Multi-environment Yield Trials of Grass Pea (Lathyrus sativus L.) in Iran Using AMMI and SREG GGE

Grass pea (Lathyrus sativus L.) is a crop used for both animal and human consumption. Recently, ICARDA has developed new grass pea lines with the objectives of improving its yield potential and adaptability. The objective of this study was to investigate grain and forage yields stability of several ICARDA released grass pea lines by using additive main effects and multiplicative interactions (AMMI) and site regression genotype plus genotype-by-environment interaction (SREG GGE) model. Fourteen grass pea advanced lines were evaluated at three research stations located in semi-warm regions in Iran, during 2005-08 crop seasons. The combined ANOVA showed that forage and grain yields were significantly affected by environment (E), genotype (G) and interactions of G×E. The partitioning of the sum of squares indicated that E accounted for 85% and 91% of the total (G+E+GEI) variation for forage and grain yields, respectively; whereas, G and GEI accounted for 4 and 11% for forage yield and 2 and 7% for grain yields, respectively. Using AMMI and GGE biplots, the lines identified as stable and high grain yielding were Sel.474, Sel.669, and Sel.686, while for forage yield the lines were Sel.474, Sel.678 and Sel.669. Kermanshah and Gachsaran were selected as favorable test environments for grass pea grain and forage yield ME trials, respectively.