GROWTH-REGULATOR AND SEED STORAGE EFFECTS ON SWITCHGRASS GERMINATION

Switchgrass (Panicum virgatum L.) is a warm season perennial grass tha t shows potential as a forage in the southeastern USA. Problems with s witchgrass establishment from seed are often due to inherent seed dorm ancy from seeds harvested in fall and seeded the following spring. The objectives of this study were to determine (i) the effects of wet pre chill (PC) treatment (5-degrees-C for 14 d) and scarification (8 M H2S O4 for 5 min) on germination of five switchgrass cultivars and (ii) th e effect of plant growth regulators (ethylene, gibberellin, and kineti n), CO2, PC, and influence of storage temperature and duration on germ ination of four selected lots of Blackwell (BW) and Cave-in-Rock (CIR) seeds. Storage treatments were initiated 1 February using seeds harve sted the previous fall. Early germination percentage (7 d) was increas ed between 22 and 73 by PC, while final germination percentage (28 d) was increased between 2 and 40. Germination of BW 6086 was increased f rom 60 to 63% by ethylene, and from 59 to 65% by gibberellin (alpha = 0.05). Seeds stored at -8-degrees-C showed little change in early or f inal germination with time of storage (90 d to 4 yr). Dormancy of BW 1 198, BW 6086, and CIR 6012 was largely broken after 90 d of storage at 23-degrees-C. Germination of seeds stored at 23-degrees-C generally s tarted to decline after 180 d to 2 yr. Postharvest storage of seeds at 23-degrees-C from january to April (90 d) should ensure adequate germ ination at time of seeding.