Efficacy of selected microbiological products on growth, health and nutrient uptake of tissue cultured banana in different soils in kenya

Abstract

Banana and plantains are important food crops whose production is constrained by disease and soil fertility. The use of clean planting materials such as tissue cultured banana could mitigate the losses caused by diseases and pests. However, the low survival rate of plantlets during the acclimatization phase is as a major constraint. Inoculation with beneficial microorganisms is one way of protecting tissue cultured plantlets against environmental stresses, thus improving their growth, health and survival. Green house and field experiments were conducted to evaluate the efficacy of selected commercial microbiological products on survival, growth, nutrition and health of tissue cultured banana. Plantlets were grown in soils sampled from three banana growing regions in Kenya; a Vertisol (Western Kenya-Bondo), Rhodic Ferralsol (Coastal Kenya-Kilifi) and a Humic Nitisol (Central Kenya-Meru south) and inoculated with Bacillus, mycorrhizal and Trichoderma based products at the acclimatization and nursery phases of growth. A conventional nursery media from Jomo Kenyatta University of Agriculture and Technology was used as a positive control. Survival of inoculated plantlets was recorded at the 8 weeks after deflasking. Growth parameters were assessed every two weeks under green house conditions and every two months under field conditions up to the flowering stage. A destructive harvest was carried out at the end of the nursery phase. Shoots were analysed for plant nutrient uptake using the inductively coupled plasma method. Root dry weights, root number and total root length were assessed. Soils from the harvested pots were used for assessing the suppression of Fusarium. Inoculation with Bacillus enhanced survival of plants in the Vertisol; mycorrhiza and Trichoderma inoculation in the Rhodic Ferralsol and mycorrhiza in the Humic xix Nitisol and conventional media. Application of Bacillus based products significantly (p≤0.05) increased plant growth in the Vertisol and Rhodic Ferralsol in the nursery phase. Application of multiple species mycorrhiza and Trichoderma under field conditions significantly (p≤0.05) increased apparent volume and leaf surface area in the Vertisol by over 100% and 25% compared to the control and conventional practice respectively. Mixed species Bacillus products significantly (p≤0.05) enhanced uptake of Phosphorous by over 160 and 400% in the Vertisol and Rhodic Ferralsol respectively. Mycorrhiza inoculation enhanced P uptake by over 170% in the Rhodic Ferralsol and Vertisol respectively. Mixed species mycorrhiza and Bacillus significantly (p≤0.05) inoculation enhanced potassium, zinc, iron, manganese, sulphur, copper and magnesium uptake in the Rhodic Ferralsol and Vertisol by over 100%. Suppression of Fusarium oxysporum f.sp. cubense by Bacillus, mycorrhizae and Trichoderma inoculation differed significantly at p≤0.05 within soil types. PHC Biopak, ECO-T and Rhizatech reduced F. oxysporum f.sp. cubense CFU g-1 by 47, 68% and 55% respectively in the Humic Nitisol. ECO-T reduced Fusarium CFU g-1 by 6% in the Rhodic Ferralsol and PHC Biopak by 50% in the Vertisol compared to the non-inoculated soils. Under nursery conditions, combining Rhizatech and Mavuno and ECO-T and manure increased plant growth by over 100% in the Rhodic Ferralsol and Vertisol respectively. Under field conditions, the combined application of Rhizatech and minjingu rock phosphate enhanced plant growth by 57% in the Rhodic Ferralsol while both sole and combined application of products did not significantly affect plant growth in the Vertisol. This study reveals that tissue cultured (TC) banana plant survival, growth, nutrition and health could be improved by commercial microbiological inoculation.