Seed dormancy and aging in atra paspalum

Seed dormancy and aging affect maintenance of germination in storage and ultimately seedling establishment. The effects that year of harvest, heat vs. air drying seed at harvest, storage environment, and aging had on germination of 'Suerte' atra paspalum (Paspalum atratum Swallen) were studied. Across 5 yr, average germination of fresh seed at harvest was 0% during 0 to 7 d and 5% during 8 to 14 d of a 28-d germination period. Total germination depended on year of harvest and ranged from 9 to 46%, Oven drying (40 degrees C for 24 h) at harvest increased germination in 2 of 5 yr, Storing seed for 6 mo in a building with no environmental control (ambient condition) increased germination to 69% (3-yr average) and shifted most of the germination to the first 7 d, but germination was nil after 1 Jr, Germination averaged 55% at 28 d after harvest for seed stored at 3 degrees C and changed little for up to 4 yr. Oven drying seed at harvest delayed the break in dormancy approximate to 1 mo compared with air drying seed, Chilling air-dried, ambient stored seed at 3 degrees C for 48 h before testing reduced germination at 84 d after harvest (compared with 28 d and 6 mo). Neither chilling oven-dried seed nor heat (40 degrees C for 24 h before testing) treatment of oven- and air-dried seed affected germination. Removal of the lemma and palea at harvest resulted in 96% germination compared with 26% for intact seed. Treatment of freshly harvested seed with H2SO4 for 6 min and accelerated aging (48 h at 41 degrees C, 100% relative humidity) increased germination from 29 to 68% and 30 to 48%, respectively, Dormancy in atra paspalum is short-lived and should be of minor agronomic importance with fall seed harvest and spring sowing. Consideration must be given to seed storage conditions to assure viability beyond 1 yr.