Effect of mass selection for seed density in populations derived from Avena abyssinica x A. sativa amphidecaploids

Summary Seed of two heterogeneous amphidecaploid Avena populations (NY79143 and NY79148) were separated into three groups based on seed density using a commercial gravity table. Bulk populations were evaluated in a field trial to test the effect of selection for seed density on agronomic characteristics, while chromosome behavior was studied on similarly selected individual plants grown in a coldframe. Selection for seed density was associated with improved agronomic characteristics for individual plants grown in coldframes but the treatment effect was not significant in the field trial. Population and treatment effects were significant for chromosome number. Mean chromosome numbers were higher in NY79148 than in NY79143, and increased with selection for seed density. Populations did not differ for mean somatic instability but did show interactive population^*treatment effects. Several generations of selection for seed density is suggested.