Determination of Selection Criteria for Yield Improvement in Rice Through Path Analysis

This study was undertaken with the objective to determine the association between grain yield and its components and identifying traits have the greatest effects on grain yield of 25 rice cultivars، in a randomized complete block design with three replications. Correlation coefficients between traits indicate that traits the number of grains per panicle، number of filled grains per panicle، ratio of grain length to width and number of productive tillers were significantly associated with grain yield. Stepwise regression method was applied to study the effect of each trait on yield and also to fit the best regression model. Results showed that the traits including number of grains per panicle، number of productive tillers and grain length explained 31، 35. 1 and 8. 1 percent of grain yield variation، respectively. Results of path analysis showed that maximum direct effects belonged to the number of reproductive tillers (0. 820) and the total number of grains per panicle (0. 714). Number of filled grains per panicle had the greatest indirect effect (0. 664) on grain yield. On the basis of results of this study suggested number of productive tillers and the number of total grains per panicle could be considered as selection criteria for grain yield improvement in rice.