance score was found to be significantly negatively correlated with leaf damage percentage and relative root-shoot ratio.Principal component analysis(PCA)with 12 evaluation index suggested five major components,with a cumulative contribution rate of 86.473%.With membership functions and index weight method,a comprehensive evaluation value D for objectively assessing the salt tolerance of japonica rice germplasm resources at seedling stage was obtained.Subsequently,five rice germplasm(Bertone,Changbai 26,Yijing 12,Ningzi 629 and Xiaohubandao)showing the top five D value at the seedling stage were selected.Furthermore,cluster analysis assigned 165 japonica rice germplasm into four groups.For examples,salt-sensitive germplasm accessions were mainly found in group-I;the germplasm genotypes showing weak salt-tolerant were resided in group-II;the group-III contained only one salt sensitive cultivar(Suxuan 2);the group-IV was largely consisted of weak salt-tolerant and salt-tolerant germplasm genotypes.Taken together,five parameters including salt tolerance score,relative root length,relative shoot dry weight,relative root dry weight and shoot water content,were deployed as important indicators,in order to identify salt-tolerant japonica rice germplasm at seedling stage.The results gained from this study?provide a theoretical foundation for screening and identifying the salt-tolerant rice germplasm resources.