Enhancing nitrogen (N) use efficiency (NUE) is crucial for the sustainable production of potatoes (Solanum tuberosum L.). The aims of this study were to assess i) the genotypic variation of the main components of NUE (N utilization efficiency (NUTE) and N recovery efficiency (NRE)), ii) the association between these components, related traits, and cultivars, and iii) the usefulness of N nutrition index (NNI) to assess NUTE and NRE of potato genotypes grown under different levels of N availability. Two field experiments were carried out in Chile during the season 2021–2022. Treatments were the combination of 15 potato cultivars and three rates of N (0, 200, and 400 kg N ha−1). High variations were observed in total dry matter biomass (DM) (5.9–22.1 Mg ha−1), tuber DM biomass (5.1–18.3 Mg ha−1), total N concentration (1.01–2.24 %), total N uptake (98–323 kg ha−1), NUTE (35–91 kg tuber DM kg−1 N), and NRE (−14–54 %). Total N uptake was significantly related to total DM biomass and traits related to N concentration and N uptake. In both experiments, strong negative correlations were observed between total N concentration and NUTE (r = −0.95 – −0.98). Also, NUTE and N harvest index were positively correlated. The relationship between NUTEtub and NNI was well described (p < 0.01; R2 = 0.55–0.87) by a negative power function. The predicted average of NUTEtub for a NNI = 1 (optimal N status) showed a narrow range (49.5–56.9 kg DM kg−1 N). Both relative tuber yield and relative total biomass were significantly related to NNI (R2 = 0.56 and 0.66). The cultivar Desiree, Karu-INIA, and Shepody were among the cultivars with the highest NNI. A significant positive relationship (p < 0.01; R2 = 0.42) was observed between NRE and NNI. This study demonstrates the effectiveness of the NNI in evaluating and interpreting NUTE and NRE based on genotype and nitrogen supply, ultimately enhancing decision support for improving NUE in potato production systems.

中文翻译：

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氮营养指数作为评估马铃薯基因型氮利用效率的工具


提高氮 （N） 利用效率 （NUE） 对于马铃薯 （Solanum tuberosum L.） 的可持续生产至关重要。本研究的目的是评估 i） NUE 主要成分（氮利用效率 （NUTE） 和氮回收效率 （NRE））的基因型变异，ii） 这些成分、相关性状和栽培品种之间的关联，以及 iii） 氮营养指数 （NNI） 评估在不同氮有效性水平下生长的马铃薯基因型的 NUTE 和 NRE 的有用性。2021-2022 赛季在智利进行了两次田间试验。处理是 15 个马铃薯品种和 3 种氮用量（0、200 和 400 kg N ha-1）的组合。总干物质生物量 （DM） （5.9-22.1 Mg ha-1）、块茎 DM 生物量 （5.1-18.3 Mg ha-1）、总氮浓度 （1.01-2.24 %）、总氮吸收 （98-323 kg ha-1）、NUTE（35-91 kg 块茎 DM kg-1 N）和 NRE （-14-54%）。总氮吸收与 DM 总生物量显著相关，性状与 N 浓度和 N 吸收相关。在这两个实验中，观察到总氮浓度与 NUTE 之间存在很强的负相关 （r = -0.95 – -0.98）。此外，NUTE 和 N 收获指数呈正相关。NUTEtub 和 NNI 之间的关系得到了很好的描述 （p < 0.01;R2 = 0.55–0.87） 的 R2 = 0.55–0.87）。NNI = 1 （最佳 N 状态） 的 NUTEtub 预测平均值显示范围狭窄 （49.5-56.9 kg DM kg-1 N）。块茎相对产量和相对总生物量均与 NNI 显著相关 （R2 = 0.56 和 0.66）。栽培品种 Desiree、Karu-INIA 和 Shepody 是 NNI 最高的栽培品种之一。显著的正相关 （p < 0.01;R2 = 0.42） 在 NRE 和 NNI 之间观察到。 本研究证明了 NNI 在基于基因型和氮供应评估和解释 NUTE 和 NRE 方面的有效性，最终增强了对改善马铃薯生产系统中 NUE 的决策支持。