BREEDING AND IMPROVEMENT OF QUALITY TRAITS IN ALFALFA (Medicago sativa ssp sativa L.)

An important objective in alfalfa breeding is the improvement of forage quality. The aim of this experiment was to determine the genetic control of the most important quality traits in whole plant leaves and stems of alfalfa genotypes. Quantitative genetic parameters were estimated for crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and acid detergent lignin (ADL) content. A 5x5 diallel design with reciprocals among parents from geographically different populations were studied. In the diallel study, effects due to general combining ability (GCA) were higher than those due to specific combining ability (SCA) for majority of the tested characters in analyses of whole plant. The F1 progeny effect was significant for almost all characters (except ADF content). The highest values of narrow sense heritability's were found for NDF (h = 0.19) and CP (h = 0.17) in whole plant, and in leaves (0.11 and 0.08), while in stems most heritable traits are ADF (h = 0.29) and ADL (h = 0.16) content. As a consequence, CP, NDF and ADF content would be more efficient selection criteria in whole plant analyses, while ADF and ADL content would be more interesting to investigate in stems, in a breeding program for improved nutritive value of alfalfa.