Assessment of Yield and Agronomic Characteristics of Promising Lines of Rice

Determination of morphological characteristics of different promising lines of rice and the effects they have on yield can be considered a good tool for identification of preferable lines with ideal agronomical traits.

In order to evaluate the most important characteristics of cultivars affecting yield in 2017, a field experiment was conducted in a research farm of Sari University of Agricultural Sciences and Natural Resources, in a randomized complete block design with three replications, in 5 square meters plots with 25×25 space between them. Morphological characteristics include plant height, panicle length and number measured before harvest in the farm, as well as other characteristics after harvest in laboratory. At the end of growth season, panicles were harvested and collected in separate bags and were selected randomly for measurement of their morphological characteristics. Mean comparisons were calculated with Duncan method in 5% level of possibility. Also, variance analysis was calculated for all the traits. Cluster analysis was calculated with ward method. The genotypes were 30 promising lines of rice. In this study, 10 traits including plant height, panicle length, panicle number, total number of grains, number of filled grains, grain length, grain diameter, grain length to width ratio, 1000 grain weight and yield were evaluated.

Correlation analysis results showed that there was a positive and significant correlation between yield and number of panicles, number of filled grains and 1000 grain weight, but the length of the grain had a negative significant correlation with yield.The results of path analysis showed that the number of filled grains had the highest direct effect (0.67), and, after that, the number of panicles (0.59) and grain width (0.47) had the highest effect on yield.Therefore, based on the results obtained from this study, number of panicles and number of filled grains as selection index on rice yield improvement were identified.The results of cluster analysis of the studied lines were also classified into four groups. The genotypes in the second and the third, in addition to the higher yields, had the lower height, number of tillers and more grain number.The average deviation of clusters from total mean was calculated for these lines and the existence of this deviation can demonstrate diversity. The genotypes in the second group add up to 57% of all the genotypes, which is above the total mean in traits including panicle number, grain length, grain diameter, 1000 grain weight and yield.

According to the results of this study, the highest lines in terms of yield and other agronomical characteristics were 8, 13, 14, 15 and 28. Also, traits including number of panicles and filled grain number can be considered selecting factors for improvement of rice yield.