Path Analyses of Yield and Yield‐Related Traits of Fifteen Diverse Rice Genotypes

Literature on the path analyses of grain yield and at least 14 yield related traits in a path diagram that is organized with at least second order variables has been lacking. The objectives of this study were to obtain and interpret information on the nature of interrelationships between first‐, second‐, and third‐order yield‐related traits and rice (Oryza sativa L.) grain yield. Fifteen rice genotypes were used in this study to represent the combinations of low and high levels of four traits that were identified as important yield determinants — maximum number of tillers, grain size, panicle node number, and panicle size. ‘Lemont’ and ‘Teqing’ were two of these genotypes. The remaining genotypes were F9 lines from a Lemont × Teqing cross. Field experiments were conducted during the 1994 and 1995 cropping seasons at the Texas A&M University Agricultural Research and Extension Center near Beaumont, TX. The 1994 path coefficient (p) of panicle weight on grain yield (p = 0.72; r2 = 0.93) was used to predict the 1995 grain yield (r2 = 0.90). Based on a path analysis of the combined 1994 and 1995 data, the following traits had positive path coefficients on grain yield: panicle weight (p = 0.84), number of filled grains per panicle (p = 0.67), panicle density (p = 0.52), maximum filler density (p = 0.34), number of spikelets per panicle (p = 0.34), and 100‐grain weight (p = 0.23). The panicle node number has a negative path coefficient on grain yield (p = −0.23). These results may be useful to rice breeders for the indirect selection of grain yield during the early segregating generations when yield tests are not yet being conducted.