Abstract:

‘ROC22’ was the most important sugarcane cultivar in Guangxi sugarcane production from 2008 to 2017. In this study, the performances of the agronomic traits of ‘ROC22’ in the regional trials of the new sugarcane cultivars in Guangxi during this period were investigated, combined with the analyses of its production performance, the changes in its planting area and economic benefit, to provide a reference for sugarcane breeding and cultivation. The tillering and ratoon-shooting ability of ‘ROC22’ declined with year increase while the plant height and stalk diameter fluctuated in a certain degree. Since 2012, the average productivity of ‘ROC22’ had been decreasing continuously, and its sucrose content also has been declining in a certain degree, especially declined more dramatically in November. The smut incidence rate had risen rapidly from 2.94% to 9.02%, and this disease had become the most important disease in Guangxi sugarcane production. The borer damage degree had been getting heavier year by year, and the rate of heart-withered shoots has risen from 2.29% to 4.27%. The planting area of this cultivar reached a peak in 2011, and then began decreasing rapidly, from 756.4×10³ hm² to 255.9×10³ hm², or 69.5% to 31.6% in proportion. The Guangxi farmers’ income from planting this cultivar decreased from 34.04 billion RMB in 2011/2012 milling season to 11.52 billion RMB in 2017/2018 milling season. It was concluded that ‘ROC22’ has contributed greatly to the development of Guangxi cane sugar industry as the main sugarcane cultivar for many years, but its characters have been degenerated dramatically with the increasing of planting years, its damage by pests and diseases has been heavier, and cane yield and sucrose content has been decreased considerably, so it will be unavoidable to be replaced by other new elite cultivars.

Key words: sugarcane, variety, ROC22, commercial character, distribution change