Identification of brown rust resistance and molecular detection of <italic>Bru1</italic> gene in new and main cultivated sugarcane varieties

Abstract

The aim of this study was to assess brown rust resistance of new sugarcane varieties bred in China and main cultivated varieties in sugarcane planting area, and screen the elite new brown rust resistant varieties for popularization and application in production. In total, 60 new varieties in the national regional test of new sugarcane varieties were tested in Kaiyuan and Lincang, and 34 main cultivated varieties were studied in Lincang, Puer, and Yuxi, Yunnan province, and Yizhou, Guangxi province, China, where the incidence of brown rust was particularly high. The resistance of these sugarcane varieties to brown rust was investigated under natural inoculation and molecular marker-assisted identification was used to detect the brown rust resistance gene Bru1 . The results of field survey showed that 66 (70.21%) of the 94 new and main cultivated varieties were highly resistant to moderately resistant, and 28 (29.79%) were susceptible to highly susceptible. Molecular detection indicated that Bru1 gene was found among 54 (57.45%) of the 94 new and main cultivated varieties. Some main cultivated varieties that were currently planted across large areas such as Guitang 29, Guitang 44, Dezhe 03-83, Liucheng 03-1137, Yuetang 60, and Guitang 46 were highly susceptible to brown rust, and 31 new varieties such as Yuegan 48, Funong 09-2201, Guitang 08-120, Liucheng 09-15, Zhongzhe 1, Yunzhe 08-1609, Yunrui 10-187, and Zhongtang 1201 were resistant. Therefore, in the sugarcane planting areas with high incidence of brown rust and wet and rainy climates, more effort should be eliminated the main susceptible varieties and promoted the application of new resistant varieties. This will help to achieve a reasonable distribution of varieties, fundamentally control the outbreak of disease in sugarcane planting areas, and provide security for the high-quality development of sugarcane industry in China in the future.