Role of testa, cotyledons and embryonic axis in seed dormancy of groundnut(Arachis hypogaea L.)

Experiments were carried out during winter-summer (January-June) season to understand the role of seed testa, cotyledons and embryonic axis in imparti ng dormancy of some groundnut cultivars belonging to different habit groups . Crop was harvested at four maturity stages; 90, 100, 110 and 121 days aft er emergence (DAE). After drying the pods in shade for 2 days, the germinat ion of seeds with (GST) and without (GSW) tests in rolled germination towel s and seeds, and embryonic axes (GEM) in culture media from individual plan ts of a cultivar was studied. Seed testa played an important role in impart ing dormancy followed by the cotyledons, and embryonic axis. However, the n ature of dormancy of embryonic axis appeared to be different from that of t he testa and cotyledons. Results suggested that the dormancy in groundnut i s regulated mainly by testa (a maternal tissue) in the Spanish type, but by cotyledons, and embryonic axis (both zygotic tissue) as well as testa in V irginia types. Thus the genetic control of seed dormancy in groundnut appea rs to be quantitative in nature.