The Differences Of Nutrients Variation During Growth Among And In Lines Of Early And Late Maturity In Italian Ryegrass

Italian ryegrass (Lolium multiflorum Lam.) is one of the most important over-winter forages in middle and low region of Yangtze River of China and suitable for feeding many kinds of herbivores. The herbage yield of Italian ryegrass increased greatly with the advancement of cultivation techniques and increasing fertilizer application, but the digestibility of its dry matter was not improved. It is necessary for forage breeding to resolve the contradiction between yield and digestibility.In order to clarify the rules of nutrient variation and the differences between early and late maturity lines of Italian ryegrass during growth, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), water soluble carbohydrates (WSC) and in vitro dry matter digestibility (IVDMD) in leaf blade, leaf sheath and culm were determined in a field experiment. Growth traits and the correlations between IVDMD and CP, NDF, ADF content were analyzed. The results showed as follows.At initial heading stage, IVDMD reached a peak (67.7%) and then decreased rapidly after heading stage in early maturity line from booting stage to anthesis stage. Compared with early maturity line, IVDMD of late maturity line was retained on the higher level, which appeared the peak (69.3%) at booting stage, then decreased slowly with growth progressing from elongating stage to anthesis stage.IVDMD of the plant components was the highest in leaf blade, and followed by culm and leaf sheath.The positively significant correlation (p<0.05 ) existed between IVDMD in culm and that of whole plant. IVDMD of whole plant was greatly determined by that of culm. The determination coefficients (r~2) of early and late maturity lines were estimated to be...