DRY-MATTER CONCENTRATION AS AN INDEX OF IN-VITRO DRY-MATTER DISAPPEARANCE IN BERMUDAGRASS

Simple and cost-effective procedures for predicting forage quality are needed. The objective of this study was to determine if dry matter concentration (DMC) could be used as an index of in vitro dry matter disappearance (IVDMD) in bermudagrass (Cynodon spp.). Data were from two bermudagrass trials at Tifton, GA. The 1983 and 1985 trials contained 32 and 28 entries replicated five times. Plots were harvested four times a year for 3 yr, except in 1987 when only three harvests were taken. A negative correlation was observed between DMC and IVDMD. Coefficients of determination (r2) from the regression of entry mean IVDMD on DMC from individual harvests ranged from 0.01 to 0.82. Entry DMC means averaged across harvests within years provided consistent index or IVDMD (r2 = 0.20, 0.65, 0.49, 0.57, 0.60, and 0.59). Regression coefficients differed among groups of bermudagrass entries having different genetic backgrounds. When screening bermudagrass entries for forage IVDMD, almost-equal-to 50% of the entries could be eliminated based on forage DMC if the entries are replicated over space and time.