Selection for Fiber and Protein Concentration in a Diverse Alfalfa Population¹

Abstract

A diverse alfalfa population derived from crosses within and among the species Medicago sativa L., M. falcata L., and M. caerulea Less. was evaluated for variation in acid‐detergent fiber (ADF) and crude protein (CP) concentration. A sequential selection scheme based on first and second harvest ADF, CP, and yield was developed to identify vigorous plants with differing levels of the nutritional characteristics. An analysis of two five‐parent diallel sets indicated that variation in ADF and CP concentration among crosses was accounted for primarily by general combining ability. Four experimental synthetics were grown in small plots and evaluated for yield and nutritional quality. The low fiber and high protein synthetics averaged 5.7% (1.9 units) lower in ADF, and 7.2% (1.5 units) higher in CP than the cultivars Vernal and Honeoye