Morphological and Physiological Responses Of Banana (Musa sp.) Genotypes Subjected to Drought Stress

Abstract

The nutritional and economic value of bananas (Musa spp.) makes them one of the most important fruit crops globally and highly valued. Banana plants have extensive root systems for water and nutrient uptake but are highly susceptible to drought stress, which affects the plant's growth, physiological performance, as well as productivity. This study aimed to evaluate the impact of different watering frequencies: watering 8x/month (L1), 4x/month (L2), 2x/month (L3), 1x/month (L4), on the morphophysiological responses and drought tolerance of three Musa genotypes, including Cavendish (V1), Tanduk (V2), and Pisang Awak (CV3), was investigated, in experiment one, while experiment two was the continuation of the selected drought treatment (L3) to test wild banana (Musa acuminata) genotype tolerance. The experiment was conducted under greenhouse conditions using a nested experimental design with three replications. Four watering frequencies were imposed over two months: eight times per month (L1, well-watered control), four times per month (L2), twice per month (L3), and once per month (L4). Watering frequency was treated as the main factor, while genotype was nested within each watering treatment. Morphological parameters, including plant height, leaf number, pseudostem diameter, biomass, root length, root number, and leaf area, were measured together with physiological characteristics such as photosynthetic rate, stomatal conductance, intrinsic water-use efficiency (iWUE), chlorophyll fluorescence, chlorophyll content, stomatal density, and relative water content. Biochemical indicators, including malondialdehyde (MDA) and proline content, as well as plant survival percentage, were also determined. Results show that frequency of watering had a dramatic impact on most of the morphological, physiological, and biochemical characteristics. Plants subjected to L3 and L4 were severely impacted by drought, experiencing low growth, reduced biomass accumulation, low photosynthetic activity, and inadequate chlorophyll fluorescence compared to plants grown under L1 and L2. Different genetic varieties responded to moderate drought differently. When the stress was moderate (L3), Pisang Awak (V3) performed better according to morphological attributes, while Cavendish (V1) did considerably well when well-watered (L1). When stressed by drought (L4), Pisang Tanduk (V2) performed better than Cavendish (V1) in physiological processes, whereas all three varieties behaved similarly under L3. Among the tested treatments, treatment L3, watering twice a month, was found to be the most effective in inducing drought stress in the bananas and was suitable for evaluating drought tolerance. Under treatment L3, visible drought symptoms in the plants were observed three to four weeks after treatment. Keywords: chlorophyll fluorescence, malondialdehyde, net photosynthesis, proline, relative water content