Overcoming Seed Dormancy in Cleome gynandra L. to Improve Germination

Abstract

Cleome gynandra L. is a traditional semi-domesticated leafy vegetable grown in East Africa. It belongs to the family Cleomaceae. Farmers save seed from each harvest for planting in the next season. C. gynandra seeds fail to germinate when planted immediately after harvest. Studies were con ducted to determine appropriate seed treatments to overcome dormancy in freshly harvested C. gynandra seeds. Seeds were subjected to various dor mancy breaking treatments including: potassium nitrate (KN03), leaching, light, gibberellic acid (GA3) and chilling. Additional studies were carried out to determine the degree of dormancy in seeds harvested from pods at different positions on the plant. Among all treatments studied, application of GA3 at a concentration of 500 ppm resulted in the highest final germina tion. Stratification for two weeks at 5 °C and germination in dark also im proved germination significantly. While leaching had no significant effect, treatment with KN03 and light reduced germination. Seeds from lower and middle positioned siliques germinated readily compared to those from up per siliques. We suggest for commercialization of C. gynandra seed that have high potential germination, treating seeds immediately after harvest with GA3 at a concentration of 500 ppm before being packaged and sold to farmers is a possibility that can be explored.