Analysis of Stability and Adoptability of Forage Yield among Silage Corn Hybrids

The objectives of this study were to analyze genotype by environment (GE) interactions effects on the forage yield of 8 corn hybrids by computing AMMI analysis and evaluating genotype (G), environments (E) and GE interactions using stability parameter i.e., AMMI stability value(ASV) and Wrick,s ecovalance (W2i). Experiments were conducted at five regions (karaj, Neysahbur, Gorgan, Brojerd and Isfahan Research Station), during 2005-2006 crop season. The result’s of AMMI analysis for forage yield indicated that the Genotype (G) main effects, environment (E) and GE interactions as well as three first interaction principal components (IPCA1-3) were significant. AMMI biplot was able to distinguish stable genotypes and environments with high discrimination ability from low one,s. AMMI ANNOVA selected different hybrids for each regions: No. 5, 8 and 1 for Karaj , 5, 2 and 8 for Neyshabur, 1 and 5 for Gorgan, 8, 5and 1 for Brojerd and finally hybrids No. 5, 8 and 2 for Isfahan. According to the AMMI analysis and the parameters investigated, genotype 5, with forage yield higher than grand mean, was the most stable hybrid and with high adaptation to the environment was studied, meanwhile Hybrids No. 7 and 8 had the greatest influence on the interaction but were the unstable genotypes tested in all years and areas.