西藏玉米地方品种表型多样性分析及类群划分

为了解西藏玉米地方品种多样性及类群特点,进一步挖掘优异基因资源,采用多年重复实验,对179份西藏玉米地方品种的36个农艺性状进行多样性鉴定,利用离差平方和方法分年进行聚类分析,分析了西藏玉米地方品种的表型特征,结果表明:西藏玉米地方品种存在较高水平的多样性,36个农艺性状中有20个性状的多样性指数达2.0以上,其中粒色的多样性指数2.27,体现西藏玉米地方品种粒色丰富的突出特点。基于36个性状的聚类分析结果将西藏玉米地方品种分为3大类群,即晚熟高秆型、高寒早熟型和干热河谷硬粒型。其中干热河谷硬粒类群是西藏玉米传统主栽地方品种类型,综合性状与国内其他族群不同,属西藏特色中熟硬粒玉米。全面分析表明,西藏玉米地方品种表现较高的表型多样性水平,具有重要的演化地位,为西藏是我国玉米的重要传入路径提供理论依据。基于综合性状所划分的3大玉米类群具有不同的表型特征与育种利用价值,作为该区玉米地方品种的保护和开发利用理论基础。

Phenotypic diversity and group classification of maize landraces in Tibet

The objective of this study was to evaluate the phenotypic characterization and reveal group classification of Tibet maize landraces.One hundred and seventy-nine maize landrace varieties from Tibet were used to carry out phenotypic studies.All materials were planted for a 2-year phenotypic characterization of 36 traits.Shannon-Weaver diversity index was calculated based on the phenotypic estimates.Euclidean distance among the 179 maize landraces was calculated based on phenotypic traits,on which the ward cluster analysis was carried out.The result showed that high level of diversity was observed in the accessions from Tibet maize region.The Shannon-Weaver diversity indices of 20 agronomic traits were more than 2.0 in 36 agronomic traits,among which the especially kernel color reached 2.27 reflecting the characteristics of rich color of accessions from Tibet maize region.The 179 maize landraces were separated into 3 groups by the ward clustering analysis,including late-maturing with high stem genotype,early-maturing genotype from alpine region,hard kernel genotype from dry-hot valley region.The third genotype was the main local germplasm with Tibet characteristics from Tibet maize tradition main plant area.In general,there high level of phenotypic diversity was existed among Tibet maize landrace varieties;Diversity was of great importance in analyzing the ecological evolution,which provides theoretical basis for Tibet as an important afferent path of maize in China.Phenotypic summary statistics revealed that landraces of each group possessed a distinct phenotypic characterization indicating high potential utility of these germplasm in maize breeding and cultivars improvement.