Recurrent Mass Selection for Improved Seed Yields in Intermediate Wheatgrass1

Abstract

The first cultivars of intermediate wheatgrass (Agropyron intermedium Host., Beauv.), released in North America had poor seed yields. At Saskatoon a breeding program of recurrent mass selection was carried out from 1955 to 1971 to develop more fertile strains. In each cycle of selection, 1,000 plants were evaluated visually for seed filling, and 50 of the most desirable plants were harvested. Seed of those with best seed yields and good seed quality was used to plant the nursery for the next cycle of selection. Open‐pollination (OP) seed was used for propagation in early cycles and controlled‐pollination (CP) seed was used in later cycles.The rate of seed yield improvement per cycle was 10.2% for OP propagation and 20.3 for the CP method. Slight concurrent improvements were made in forage yield, resistance to lodging, and seed quality. Herbage quality of selected lots was generally below that of the ‘Ree’ check cultivar but without a consistent trend.A single cycle of polycross breeding gave somewhat greater improvement than a single cycle of mass selection, but required more years to complete.Although selection was confined to a single station, the improvements obtained were noted regionally.