Abstract:

The sugarcane variety GT42 is a home-bred variety which is the most widely planted in China. It’s necessary to explore the nitrogen demand of the variety to provide references for the scientific management of the variety in the planting areas. Different nitrogenous levels (CK: 0 kg/hm ², low level: carbamide 150 kg/hm ², 300 kg/hm ², middle level: carbamide 450 kg/hm ², high level: carbamide: 600 kg/hm ², 750 kg/hm ²) were applied to the variety before the tiller stage, and the content of endogenous hormone (GA, CTK, BR and ABA), final yield and sugar content were measured under different nitrogen fertilization level in the tillering stage. The yield under different levels nitrogenous fertilizer from more to less was 150 kg/hm ², 300 kg/hm ², 0 kg/hm ², 450 kg/hm ², 600 kg/hm ², 750 kg/hm ², and the yield at 150 kg/hm ² and 300 kg/hm ² fertilizer level was 5.40% and 2.54% more than the CK, respectively (P<0.01). And the highest yield was in the 150 kg/hm ² of nitrogen fertilization treatment. The sugar content per hectare was in the same order as the yield, but the nitrogen fertilization levels had no effect on sucrose content. The economic benefit in the order from more to less 150 kg/hm ², 0 kg/hm ², 300 kg/hm ², 450 kg/hm ², 600 kg/hm ², 750 kg/hm ². The variation tendency of the content of GA and BR were the same that reached the maximum at 150 kg/hm ² of nitrogen fertilization level and then decreased with the increase of nitrogen fertilization level. The content of ABA was the opposite, increasing with the increase of nitrogen fertilization level. The content of CTK increased first, decreased then and increased finally.

Key words: sugarcane, nitrogen, endogenous hormone, yield