Evaluation of Light Emitting Eiode (LED) on the in-vitro performance of selected east African highland banana cultivars

Abstract

Tissue culture has been identified as a technology that has the potential to provide large quantities of clean planting materials all year round. Up to 500 banana plantlets can be obtained from one sucker in a year. However, the current cost of a tissue culture-derived plantlet is $0.9 which is too high for a smallholder farmer. Part of the cost is attributed to the energy used for lighting and cooling taking a reasonable percentage of the production costs. In-vitro plant propagation uses artificial growth factors to maintain asepsis in the laboratory setting among others and light. Conventional florescent lights are used in growth rooms to provide lighting to the cultures offering general spectra for growth and 30% is converted into energy for the plants to utilize while 70% is converted into heat. This generated heat that can only be regulated by running air conditioners to be able to attain the optimum temperature required for banana culture growth. The present study aimed to investigate the optimum light intensity of the new combinations of LED light as compared to the white light spectrum for banana morphogenesis in terms of multiplication rates, chlorophyll content, and survival rates at the post-flask handling stage. Three replicates of meristematic tissues used as cultures were maintained in a growth room at 27±2°C, under LED light with spectral combinations of ultraviolet, blue, green, red and far red in the following percentages A (0,14,15,54,17); B (0,12,19,61,8); C (1,21,38,36,6) and D as control was under white fluorescent light. Results show no significant effect in terms of buds’ multiplication across treatments but treatment B for specific genotype Kisansa, indicated higher rates of buds. Shoots showed a higher multiplication rate at treatment C with genotype Nabio 808 than others. Roots development showed more long roots on treatment A on genotype Kisansa while short roots where indicated on treatment A on genotype Bogoya. Chlorophyll content production varied among treatments but the highest was attained at light treatment C on genotype Kisansa, followed by light treatment B on genotype Mpologoma. At the post-flask handling stage, all three treatments showed 98.5 % survival in the acclimatization and hardening phase compared to white light. Therefore, use of LEDs for micro-propagation of the EAH banana will be adopted due to its superiority compared to conventional fluorescent white light for spectral specificity, long operational duration and reductions in energy investment although significant differences were not realised at some growth stages.