Genotype × Environment Interaction and Grain and Forage Yield Stability of Promising Lines of Dual-Purpose Sorghum

To evaluate the interaction pattern of genotype × environment and grain and dry forage yield stability of 10 promising dual purpose sorghum lines, a field experiment was carried out using randomized complete block design with four replications in six field stations of Karaj, Mashhad, Birjand, Zabol, Moghan and Isfahan in 2014 and 2015 growing seasons. Combined analysis of variance showed that the main effects of year, location, and genotypes as well as their interaction effects were significant (p <0.01) on grain yield, dry forage yield and biological yield. Mean comparison showed that line No. 3 (KDFGS9) with grain yield of 7.8 tha-1 had the highest grain yield, and line No. 1 (KDFGS4) and line number 9 (KDFGS26) with 26.2 and 26.1 tha-1 had the highest dry forage yield, respectively. Line No. 1 (KDFGS4), No. 2 (KDFGS6) and No. 9 (KDFGS26) were superior to the others by producing of 34.3, 33 and 32.5 tha-1 of biological yield, respectively. Analysis of variance by AMMI model and fitting of main components to the genotype by environment interaction effect showed that two main components for grain yield, dry forage yield and biological yield were significant. The first two components explained 67.8 percent of the sum of the squares of the interaction. According to the AMMI model and ASV stability parameter, lines No. 2 (KDFGS6) and No. 3) KDFGS9( with high grain and dry forage yield stability were the most suitable lines for dual purpose with the priority of grain production. On the other hand, lines No. 9 (KDFGS26) and No. 1 (KDFGS4) can be released as dual-purpose cultivars with the priority of forage production.