Abstract:

【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 carried 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 the germplasm 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.

Key words: maize (Zea mays L.), landrace, core collection, principal component analysis, racial classification