WITHDRAWN: Bio-hardening of in vitro raised plants of Geneva (G.) series clonal rootstocks of apple (Malus X domestica Borkh.)

Abstract

Background:The success of tissue culture-raised plantlets lies in their transfer from in vitro to in vivo phase as the step of hardening helps to improve the adaptive behavior of in vitro grown plantlets to the natural environment. But the overall success rates are quite low. ResultsThe present research has been done through bio-inoculation of two apple clonal rootstocks viz., G.41 and G.214 during hardening with Phosphate Solubilizing bacteria(B1) containing Azotobacter chroococcum and Bacillus polymyxawith four concentrations prepared by dissolving 1.0 ml,2.0ml,3.0ml and 4.0ml liquid formulation of Phosphate Solubilizing bacteria solution separately in 10.0 ml distilled water and adding that mixture to ellepot medium with cocopeat moss and Vascular Arbuscular Mycorrhiza (B2) containing mycorrhizal propagules @ 60 spores/g with four concentrations prepared by dissolving 1.0 mg,2.0mg,3.0mg and 4.0mg powdered formulation of Vascular Arbuscular Mycorrhiza separately in 10.0 ml distilled water and adding that mixture to ellepot medium with cocopeat moss. Conclusion: After comparing two different bio-inoculants on two different rootstocks, it was found that out of the two rootstocks,G.41 showed maximum hardening with 4.0 ml of Phosphate Solubilizing bacteria than G.214.Meanwhile, G.214 depicted maximum hardening rates with 2.0 mg of Vascular Arbuscular Mycorrhiza than G.214.Thus, a protocol has been standardized for improving the hardening success under in vivo conditions for commercial purposes in both rootstocks.