Occurrence and field evaluation of sugarcane genotypes for resistance to pokkah boeng disease in China

Sugarcane pokkah boeng disease (PBD), caused by a Fusarium species complex, is one of the most critical diseases causing a significant economic loss of sugarcane production in China. It is important to standardize the evaluation method for screening sugarcane cultivars for resistance to PBD. Field trials were conducted to investigate the occurrence of sugarcane PBD in different months and growth stages from 2018 to 2019 and to evaluate the PBD resistance of 169 sugarcane genotypes from 2019 to 2022. PBD mainly occurred in the early and middle elongation stages at a plant height of approximately 1-2 m. The most severe and common incidence of PBD was from June to August. Variance analysis showed genotype, year and the interaction of genotype and year had a significant effect on disease incidence and disease index. The 169 sugarcane genotypes were divided into five categories by cluster analysis and discriminant analysis, of which 33 were rated as highly resistant, 37 as resistant, 38 as moderately susceptible, 26 as susceptible and 35 as highly susceptible. These findings enhance our understanding of sugarcane resistance to PBD and lay the foundation for breeding new resistant varieties.