SEED DORMANCY AND ITS ALLEVIATION IN LOVEGRASS HYBRIDS

Weeping Lovegrass, Eragrostis curvula (Schrad.) Nees, was introduced t o the Americas for soil conservation. It is a useful forage only if in tensively managed. Apomictic lovegrass hybrids, developed from introdu ctions with higher forage quality, need to be evaluated in multiple en vironments to determine their potential. Studies were to be establishe d in Argentina the same year seed was produced in the USA. This could only be accomplished if seed dormancy was low. Seed of experimental st rains were harvested in 1993 and 1994 at Temple, TX. Germination and/o r emergence experiments were conducted in alternating light-dark and d ark environments. A mixture of 2-chloroethanol and sodium hypochlorite (CHL) was evaluated as a dormancy breaking treatment. The lovegrass h ybrids studied in these experiments varied widely in germination, beca use of seed dormancy. This dormancy was largely dissipated after 0.75 yr of storage in a temperature-controlled laboratory. Thus, this post- harvest dormancy is short-lived compared with that of 'A-68' lehmann l ovegrass, Eragrostis lehmanniana Nees. Absence of Light during germina tion usually inhibited germination, but in a few genotypes it promoted germination. Seed treatment with CHL compensated for absence of light . Effects of CHL on emergence did not decrease with time, but the diff erence between treated and untreated seed decreased as the post-harves t dormancy declined with seed ageing. Concerns about obtaining adequat e plants for establishment of plots in South America the same year see d was harvested were valid. Treatment of seed with CHL was a rapid, ea sy, and effective procedure for breaking seed dormancy in E. curvula a nd in E. lehmanniana and for obtaining the numbers of plants required for evaluation experiments. However, CHL is toxic and should only be u sed for seed treatment in Laboratories where human exposure to the che mical can be controlled.