Responce of sunflower to variuos pre-germination techniques for breaking seed dormancy

Seed dormancy is considered to be a serious constraint in sunflower seed production. viable seeds sometimes do not germinate even in the presence of favorable environmental conditions. such seeds are suspected to be dormant. the study was conducted under controlled/laboratory conditions during spring 2010 at national agricultural research centre,islamabad. the objective of the study was to evaluate some techniques to convert a seed from dormant to non-dormant germinable state. dormant seeds of 21 sunflower hybrids were treated with three hot water treatments (100°/80°c) and four chemicals potassium nitrate,0.2%,thiourea,0.5%,ethanol,25%,acetone,25% for breaking seed dormancy .the untreated seed was taken as control. soaking seeds in hot water (80°c) for 15 minutes followed by one day dry and seed treatment with acetone were found to be the most effective and successful techniques in converting the seed from dormant to non-dormant state. © 2015,pakistan botanical society. all rights reserved.