凉粉草种质资源主要光合性状和农艺性状的遗传变异分析及综合评价

Genetic variation analysis and comprehensive evaluation on main photosynthetic traits and agronomic traits of Mesona chinensis germplasm resources

[目的]对凉粉草种质资源的主要光合性状和农艺性状进行遗传变异分析及综合评价,为凉粉草种质资源筛选及品种选育提供参考依据。[方法]以来源于不同地区的8份凉粉草种质为试验材料,测定其主要光合性状和农艺性状,采用遗传变异、主成分分析和聚类分析对8份凉粉草种质进行遗传变异分析及综合评价。[结果]8份凉粉草种质光合性状变异系数为6.53%~26.94%,广义遗传力为48.47%~99.14%;农艺性状变异系数为16.26%~36.44%,广义遗传力为69.85%~99.63%。对8份凉粉草种质的20个性状进行主成分分析,提取到3个主成分,累积贡献率达89.145%,基本解释20个性状中的大部分信息。其中第一主成分反映的是相对叶绿素含量(SPAD)、细胞间CO_(2)浓度(C_(i))、蒸腾速率(T_(r))、水分利用率(WUE)和气孔限制值(L_(s)),第二主成分反映的是叶绿素含量、类胡萝卜素含量和净光合速率(P_n),第三主成分反映的是叶宽、叶片面积和茎粗。通过综合得分初步筛选出X2、X3和X4为凉粉草优良种质。聚类分析将8份凉粉草种质划分为三大类群:第Ⅰ类群表现为叶片大,节间长,主茎粗且长,光合能力强,产量高;第Ⅱ类群表现为叶片较大,主茎短,产量低;第Ⅲ类群表现为叶片小,主茎较长,SPAD值高。[结论]8份凉粉草种质主要光合性状和农艺性状遗传变异较大,其中X2、X3和X4种质综合表现较好,可作为杂交优良亲本。在品种选育早期应把SPAD、C_(i)和T_(r)等高遗传力性状纳入到品种筛选的目标性状。

[Objective]The genetic variation analysis and comprehensive evaluation of the main photosynthetic and agronomic traits of Mesona chinensis germplasm resources were carried out to provide a reference for M.chinensis germplasm resources screening and variety breeding.[Method]The main photosynthetic and agronomic traits of 8 M.chinensis germplasms from different regions were determined.Genetic varia-tion analysis,principal component analysis and cluster analysis were used to analyze and evaluate the genetic variation of 8 M.chinensis germplasms from dfferent regions.[Result]For the 8 M.chinensis germplasms,the coeficient of variation of photosynthetic characters was 6.53%-26.94%,and the general heritability was 48.47%-99.14%,the variation coefficient of agronomic traits was 16.26%-36.44%,and the general heritability was 69.85%-99.63%.Three principal components were extracted from 20 traits of M.chinensis by principal component analysis,and their cumulative contribution was 89.145%,which explained most of the information of 20 traits.The first principal component was related to relative chlorophyll content(SPAD),intercellular CO_(2) concentration(C_(i)),transpiration rate(T_(r)),water utilization rate(WUE),stomatal limit value(L.),the second principal component was related to chlorophyll content,carotenoid content and net photosynthetic rate(P.),and the third principal component was related to leaf width,leaf area and stem diameter.X2,X3 and X4 were selected as excellent M.chinensis germplasm.By cluster analysis,8 M.chinensis germplasm were divided into 3 groups:The I group showed large leaves,long internodes,thick and long main stems,strong photosynthetic capacity and high yield.Group II showed large leaves,short main stem and low yield.Group Ⅲ showed small leaves,long main stem and high SPAD value.[Conclusion]The genetic variation of the main photosynthetic and agronomic traits of the 8 M.chinensis germplasm is great,and X2,X3 and X4 germplasms have better comprehensive per-formance and could be used as excellent hybrid parents.High heritability traits such as SPAD,C_(i)and T_(r)should be included in the target traits of variety screening in the early stage of breed selection.