Improving Germination in Windmillgrass Ecotypes
Abstract
Hooded windmillgrass (Chloris cucullata Bisch.) and shortspike windmillgrass (C. subdolichostachya Muell.) are native perennial grasses with potential for planting on highly erodible sites and on sites where introduced species are not desired. However, in both species, seeds are dormant resulting in poor germination. The objectives of this study were to evaluate effects of lemma and palea removal and caryopsis scarification on seed germination of 8 outstanding ecotypes selected in previous studies for survival and growth characteristics. Seed treatments were 1) whole seed, 2) naked caryopsis, 3) scarified naked caryopsis (30 s), 4) scarified naked caryopsis (50 s), and 5) scarified naked caryopsis (60 s). Germination conditions were 12 h dark 208C and 12 h light 308C. Seed lot viability varied from 55% to 62% for shortspike windmillgrass ecotypes and from 71% to 78% for hooded windmillgrass ecotypes. Initial germination index (MIR10) of naked caryopsis for shortspike windmillgrass ecotypes ranged from 16.3 to 21.6, compared to range from 0.2 to 0.6 to whole seed; whereas hooded windmillgrass ecotypes MIR10 ranged from 30.6 to 33.0 to naked caryopsis, compared to range from 5.8 to 8.0 to whole seed. The greatest total germination (P , 0.05) was obtained with naked caryopsis for all ecotypes and the scarification treatments did not have a positive effect on this parameter. As scarification time in- creased the total germination decreased. Lemma and palea removal improved (P , 0.05) total germination for all studied ecotypes.