Response of Wild and Edible Musa spp. Seedlings to Limiting Moisture Stress

Banana, one of the world's leading crops is predicted to be highly vulnerable to drought conditions brought about by climate change. Identification of drought tolerant cultivars is one of the long term strategies of addressing the effect of climate change. The National Plant Genetic Resources Laboratory and the Bureau of Plant Industry of the Philippine Department of Agriculture maintain germplasm collections of edible and wild Musa spp. from the Philippines, Southeast Asia and Papua New Guinea (SEA/PNG) that have not been assessed for drought tolerance. Thus, this study was conducted to assess the drought response of 29 Musa genotypes from the germplasm collections at seedling stage under greenhouse condition. Drought was imposed on 3 mo-old tissue culture-derived seedlings by withholding water for 2-3 wk, while control plants were watered regularly. Under drought condition, the genotypes differed significantly in terms of plant growth, number of leaf cigars formed, specific leaf area, biomass production and partitioning as well as water use efficiency across water treatment. Only 28% of the banana genotypes allocated more biomass to the roots. Total leaf area production was influenced by significant interaction between water treatment and genotype. Significant genotypic differences in terms of relative leaf folding (RLF) and stomata! conductance were observed, with increased RLF as soil moisture content decreased. Stomatal conductances were significantly affected by the interaction between genotype and time of sampling. The genotypes also differed significantly in their water use efficiency (WUE) with increases ranging 1-70% under drought. WUE was found to be positively correlated with total plant dry weight, root volume, root dry weight and relative leaf folding. Based on the relative performance under drought cultivar, "Gubao" (BBB) is the most drought tolerant based on total biomass production, root dry weight, root volume and WUE followed by 'P.K. Malaccacina" and "Tindok".