Abstract:

This research explored the effects of geographic factors on phenotypic traits and seed yield in Haiyan County， Haibei Tibetan Autonomous Prefecture， Qinghai Province， using 20 lines of Elymus nutans from different sources in the Tibetan Plateau region. A range of geographic locations and altitudinal gradients were selected for the collection of E.nutans， with the aim of providing a theoretical basis for the screening of E.nutans resources and breeding varieties on the Tibetan Plateau. The results were as follows： The coefficients of variation of the phenotypic traits ranged from 6.560% to 33.164%， and the diversity indices of each trait were above 1.4， indicating that the germplasm resources have rich genetic diversity. A structural equation model showed that flag leaf length， inflorescence length， rachis length of the first internode and seed weight per inflorescence were the most important factors affecting the seed yield of E. nutans. Correlation analysis showed that flag leaf length， inflorescence length， rachis length of the first internode， seed weight per inflorescence and seed yield were more affected by geographic factors. Values for all of the above phenotypic traits decreased with increasing altitude and increased with increasing longitude and latitude. Through cluster analysis， it was concluded that plants found in the altitude range of 2600-3350 m， at longitudes near 101° E and in the latitude range between 35°-37° N have excellent values for leaf and spike traits and are rich in varietal type. Therefore this area can be used for the selection and breeding of the germplasm resources of the excellent E. nutans.

Key words: Elymus nutans, phenotype trait, seed production traits, geographical factors