Studies on the effect of biofertilizers on growth, yield and alkaloid content of Ashwagandha roots ( Withania somnifera Dunal.)

Abstract

Ashwagandha (Withania somnifera Dunal.) is one of the important medicinal plants attaining economic importance in recent days. The experiment was carried out at Department of Horticulture, Faculty of Agriculture, Annamalai University, Annamalai nagar.The treatments were conducted with the seedling dip of biofertilizers viz., Azospirillum at the rate of 500 g per hectare, phosphobacteria at the rate of 500 g per hectare and combination of Azospirillum + phosphobacteria at the rate of 1 kg per hectare. The study revealed that maximum number of 5.69 roots per plant and root length of 38.16 cm were observed in plants treated with Azospirillum + phosphobacteria. Significantly higher root diameter of 1.14 cm and root yield of 6.03 q ha-1 was recorded in the application of Azospirillum + phosphobacteria. The maximum total alkaloid content and alkaloid yield of 1.379 per cent and 8.32 kg ha-1 respectively were registered when the plants treated with Azospirillum + phosphobacteria. Hence, the growth, yield and total alkaloid content of ashwagandha roots were increased favourably by the combined application of Azospirillum and phosphobacteria followed by phosphobacteria alone.