Recurrent selection for increased seed germination in sand bluestem (Andropogon hallii)

Under field conditions, water is often inadequate for satisfactory seedling establishment (germination and emergence). This research was designed to improve the germination of sand bluestem (Andropogon hallii Hack.) populations 'AB-medium Syn-0' and 'CD-tall Syn-0' at low water potentials. Two cycles of recurrent selection were used to develop populations 'AB-medium Syn-1', 'AB-medium Syn-2', 'CD-tall Syn-1' and 'CD-tall Syn-2'. Cycle 1 consisted of germinating 3500 open-pollinated seeds of each Syn-0 population in a) 0.8 MPa D-mannitol solution for seven days. All germinated seeds (approximately 250 of each population) were selected to create the Syn-1 populations. Cycle 2 selection was similar to Cycle 1, except that Syn-1 populations were used to create Syn-2 populations. To test the effects of selection, four 50-spikelet samples of the six populations were germinated at) -0.8 MPa for seven days. Germination of Syn-1 seeds was 6.7% higher than that of Syn-0 seeds, and Syn-2 seeds were 10.2% higher than that of Syn-1 seeds. Thus, it was possible to select for increased seed germination of sand bluestem Syn-0 populations at the water potential used herein.