Response of low nitrogen stress in different sugarcane genotypes.

The aim was to know the ability of different sugarcane varieties in low nitrogen stress.The experimental design was split plot.The treatment of main plot was 300,150 and 0 kg of urea fertilizer applied per acre.The treatment of subplot was composed by five nitrogen fixing sugarcane varieties,and one of Guangxi leading varieties ROC16(CK).The test time of split plot was plant crop and ratoon cane for one year.The result showed that the yield of each plant crop sugarcane was significantly higher than that of ratoon cane,nitrogen cane was significantly higher than nitrogen-free one,the cane yield of nitrogen 300 kg of urea fertilizer applied per acre was not obvious difference with 150 kg.Under three nitrogen level,the cane yield of five varieties new-planting and ratoon sugarcane was significantly higher than that of ROC16(CK).Some aspects of the tested varieties were influenced badly by nitrogen-free,as tillering,ratoon sprouting,internode elongation,shoots.Especially the tillering and productive stem were influenced badly more than the others.The nitrogen-free-resistant and nitrogen-low-resistant ability of each variety form high to low were B8,B9,B5,B1,B3 and ROC16.The result of this test could be given reference for nitrogen fixation and nitrogen efficiency sugarcane breeding and extension in future.