为筛选蓝莓(Vaccinium spp.)氮高效品种及探究不同蓝莓品种幼苗的适宜施氮水平，本研究以长江流域4个蓝莓主栽品种‘莱格西’(‘Legacy’)、‘绿宝石’(‘Emerald’)、‘优瑞卡’(‘Eureka’)和‘蓝美1号’(‘Lanmei 1’)为实验材料，通过盆栽实验，设置不施氮(0.000 g·kg^-1)、低氮(0.214 g·kg^-1)、中氮(0.429 g·kg^-1)和高氮(0.857 g·kg^-1) 4个处理，分析不同施氮水平下不同蓝莓品种幼苗农艺性状及氮素利用效率的差异。结果显示：‘莱格西’和‘绿宝石’属于低氮高效型，‘优瑞卡’属于中氮高效型，‘蓝美1号’属于氮高效型。随着施氮水平的提高，4个蓝莓品种幼苗的单株干质量增加量，株高，冠幅，基径，叶片叶绿素相对含量，根、茎、叶和单株氮素增加量，以及单株磷素增加量总体呈上升趋势；单株分枝数和单株钾素增加量呈先上升后趋于稳定的变化趋势；氮素效率、氮素吸收效率和氮素生理利用效率总体呈先上升后下降的变化趋势；根冠比则总体呈下降趋势。相关性分析结果显示：在不施氮和3个施氮水平下，蓝莓幼苗的氮素效率与单株干质量增加量、茎氮素增加量、单株氮素增加量、单株磷素增加量、单株钾素增加量、氮素吸收效率均呈显著（P＜0.05）或极显著（P＜0.01）正相关。综合分析结果表明：‘蓝美1号’为氮高效品种，可作为氮高效遗传改良种质资源；单株干质量增加量可作为蓝莓氮素利用效率评价的重要指标；氮高效品种‘蓝美1号’和中氮高效品种‘优瑞卡’幼苗的推荐施氮水平为0.429 g·kg^-1，低氮高效品种‘莱格西’和‘绿宝石’幼苗的推荐施氮水平为0.214 g·kg^-1。

To screen nitrogen high efficient cultivars of blueberry (Vaccinium spp.) and explore the appropriate nitrogen application level for seedlings of different blueberry cultivars, four major cultivated blueberry cultivars in the Yangtze River Basin, namely ‘Legacy’, ‘Emerald’, ‘Eureka’, and ‘Lanmei 1’ were taken as experimental materials in this study, and by setting four treatments namely no nitrogen application (0.000  g·kg^-1), low nitrogen (0.214  g·kg^-1), medium nitrogen (0.429  g·kg^-1), and high nitrogen (0.857  g·kg^-1), the differences in agronomic characters and nitrogen use efficiency of seedlings of different blueberry cultivars under different nitrogen application levels were analyzed through the pot experiment. The results show that ‘Legacy’ and ‘Emerald’ belong to the low-nitrogen high efficient type, ‘Eureka’ belongs to the medium-nitrogen high efficient type, and ‘Lanmei 1’ belongs to the nitrogen high efficient type. With the increase of nitrogen application level, the increment of dry mass per plant, height, crown width, basal diameter, relative chlorophyll content in leaf, nitrogen increments in root, stem, leaf, and individual, and phosphorus increment per plant of seedlings of four blueberry cultivars show a tendency to increase in general; the branch number per plant and potassium increment per plant show a variation tendency to first increase and then tend to be stable; the nitrogen efficiency, nitrogen uptake efficiency, and nitrogen physiological utilization efficiency show a variation tendency to first increase and then decrease in general; the root/shoot ratio shows a tendency to decrease in general. The correlation analysis result shows that under the conditions of no nitrogen application and three nitrogen application levels, the nitrogen efficiency of blueberry seedlings shows significant (P＜0.05) or extremely significant (P＜0.01) positive correlations with increment of dry mass per plant, nitrogen increment in stem, nitrogen increment per plant, phosphorus increment per plant, potassium increment per plant, and nitrogen uptake efficiency. The comprehensive analysis result indicates that ‘Lanmei 1’ is a nitrogen high efficient cultivar, and can be used as a nitrogen high efficient germplasm resource for genetic improvement; the increment of dry mass per plant can be used as an important index for evaluating nitrogen use efficiency in blueberry; the recommended nitrogen application level for seedlings of nitrogen high efficient cultivar ‘Lanmei 1’ and medium-nitrogen high efficient cultivar ‘Eureka’ is 0.429 g·kg^-1, and that for seedlings of low-nitrogen high efficient cultivars ‘Legacy’ and ‘Emerald’ is 0.214 g·kg^-1.