BIG BLUESTEM AND SWITCHGRASS ESTABLISHMENT AS INFLUENCED BY SEED PRIMING

Seed dormancy and slow seedling development often limit establishment of warm-season grass stands. Establishment of seedlings with two solid matrix seed priming (SMP) treatments [2-d moistened (17-degrees-C) and 14-d wet-chill (4-degrees-C)] was compared with untreated seed of 'Kaw' and 'Pawnee' big bluestem (Andropogon gerardii Vitman) and 'Pathfinder' and 'Cave-in-Rock' switchgrass (Panicum virgatum L.) in greehouse and field experiments. In two greenhouse studies, seedling emergence was monitored from 7 to 26 d after planting and number of adventitious roots were monitored from 2 to 5 wk after planting. Field experiments were initiated on 19 Apr. 1988, 3 June 1988, and 23 May 1989, on a Sharpsburg silty clay loam (fine montmorillonitic, mesic, Typic Argiudolls). In the greenhouse, SMP treatments increased big bluestem emergency by 18%. In the field, final seedling emergency from dry untreated big bluestem seed was equal to or higher than that of SMP-treated seed. The SMP treatments had no effect on adventitious root formation for big bluestem in either greenhouse or field experiments. In the greenhouse, the moistened and wet-chill treatments increased seedling emergency of switchgrass 35 and 150%, respectively. In the greenhouse, SMP treatments slightly increased the percentage of switchgrass plants with adventitious root development 5 wk after planting but not in the field studies. Number of adventitious roots per plant were unaffected by treatment. In the field, the SMP-treated seed produced the highest seedling emergence for switchgrass under moist planting conditions and had the potential to improve stands when seed was planted without drying. However, final seedling emergence from dry untreated seed was greater than that for SMP-treated seed under dry soil conditions.