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) an d 14-d wet-chill (4-degrees-C)] was compared with untreated seed of 'K aw' and 'Pawnee' big bluestem (Andropogon gerardii Vitman) and 'Pathfi nder' and 'Cave-in-Rock' switchgrass (Panicum virgatum L.) in greehous e and field experiments. In two greenhouse studies, seedling emergence was monitored from 7 to 26 d after planting and number of adventitiou s roots were monitored from 2 to 5 wk after planting. Field experiment s were initiated on 19 Apr. 1988, 3 June 1988, and 23 May 1989, on a S harpsburg silty clay loam (fine montmorillonitic, mesic, Typic Argiudo lls). In the greenhouse, SMP treatments increased big bluestem emergen cy by 18%. In the field, final seedling emergency from dry untreated b ig bluestem seed was equal to or higher than that of SMP-treated seed. The SMP treatments had no effect on adventitious root formation for b ig bluestem in either greenhouse or field experiments. In the greenhou se, the moistened and wet-chill treatments increased seedling emergenc y of switchgrass 35 and 150%, respectively. In the greenhouse, SMP tre atments slightly increased the percentage of switchgrass plants with a dventitious root development 5 wk after planting but not in the field studies. Number of adventitious roots per plant were unaffected by tre atment. In the field, the SMP-treated seed produced the highest seedli ng emergence for switchgrass under moist planting conditions and had t he potential to improve stands when seed was planted without drying. H owever, final seedling emergence from dry untreated seed was greater t han that for SMP-treated seed under dry soil conditions.