Drought tolerance evaluation of intergeneric hybrids of BC3F1 lines of Saccharum officinarum × Erianthus arundinaceus

Abstract

Drought stress is a major determinant of sugarcane crop production in China. However, modern commercial sugarcane cultivars, due to their relatively narrow genetic base, are very susceptible to water deficit. Consequently, drought tolerance is an important breeding target for sugarcane improvement in China. We conducted a study to investigate the drought tolerance of 30 BC3F1 lines of Saccharum offcinarum and Erianthus arundinaceus intergeneric hybrids. Eight physiological indices, namely root viability, content of soluble protein, soluble sugar, proline and malondialdehyde (MDA), and the activities of the free radical scavenging enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), were measured under the drought condition. The results showed that in response to drought the root viability of all BC3F1 lines decreased while the content of soluble protein, soluble sugar, proline and MDA and the activities of SOD, POD and CAT increased. To assess genotypes, we established a comprehensive value (D) based on various measured physiological parameters and root viability. BC3F1 lines were further characterized by principal component analysis and cluster analysis. Based on the D values, 30 BC3F1 lines and the control ROC22 were categorized into three groups: strong, moderate and weak drought tolerance, respectively. More than 50% of the test population showed strong drought tolerance, while about 10% of the BC3F1 lines were highly susceptible to water deficit. This study provides a practically useful method for evaluating drought tolerance in sugarcane and identifies BC3F1 lines with a strong drought tolerance attribute that can be used for developing improved commercial sugarcane cultivars through breeding.