中国玉米地方品种的种族划分及其特点

Racial Classification and Characterization of Maize Landraces in China

【目的】系统了解中国玉米地方品种多样性及所包括的种族类型,是研究作物生态分化、进一步挖掘优异基因资源、实现育种持续发展的重要基础性工作。【方法】以能代表中国地方品种多样性的核心种质中所包括的730份地方品种为材料,采用随机区组设计,对研究材料进行包括生育期性状在内的31个农艺性状进行了多年鉴定,基于这些表型性状的调查值,进行主成份分析以及聚类分析,依据聚类分析所揭示的表型性状计算730份玉米品种的欧式距离(Euclidean distance),进而对中国玉米地方品种进行种族划分。【结果】主成份分析结果表明,前13个主成份可以囊括所有表型的86.2%遗传信息,基于这13个主成份所揭示的11个表型性状的Neighbor-Joining(NJ)聚类结果表明,中国玉米可以划分为9个种族,即西南黄色硬粒种族、西南白色硬粒种族、北方黄色硬粒种族、北方白色硬粒种族、西南马齿种族、北方马齿种族、衍生种族、南方糯质玉米种族以及爆裂玉米种族。【结论】中国的玉米地方品种对本土具有良好的适应性与自身的特点,基于广泛地理来源的地方品种,所划分的9个玉米种族各自具有不同的表型特征与育种利用价值,但与南美及美国所拥有的玉米多样性相比,中国地方品种的遗传基础显得相对狭窄。引进和利用国外不同类型地方品种,依然具有重要的科学与实践意义。

[ Objective ] Systematic and complete information of diversity and types of races of Chinese maize landraces is of great importance in mining the elite alleles, analyzing the ecological evolution, and achieving the continuable development in maize breeding. The objective of this study was to reveal the races of Chinese maize landraces for the first time, and to evaluate the phenotypic characterization of each race as well. [Method] Seven hundred and thirty maize landrace accessions from the core collection of conserved in the China National Genebank were used to carry out the racial classification of Chinese maize landraces. All these materials were planted for a 2-year phenotypic characterization of 31 traits according to a randomized block design with three replications. Principal component analysis of all these 31 phenotypic traits determined 11 main traits for the racial classification of these landraces. Euclidean distance among the 730 maize landraces was calculated based on these 11 phenotypic traits, on which the Neighbor-Joining （NJ） clustering analysis was carded out. [Result] Revealed by the NJ clustering analysis, the 730 maize landraces were separated into 9 races, including southwestern yellow flints, southwestern white flints, northern yellow flints, northern white flints, southwestern dents, northern dents, derived race, southern waxy race, and pop corn race. [Conclusion] Phenotypic summary statistics revealed that landraces of each race covered a widely geographical distribution and possessed a distinct phenotypic characterization, which indicated a good adaptation of these landraces to the local eco-climate conditions and a high potential utility of these germplasm in maize breeding and cultivars improvement. Compared to genetic diversity possessed in thegermplasm of South America and the USA, Chinese maize landraces show a relatively narrower genetic background, so it is of great importance in importing and integrating different maize genetic resources from other countries and regions.