Investigation of different populations of tall festuca (Festuca arundinacea) under rainfed and irrigation conditions using graphical analysis of GGE biplot

Tall festuca (Festuca arundinacea) is one of the most important crops and rangelands, with a high tolerance to different climatic conditions and its effective role in livestock feed and rangeland regeneration. In the present study, 36 populations of tall festuca from the Iranian Natural Resources Gene Bank were used that. Plant materials were evaluated in a randomized complete block design under two irrigation and rainfed conditions at Kheirabad Research Station, Zanjan, Iran, during 2005-2007. The results of the biplot method showed that the first component (as main effect of genotype or G) and second component (as genotype environment interaction effect or GE)  were 49% and 28%, respectively, and totally explained 77% of the total variation, that is showing relatively good reliability in explanation of G+GE variations. Results of the graphical method indicated that in all environments, the population G15 (Tavankash), G31 (Australia), G11 (Borujen), G25 (Occupied Palestine) and G35 (Ireland) had relatively high yield and stability. Also, according to the ideal genotype, the G35 (Ireland) and G25 (Occupied Palestine) populations were identified as the nearest populations to ideal hypothetical genotype which are the most compatible populations suggested for the environments.