Evaluation of yield stability of forage sorghum [Sorghum bicolor (L.) Moench] genotypes using AMMI analysis

Sorghum is an important forage crop used as silage, fresh forage and dry forage. To evaluate the yield stability of 16 genotypes; cultivars, lines and hybrids, of forage sorghum, experiments were conducted using randomized complete block design with three replications during 2016-17 at Karaj, Isfahan, Gorgan, and Mashhad field stations, Iran. The results of combined analysis of variance showed that the effect of location, year, genotype and their interactions were significant on forage yield. Mean comparison showed that hybrids No. 8 (Siloking) and 12 (FGCSI12) were superior to other genotypes with 130.6 and 127.5 t.ha-1 of fresh forage yiled, and 26.97 and 27.17 t.ha-1 of dry forage yield, respectively. The hybrid No. 2 (Speedfeed), No. 9 (PHFS-27), No. 5 (Juicy Sweet BMR SSH.1) and No. 13 (Sucarose- Photo- BMR) had also high fresh forage yield of 105.6, 107.8, 108.2 and 107t.ha-1, respectively. The analysis of variance by AMMI method and fitting of principal components to the interaction effects of genotype and environment showed that the two principal components were significant for fresh and dry forage yield. According to the AMMI model and AMMI stability value (ASV), genotypes No. 8 (Siloking) and 12 (FGCSI12) with the high yield and stability were identified as suitable genotypes.