Breeding system studies in Withania somnifera-an important commercial medicinal plant

Abstract

Withania somnifera (Solanaceae), is an important medicinal plant species that has therapeutic applications in traditional and modern system of medicines. The plant is valued for its roots due to presence of withanolides and shows extensive phenotypic and chemical variability. The utilization of this variability through conventional breeding requires a clear understanding of its reproductive biology and breeding system. In present study reproductive biology in Withania somnifera has been studied to understand its breeding behaviour. The results revealed that species showed remarkable interpopulation variability especially with regard to its filament, pedicel and style length that has bearing on its mating ability. Increase in filament length affects self pollination although its flowers are amenable for cross pollination initially. The flower is protogynous which is characterised by stigma becoming receptive at bud stage with anthers maturing at full blooming stage. Protogynous flowers coupled with lower position of anthers enable it for cross pollination initially. In case of incomplete xenogamy, autogamy is enabled due to increase in filament length bringing anthers at par with stigma level. The species practices mixed mating with 66% self and 34% cross pollination and this mechanism will be advantageous towards production of recombinant as well as autogamous seeds in W. somnifera. Further, different accessions of this species showed variation w.r.t. bud initiation stage, anthesis, maximum flowering stage, fruit initiation, fruit ripening and crop withering stage etc. However, the chromosomal study revealed a diploid number of 2n=48 in all the studied accessions.