Bio-Acclimatization of In Vitro Propagated Banana Plantlets 'Grand Nain'

With the commercial advent of tissue culture technique, primary hardening profiles of banana plantlets are monitored by examining (i) their % survival as a function of bio-fertilizers application, (ii) profiles of root ramification and colonization by VAMs and (iii) profiles of height & girth, leaves & chlorophyll content, leaf surface area, etc. The significant findings are: (i) The plantlets applied with nitrogen fixer and PSM at 1 g/plant and VAMs at 2 g/plant in conjunction with peat (G(1) medium), gave more than 97% survival. (ii) These plantlets also exhibited an optimal root length and number of primary roots, not observed in plantlets applied with other varying combinations of nitrogen fixer, PSM and VAMs. (iii) These plantlets had maximum 55-78% root colonization by VAMs. (iv) The monitored parameters were almost unanimous in their choice of G1 as an optimal primary hardening medium on the basis of other morphological features, such as height & girth, leaf & chlorophyll content. Primary hardening study is followed by secondary hardening, where optimization of growth medium has been made on the basis of parameters monitored as above. The significant findings are: (i) Growing plantlets in polybag medium containing soil: PMC: vermicompost in a ratio of 1:1:1 (v/v/v) fortified with N-2 fixer, PSM and VAM (S-1 medium) helped increasing in % survival of plantlets after transplantation by 14%. (ii) The same medium was also helpful in producing plantlets with optimum root length, number, root mass and % VAM colonization. (iii) It also produced more number of leaves, leaf length/width as well as chlorophyll content. (iv) It also permitted more uptake of macro-and micro-nutrients, cumulatively signifying the role of PMC and vermicompost in the growth of banana plantlets during secondary hardening. Secondary hardening study is followed by field trials by monitoring the profiles of (i) soil pH and TVC, (ii) organic carbon content and VAM spore count, (iii) % plant survival & root colonization by VAM, (iv) height and girth, (v) leaves and chlorophyll content, (vi) macro-and micro-nutrients uptake, (vii) yield attributing characters and (viii) actual yield. Its salient observations are: (i) There was a decrease in the soil pH as a function of bio-fertilizer application to the banana plantlets which also promoted TVC and VAM spore count in the soil. (ii) The hardened plants performed optimally in terms of biometric parameters (as judged by height, girth, leaves and chlorophyll content) with 50% reduced chemical fertilizer application. (iii) Macro-and micro-nutrients uptake in the leaves increased in the bio-fertilized plants as compared to non-bio-fertilized ones. (iv) The same trend was witnessed in yield attributing characters (number of fingers per hand, number of hands per bunch and bunch weight). (v) Sensory evaluation of banana pulp reflected nutritional quality of banana for consumers, sustainable productivity of banana for farmers and eco-friendly approach for the society. These observations are a direct reflection of VAM activity.