Occurrence and Field Evaluation of Promising Sugarcane Genotypes for Resistance to Midrib Red Rot Disease in China

Sugarcane midrib red rot caused by Colletotrichum falcatum is widespread in China. Standardizing the resistance evaluation methods and screening resistant varieties against this disease is crucial. C. falcatum was determined as the causal agent of midrib red rot by isolating and identifying pathogenic fungi from diseased leaves in Guangxi, China. A field trial of 237 sugarcane genotypes was conducted for three consecutive years to investigate disease incidence and indices for three experimental sites in Guangxi. The combined analysis of variance showed that disease incidence was significantly affected by genotype, year, location and their interactions. Cluster and discriminant analysis showed that 237 sugarcane genotypes were classified into five categories, including 20 as highly resistant, 82 as resistant, 71 as moderately susceptible, 46 as susceptible and 18 as highly susceptible. This study has enhanced our understanding of sugarcane resistance to midrib red rot, selected disease-resistant parents and laid the foundation for developing elite disease-resistant varieties.