Performance and stability analysis of forage sorghum [Sorghum bicolor (L.) Moench] genotypes targeted to arid and semi-arid environments

Considering the limited water resources and the increasing need for fodder in arid and semi-arid regions of Iran, it is necessary to introduce new sorghum cultivars with high performance and stability. This study aimed to evaluate the yield stability of forage sorghum genotypes via AMMI and GGE biplot analysis to identify the high-yielding and most adapted genotype for release in Iran's arid and semi-arid regions. Nine promising forage sorghum lines (KFS2, KFS9, KFS10, KFS11, KFS12, KFS15, KFS16, KFS17, and KFS18), along with one commercial cultivar (Pegah), were studied at seven regions of Iran (Karaj, Gorgan, Borujerd, Sanandaj, Shiraz, Yazd, and Zabol) during the 2018 and 2019 growing seasons. The results of AMMI analysis showed that line KFS2 had the lowest AMMI stability value (ASV) and was identified as a stable genotype. The AMMI1 and AMMI2 biplots indicated that KFS2, KFS9, and KFS17 had the least interaction with the environment. The GGE biplot analysis showed that line KFS18 had the highest dry matter yield (DMY) in most environments. According to the average-environment coordination (AEC) biplot, line KFS18 followed by KFS17 were identified as the most desirable genotypes. Furthermore, among the studied environments, Gorgan and Karaj regions were the most discriminating environment for the genotypes evaluated as well as the ideal environments for sorghum cultivation. Overall, line KFS18 with the maximum DMY (32.05 Mg ha−1) and general adaptability across various environments can be introduced as the superior genotype for cultivation in Iran's arid and semi-arid regions.