Genotype × Environment Interaction and Grain Yield Stability Analysis of Rice Genotypes (Oryza sativa L.)

Considering the increase in per capita consumption of rice in the country and the need to increase rice production per unit area, it is very important to introduce new high-quality varieties with high yield and stable grain yield. The grain yield depends on the genotype and its response to environmental conditions. To increase the quantity and quality of rice, this research was conducted to evaluate the interaction between genotype × environment and to determine the stability of the grain yield of rice genotypes.

In this experiment, 8 quality rice lines were carried out including Kadus, Ali Kazemi, and Champa local cultivars in the form of Randomized Complet Block Design with three replications in Cheram and Basht regions during 2017 and 2018. In each year, the performance of tested genotypes was tested separately using simple variance analysis and using Duncan's method, and at the end of the second year, combined analysis was performed to determine the compatibility. To analyze the stability and compatibility of lines, Shukla's stability variance, Francis and Kanenberg's coefficient of environmental changes, Wrickes ecovalence, deviation from Eberhart and Russell's regression line, Finley and Wilkinson's regression coefficient and Pintos' coefficient of identification were used.

The results showed a great diversity between the investigated genotypes in terms of grain yield and other agricultural traits. Composite variance analysis showed that there is a significant difference between years at the 5% probability level. The stability analysis of the genotypes by calculating the stability parameter shows that the highest stability was related to the local Champa variety and lines 7, 8, 5, and 6. Based on the calculated Eberhart & Russell Method, genotypes 7, 6, and 8 and the local Champa variety were favorable in both test environments. In terms of Wrickes ecovalence, and stability parameter, the local Champa cultivar and genotypes 6 and 5 were the best. Based on the results of the analysis and comparison of the average of the treatments, the superiority of the grain yield was related to lines 7 and 5 with an average yield of 9.60 and 8.85 tons per hectare. The mentioned lines were recognized as superior genotypes due to their average yield, conversion efficiency, high percentage of whole rice, and average amylose content.

Based on the results obtained from the stability methods of lines number 7 and 5, respectively, with an average yield of 9.60 and 8.85 tons per hectare and having stability variance, environmental change coefficient, and intra-location variance less than one, as well as the coefficient of the regression line equal to one they are recommended as stable genotypes for both regions and other similar regions.