Combining Abilities and Heterosis for Forage Yield among High-Yielding Accessions of the Alfalfa Core Collection

Characterization of genetic parameters in plant germplasm repository populations can facilitate their utilization in commercial breeding programs. This study investigated genetic combining abilities and heterosis for forage yield among diallel hybrids derived from nine previously selected high-yielding accessions of the USDA-ARS National Plant Germplasm System core collection of alfalfa (Medicago sativa subsp. sativa L.). These accessions originated from Turkey, South Africa, Greece, Afghanistan, Israel, Uzbekistan, Mexico, Morocco, and the USA. Forage yield response of the parents and their hybrids was determined near Las Cruces, New Mexico. General combining ability (GCA) and specific combining ability (SCA) effects were significant. The magnitudes of the GCA effects were about 5% (