Effects of temperature, pre-chilling and light on seed germination of Withania somnifera; a high value medicinal plant

Withania somnifera is under intensive utilization because of its wide ranging medicinal potential. Self-propagation of this species is by seed. In an effort to improve and promote the cultivation of this over-exploited medicinal herb, the effects of temperature and light on the germination of its seeds were investigated. Germination was found to be temperature and light-dependent. Although seed viability was 78.8% as determined by tetrazolium staining, maximum germination was only 46%. Pre-chilling treatments reduced the germination of the seeds, while exposure to constant temperatures of 25 °C, 35 °C and 45 °C in the dark completely inhibited germination. A regime of alternating temperatures partially suppressed the light requirement and improved germination of the seeds.