To breed high yield new cultivars,half-sib seeds of 110 high yield alfalfas were selected as tested materials.General combining ability(GCA) of 1st harvest,2nd harvest,3rd harvest,4th harvest and annual total yield were measured.Cluster analysis was conducted based on GCA.Results show that 22 individual plants with high general combining ability and 48 plants with moderate general combining ability were intercrossed to complete the first recurrent selection.Low general combining ability plants(40 individual...