Nitrogen use efficiency and drought tolerant ability of various sugarcane varieties under drought stress at early growth stage

The experiment was conducted under glasshouse conditions to evaluate nitrogen use efficiency and drought tolerant ability of the five different sugarcane varieties (including NiF3, Ni9, Ni17, Ni21 and Ni22) under early growth stage from 60 to 120 days after transplanting. The results showed drought stress reduced the photosynthetic rate, growth parameters including plant height, leaf area; partial and total dry weights; and nitrogen use efficiency (NUE) traits including photosynthetic NUE, nitrogen utilization efficiency and biomass NUE of measured sugarcane varieties. The significant differences were found among varieties in growth parameters, dry weights, NUE traits and drought tolerant index (DTI). The significant positive correlations among NUE traits and DTI suggested higher NUEs could support better a tolerant ability to drought stress at the early growth stage. Because of larger contributions, DTIs for aboveground and stalk dry weight could be used as the important DTIs to evaluate drought tolerant ability in sugarcane varieties. Abbreviations Amax: potential photosynthetic rate; DAT: days after transplanting; DTI: drought tolerant index; NL: specific leaf nitrogen content; NUE: nitrogen use efficiency; NUEb: biomass nitrogen use efficiency; NUEt: nitrogen utilization efficiency; PNUE: photosynthetic nitrogen use efficiency; TN: total nitrogen content; TNU: total nitrogen uptake; WW: well-watered; DS: water stress