Screening and Evaluation of Fifteen Sugarcane Varieties for Drought Resistance

Sugarcane production in China is severely constrained by frequent seasonal droughts, especially in the major planting region of Guangxi. Identifying drought-resistant varieties is crucial for ensuring yield stability. This study aimed to comprehensively evaluate the drought resistance of 15 sugarcane varieties and screen key identification indicators. A pot experiment was conducted with both well-watered (control) and drought-stress treatments. Fifteen agronomic and physiological traits were measured, and drought resistance was assessed using the comprehensive drought resistance evaluation value (D value), the comprehensive drought resistance coefficient (CDC), and the weighted drought resistance coefficient (WDC). Results showed significant variations in trait responses to drought: green leaf number (NGL) decreased the most (66.06%), while proline (Pro) increased the most (88.09%). PCA reduced 15 traits to 5 principal components, with a cumulative variance contribution rate of 82.26%. Comprehensive evaluation using D values, comprehensive drought resistance coefficients (CDCs), and weighted drought resistance coefficients (WDCs) showed consistent overall drought resistance rankings, with slight differences in individual varieties. Cluster analysis based on D values classified the 15 varieties into three groups: 10 drought-resistant (66.67%, e.g., YZ08-1609, LT5), 3 moderately drought-resistant (e.g., GT08-56), and 2 drought-sensitive (GT10-612, ZT13-012). Grey relational analysis identified single stalk weight (SSW), number of leaves (NL), and number of green leaves (NGL) as key indicators closely associated with drought resistance. This study provides a scientific basis for establishing a drought-resistant sugarcane variety evaluation system and lays the foundation for breeding drought-resistant varieties.