Objective The study was conducted to explore the rules of growth and water requirement of diseasefree sugarcane original seedlings, and provide a reference for the field breeding and water management of disease-free sugarcane original seedlings.

Method In this study, by analyzing the dry matter accumulation rule of the diseasefree sugarcane seedlings with the meteorological data of Guangxi Fusui Experimental Base, the crop coefficient method was used to calculate the water requirement and water deficit in each growth period of the disease-free sugarcane original seedlings in Fusui County, Guangxi.

Result The dry matter accumulation of the disease-free sugarcane seedlings was mainly concentrated in the growth period of stem elongation. The stem elongation stage started from mid-August to the end of October, with an average daily dry matter accumulation of 2.92 g. After November, the average daily dry matter accumulation rate decreased to 1.77 g, and about 15 healthy stems could be harvested in late December. The water requirement of diseasefree sugarcane original seedlings showed a decline trend after an initial ascent. In the period of mid-August to late September, the water requirement was the largest, and the daily water requirement reached 5.5 mm. During the growth periods of the disease-free sugarcane original seedlings, the rainfall at the Fusui test site in Guangxi was mainly concentrated from mid-July to mid-September, with a cumulative rainfall of 177.9 mm, and less rainfall from late September to December, with a cumulative rainfall of only 22.3 mm. The disease-free sugarcane original seedlings showed water surplus only at the seedling stage, and the water deficit continued from late July to December, with a total deficit of 473.4 mm.

Conclusion Through the above analysis, the dry matter accumulation characteristics and water requirement rules of the disease-free sugarcane original seedlings were clarified, which provided theoretical basis and references for rational cultivation and scientific irrigation in the field breeding and large-scale production of disease-free sugarcane original seedlings in the future.