Influence of plant growth regulators on phenology, growth and root yield of ashwagandha (withania somnifera (l.) dunal.)

Research experiments were conducted to investigate the effect of growth regulators on phenology, growth and yield of Ashwagandha / Winter Cherry [Withania somnifera (L.) Dunal.) during late rainy seasons 2008-09 and 2009-10 at Research Farm, College of Horticulture, Mandsaur (M.P.) India. The results revealed that spray of IBA 100 mg.l-1 effected maximum delay in floral initiation, 50 per cent flowering, 50 per cent fruiting; first fruit maturity and physiological maturity as compared to other growth regulators viz. MH, BA, Ethrel and water spray (control). There was no generalized specific trend found in LAI with respect to different growth regulators during crop growth stages SLA was maximum with IBA 150 mg.l-1, while SLW was maximum with BA 30 mg.l-1. MH 100 mg.l-1 and BA 30 mg.l-1 were found equally effective and the best treatments in increasing RGR and CGR during flowering (60-90DAS), while IBA 50mg.l-1 was the best responding spray for RGR and CGR enhancement during fruiting to physiological maturity at (90-150 DAS). Growth regulators did not produce any definite trend in LWR and LAR but MH 100 mg.l-1 is the best in increasing LWR and LAR in general. Spray of BA 10 mg.l-1and IBA 100 mg.l-1increased leaf persistence (LAD) in the crop, while that of BA 40 mg.l-1 and MH 100 mg.l-1 individually got maximum BMD. IBA 50 mg.l-1 produced maximum plant height (41.27 cm) while MH 250 mg.l-1 was highly effective in suppressing plant height (31.40 cm) as compared to other treatments. Sprays of IBA 100/150 mg.l-1 and Ethrel 100/150 mg.l-1 individually were very effective in increasing root length while BA spray suppressed the root length. IBA 100mg.l-1 and BA 40 mg. l-1 were found equally effective in producing the maximum root yield (11.45 q/ha) which was 37.45% higher than control.