PROTEIN DEGRADABILITY IN A DIVERSE ARRAY OF ALFALFA GERMPLASM SOURCES

The shortcomings of alfalfa (Medicago sativa L.) as a high quality for age include extensive ruminal degradation of the forage protein, somet imes with concomitant loss through ammonia formation. This study was c onducted to determine if significant differences exist in the degradab ility of forage protein among nine basic alfalfa germplasm sources, an d germplasms with epidermal glandular hairs from M. glandulosa David o r M. glutinosa M.B. Inter- and intrapopulation variation of protein de gradability was assessed by an in vitro test based on the extent of de gradation by the proteolytic enzyme ficin. The rates of degradation we re significantly different among the alfalfa lines, but the proportion s of protein lost were equivalent after a 2-h digestion. Intrapopulati on variation, assessed with 10 plants from each of 10 sources, was qui te high, suggesting that adapted cultivars with decreased protein degr adability could be developed through conventional breeding methods, if selections were carried out on an individual plant basis.