Effect of moisture content and storage temperature on germination and seedling vigor index in Clitoria ternatea L.

Abstract

Clitoria ternatea L. commonly known as Aparajita is a valuable medicinal plant used in the traditional Indian systems of medicine. The major problem in propagation of C. ternatea through seed is poor germination and seedling vigor. In the present study, the effect of moisture content and storage temperature on germinability and seedling vigor during long term storage of Clitoria ternatea seed was investigated. The seed moisture level was decreased to 5% and increased to 10–12% and stored at-20, 20 and 30oC for one year. Both the control and treated seeds showed a gradual increase in germination percentage after 6 months duration indicating physiological dormancy. The increase in moisture level to 10–12% during storage at-20 and 20oC resulted in higher germination percentage and vigor index from 3 months of storage onwards till one year. The storage of seeds with higher moisture level at 30oC showed relatively less mean germination time and higher germinability up to 6 months and thereafter it declined significantly. Among the different moisture levels and storage conditions investigated, seeds desiccated to 10% moisture level and stored at 20oC showed relatively higher germinability, less mean germination time and high vigor index. Results indicate that in Clitoria ternatea, since the seeds are moisture sensitive, altering the level of seed moisture is an effective method to break dormancy and storage at low temperature (−20 and 20oC) is crucial for maintaining the viability of these seeds.