Stability evaluation of advanced soybean lines (Glycine max L.) in drought conditions using GGE-Biplot analysis and Ammi

Soja (Glycine max L.) is the most important oil crop in the world. Soybean yield and its geographical distribution in the country can be severely limited by abiotic practices such as drought. There is a constant need to improve soybean cultivars with stable yields in different environments. In this study, the stability and adaptability of advanced soybean lines under water stress conditions have been investigated.

In this study, 14 top soybean lines that were superior in preliminary soybean yield evaluation experiments in different regions along with two cultivars, Saba and Kowsar, in two separate experiments. They were evaluated in a randomized complete block design with three replications in the two years of 2015-2016 in Karaj. Both experiments were similarly irrigated until seedling establishment and the emergence of the V4-V5 stage, which coincided with the complete development of the fourth to fifth of three-leaf. After that, the first experiment was irrigated weekly and the second one every other week (50-55 and 100-120 mm evaporation from Class A evaporation pan, respectively). At the end of two years, the stability and adaptability of the lines were evaluated by GGE biplot, AMMI, and the rank of the mean yield.

The results showed that the effects of genotype, environment and genotype × environment explained 20, 68, and 12% of the total squares, respectively. Also, the first two main components were significant and each of them accounted for 67 and 24% of the total squares, respectively. The results of this study showed that the highest seed yield in non-stress conditions was observed in G1, G3 and G2 lines, respectively. Also in drought stress conditions, the highest seed yield was obtained from G3 and G2 lines. The G3 line was known as a drought tolerant genotype with higher than total average yield in both non-stress and stress conditions.

According to the mean rank and standard deviation of seed yield rank of lines biplot diagram, G3, G1, G2, G7 had the least interaction with the environment and were identified as stable lines. in the first two main components biplot diagram, and the AMMI stability value (ASV) with the lines seed yield biplot diagram, G2, G6, G3, G1, G7 were recognized as more stable lines. Based on the GGE polygon diagram, lines G1, G6, G2, G7, G4, and G5 were also selected. Also, G3, and G8 lines showed good private adaptability with Karaj in stress-non stress conditions. The results showed that line G3, G1, G2 with higher seed yield than the total mean and control cultivars can be introduced as a suitable line for cultivation in low water areas.and they can also be used in future breeding programs.