Explanation of the relationships between seed yield and some morphological traits in smooth bromegrass (Bromus inermis Leyss.) by path analysis

摘要

Path analysis was performed on plant characters in a sward of smooth bromegrass to determine the seed yield, the direct and indirect effects of the following seed yield components: stem yield/m(2), total stem number/m(2), fertile stem number/m(2), sterile stem number/m(2), percentage of fertile stem, seeds/m(2), seeds/panicle, seed weight/panicle, 1000-seed weight, and plant height under field conditions. Seed yield was significantly correlated with all components except 1000-seed weight, total stem number/m(2), and seed weight/panicle. Stem yield/m(2), percentage of fertile stem, sterile stem number/m(2) and seeds/m(2) had substantial direct effects, in that order, on enhancement of seed yield. The significant positive correlation coefficients of fertile stem number/m(2) and plant height with seed yield resulted from positive indirect effects of stem yield/m(2) and percentage of fertile stem. Conversely, the significant negative correlation between sterile stem number/m(2) and seed yield resulted from negative indirect effects of the same two components. Stepwise multiple regression analysis showed that 54.9% of total variation in seed yield could be explained by the variation in stem yield/m(2) and by fertile stem number/m(2) (51.4 and 3.5%, respectively). Results suggest that stem yield/m(2) and fertile stem number/m(2) are primary selection criteria for improving seed yield in the sward of smooth bromegrass