Abstract:

The study aims to screen high-quality forage triticale germplasm resources in alpine pastoral areas, and to provide a theoretical basis for the breeding and promotion of high-yield and high-efficiency forage triticale varieties in this area. In this study, five forage triticale varieties were used as test materials, and their grain traits including ear length and ear weight, as well as photosynthetic parameters such as chlorophyll content and net photosynthetic rate were systematically determined. Single factor analysis of variance was used to compare the differences of indexes among different cultivars, Pearson correlation analysis was adopted to explore the correlation between various indexes, and principal component analysis(PCA) was combined for dimensionality reduction and extraction of key comprehensive indexes. Finally, TOPSIS ideal solution ranking method was used to comprehensively evaluate the tested triticale varieties. The results showed that there were significant differences in grain traits and photosynthetic characteristic indexes among all tested triticale cultivars (P<0.05). There was a close synergistic relationship between grain traits and photosynthetic performance. Specifically, ear length was significantly positively correlated with ear weight, grain number per ear, ear weight per unit area, grain weight per unit area and chlorophyll content; grain weight per ear was significantly positively correlated with ear weight per unit area and grain weight per unit area (P<0.05); thousand-grain weight was significantly negatively correlated with panicle length and grain number per panicle (P<0.05), and extremely significantly positively correlated with stomatal conductance (P<0.01). Two core components were extracted by PCA, and ear length and thousand-grain weight were identified as the core indexes determining the comprehensive performance of the tested cultivars. The comprehensive ranking of the tested cultivars by TOPSIS was as follows: ‘Qingsimai 8’ > ‘Qingsimai 7’ > ‘Qingsimai 1’ > ‘Qingsimai 2’ > ‘Qingsimai 3’. In conclusion, ‘Qingsimai 8’ presented outstanding performance in both grain traits and photosynthetic efficiency, and is a preferred cultivar with great popularization and application potential in alpine pastoral areas. This study can provide a theoretical reference for the breeding and promotion of forage triticale cultivars.

Key words: triticale, grain traits, photosynthetic characteristics, correlation analysis, TOPSIS comprehensive evaluation