Nutritive values of smooth bromegrass, meadow bromegrass, and meadow X smooth bromegrass hybrids for different plant parts and growth stages

Three hybrid populations between meadow bromegrass (Bromus riparius Rehm.) and smooth bromegrass (Bromus inermis Leyss) have been developed through hy bridization and recurrent selection. The objective of this study was to det ermine the concentration of acid detergent fiber (ADF), neutral detergent f iber (NDF), and crude protein (CP) of leaf blades, stems, and whole-plant h erbage of three hybrid bromegrass populations (S-9197, S-9073 and S-9183) a nd the two parental species at vegetative, heading, and anthesis stages of development. Generally, the highest leaf blade NDF, ADF, and lowest CP conc entrations were observed in meadow bromegrass, regardless of the growth sta ge. For the stem fraction, hybrid S-9183 had the lowest ADF (240 g kg(-1)) and NDF (532 g kg(-1)) at the vegetative stage. At anthesis, in 1997, stem NDF concentrations of meadow bromegrass, S-9197, and S-9073 were similar, b ut lower than S-9183 and smooth bromegrass. At later stages of development, meadow bromegrass had higher stem CP concentrations (94-114 g kg(-1)) than other entries (62-110 g kg(-1)). For whole-plant samples, NDF (359-490 g k g(-1)) and ADF (178-214 g kg(-1)) concentrations of the three hybrid popula tions were consistently lower than the parental species at the vegetative s tage of growth. The hybrid populations, particularly S-9183, were lower in NDF and ADF at early stages of maturity, suggesting that they have potentia l as high quality forage species for grazing and hay prior to or at heading .