Correlation analysis of seed yield with agronomic traits in Elymus nutans ‘Baqing’

Elymus nutans is the first domesticated wild forage grass in Tibet. We selected three seed yield indices and seven agronomic traits in an effort to identify correlations between seed yield and agronomic traits of E. nutans ‘Baqing’. We sought to identify correlations between seed yield and agronomic traits of E. nutans ‘Baqing’ by principal component analysis, typical correlation analysis, and a stepwise regression method. Correlation analysis revealed that the number of spikes per plant and yield per plant both correlated positively with plant height, number of tillers, and mean flag leaf length (P < 0.01) with a high degree of significance. Typical correlation analysis revealed that the number of tillers and seed length structure coefficients increased with increases in the combined agronomic trait index variables V1 and V2, indicating that the number of tillers and plant height are the main factors determining seed yield from Plantago lanceolata pendants. Stepwise regression analysis gave highly significant (P < 0.01) coefficients correlating single plant yield with number of single spikes and average number of grains per spike. The average number of grains per spike was significantly different from the partial correlations between number of single spikes, seed length, average number of nodules, plant height, and average flag leaf length (P < 0.05). The partial correlation of the number of single spikes with seed length, awn length, and average number of nodules per spike was found to be significantly different (P < 0.05). Therefore, the number of panicles per plant and the yield per plant could be increased by increasing the length of flag leaf, and the seed yield of Elymus nutans could be increased.