基于主成分分析和隶属函数的谷子全生育期耐旱性鉴定

Identification of drought tolerance in foxtail millet during its entire growth period based on principal component analysis and membership function

优异耐旱种质资源鉴定及耐旱指标筛选研究对于挖掘耐旱基因和提高耐旱育种效率具有重要作用。2019—2020年以30份谷子种质为试材,采用随机不完全区组设计(alpha-格子设计),设干旱胁迫(DS)和正常供水(CK)2个处理,考察了谷子农艺性状的耐旱系数,通过综合评价指标耐旱性度量值D对供试谷子材料的耐旱性进行鉴定。联合方差分析表明:土壤水分环境和基因型显著影响谷子农艺性状,而且基因型与土壤水分环境的互作显著影响谷子生长性状,但对产量性状的影响不显著(千粒重除外)。t测验结果表明干旱胁迫效果显著(千粒重除外)。主成分分析将11个单项耐旱评价指标转化为3个相互独立的综合指标,方差累计贡献率为81.27%。第一主成分相当于5.866个原始指标的作用,可以解释53.327%的方差,其中株高、倒二叶叶面积、茎叶干重、穗长、穗重、穗粒重指标载荷系数绝对值较大;第二主成分主要反映的是穗颈长和穗粒数指标;第三主成分中起主要作用的是主茎节数、千粒重和产量指标。依据D值非加权组平均法聚类分析,将供试谷子材料耐旱性分为5类。判别分析表明株高和穗重可作为谷子全生育期耐旱性鉴定首选指标。基于主成分分析和隶属函数确定耐旱性评价指标D值,通过D值可对谷子全生育期耐旱性进行有效可靠的鉴定。

This study aimed to screen drought tolerance materials and indices in foxtail millet germplasm resources to explore drought tolerance genes and improve the efficiency of drought tolerance breeding.A field experiment was conducted using a randomized incomplete block design(alpha-lattice design)and repeated thrice in 2019-2020.Each experiment was consisted of 30 foxtail millet genotypes treated under drought stress(DS)and normal water supply(CK).The agronomic traits and drought tolerance coefficient of the genotypes were assessed during the entire growth period.The drought tolerance of foxtail millet was identified by the comprehensive evaluation index D.Combined analysis of variance showed that soil water environment and genotype significantly affected the indices.Besides,the interaction between genotype and soil water environment significantly affected the growth traits of foxtail millet,but not yield traits(except 1000-grain weight).The results of t-test showed that the effect of drought stress was significant(except 1000-grain weight).Principal component analysis transformed eleven single drought tolerance evaluation indices into three independent comprehensive indices,and the cumulative contribution rate of variance reached 81.27%.The first principal component was equivalent to 5.866 original indices,which explained 53.327%variance,in which the absolute values of load coefficients of plant height,top second leaf area,dry weight of stem and leaf,spike length,spike weight and grain weight per spike were larger.The second principal component mainly reflected the top node length and kernels per spike.Stem node number,1000-grain weight and yield played major role in the third principal component.According to the cluster analysis of the D-value unweighted pair-group method with arithmetic means,the drought tolerance of foxtail millet was divided into five categories.Discriminant analysis showed that plant height and spike weight per plant should be used as indices for drought tolerance identification in foxtail millet.Based on principal component analysis and membership function,the comprehensive evaluation index D of drought tolerance of several agronomic traits should be used to identify drought tolerance during the entire growth period in foxtail millet.