Effects of Phenological Stages on Yield and Quality Traits in 22 Populations of Tall Wheatgrass Agropyron elongatum Grown in Lorestan, Iran

The objective of this research was to study the effects of phenological stages on yield and quality traits in 22 populations of tall wheatgrass Agropyron elongatum. A split plot design was conducted using a complete randomized block with two replications in Lorestan (Borujerd), Iran during 2007-2008. The genotypes were cut in five maturity stages as vegetation, stem elongation, heading date, anthesis, milky development and dough seed stage as main plots. Data were collected and analyzed for DM yield, stem number, plant height and three quality traits as; dry matter digestibility (DMD), water soluble carbohydrate (WSC) and crude protein (CP). The results showed the significant effects of phonological stages, genotypes and genotypes×phonology interaction effects for all of traits except stem number. The stem elongation and dough seed stages with average values of 2.58 and 5.08 Kg/ha had the lowest and highest yield production, respectively. In contrast, the average values of DMD and CP were high in both vegetation and stem elongation stages and they dramatically decreased in mature hay by 13% and 35% lower than those of vegetation hay, respectively. For WSC, the highest values (14.3 and 14.4%) were obtained in heading and pollination stages. Based on both yield and quality traits, it concluded that heading and pollination stages were the best stage for harvesting maximum DM yield couple with three quality traits DMD, WSC and CP yields in tall wheatgrass under conservation management. In comparison among genotypes, 301P10 (Alborz), 301M2 (Alborz) and 1599P10 (Gorgan), 1599P4 (Gorgan) 774M (Takestan) and 1755P9 (Ormia) with the range of 4.03 and 4.98 ton/ha had the higher forage production. Among them, 1599P10 (Gorgan), 774M (Takestan) and 1755P9 (Ormia) were recognized as the best genotypes for both yield and quality trait.