EARLY AND RAPID SCREENING OF SUGARCANE CLONES FOR DROUGHT STRESS TOLERANCE USING HYDROPONICS

Abstract

Background: Drought is a major abiotic stress severely affecting sugarcane production in India, causing yield reductions of up to 49%. To address the lack of rapid screening methods at an early stage, present study evaluated 40 sugarcane genotypes for drought stress tolerance using a hydroponic platform. The seedlings were subjected to control and drought conditions. The drought stress treatment was induced by alternate wetting and drying for 30 days. Systematic measurements of morphological and physiological parameters such as root volume, relative water content (RWC), and canopy temperature were performed. Hydroponic screening revealed a very high genetic diversity among the genotypes. In the presence of water scarcity, plants have shown a drought prevention strategy by maintaining root length and volume, while reducing shoot biomass significantly to reduce transpirational water loss. Physiologically, drought stress decreased RWC and SPAD values while increasing canopy temperature. Genetic analyses revealed minimal variations in phenotypic and genotypic coefficients of variation, as well as strong broad-sense heritability (more than 85%) and significant genetic advance for stress-related characteristics such as shoot length and fresh root weight, indicating additive gene action. Correlation study revealed a substantial positive association between RWC and root volume, confirming that non-destructive measurements such as canopy temperature  are accurate markers of hidden root vigor.   The genotypes Co 14005 and  Co 12005 were found to be drought-tolerant due to their better RWC and root length, whereas Co 775, Co 06002 showed high vulnerability. The study also demonstrates that hydroponic phenotyping is a rapid and effective method for identifying drought-tolerant sugarcane clones, making it a valuable tool for early-generation selection in breeding programs.