Title: Investigation of adaptability and stability of promising- rice lines in regional yield trials
Author: Maryam Hosseini Chaleshtoari
Abstract: Improvement of cultivars with high yield and cooking quality similar to local rice cultivars is one of the objectives of the new cultivars releasing program. The interaction of genotype × environment, which is evaluated in several locations and years, plays an important role in determining how genotypes performance. In this experiment, eight advanced rice genotypes originated from the local Iranian varieties with three cultivars viz. Khazar, Hashemi, and Guilane as checks were examined in a randomized complete block design (RCBD) with three replications in six environments (three years and two locations). The results of the combined analysis showed that the main effect of environment for yield traits and its components is greater than the main effect of genotype and the interaction effect of genotype × environment. The results of the GGE biplot showed that the first two components (representing the main effect of genotype) and the second (representing the interaction of genotype and environment) explained, respectively 61% and 21% of the total variation. Thus, the two components together accounted for 82% of the G +GE variation for the grain yield in all environments. Since yield and stability are two essential factors in selecting the superior genotype for different environments, therefore, it should be considered together. For this purpose, genotypes were ranked based on grain yield and stability. In addition, genotypes were examined with hypothetical ideal cultivar. The results of ranking based on grain yield and stability simultaneously and comparison with the ideal genotype indicated that the best genotype is G7, followed by G3, G8, and G2. Evaluation of qualitative characteristics revealed that G8 and G2 genotypes were superior to G7 and G3. Therefore, considering the rice taste quality preferences of Iranian consumers and subsequently in the selection and sustainable cultivation of the cultivar plays the most important role, G2 and G8 genotypes, respectively, with average yield in all environments 6.99 and 7.40, gel consistency soft and medium, grain length 7.74 and 7.17, moderate amylose content, slender grain shape, and high volume expansion rate were selected as the best genotypes. Therefore, the G8 and G2 genotypes can be considered for further on-farm evaluations in farmers’ fields for being released as new rice cultivars.
Keywords: Stability and compatibility analysis, high yielding cultivars, genotype-environment interaction, GGE biplot