As one of the top three tuber crops of the world, cassava is a staple food and feed crop for tropical and subtropical regions. Because of its high drought resistance and tolerance to nutrient deficiency, cassava is usually cultivated on hilly areas that are nutrient-poor. Nitrogen (N) is one of the significant factors affecting cassava yield. A double factorial (N level×genotypes) split-plot field experiment was conducted to analyze differences in yield and N accumulation of 25 cassava genotypes under low-N conditions to screen for cassava genotypes with high-N efficiency. The two-year field experiment showed that cassava yield and N accumulation are determined by specific genotypes, soil N levels, and year. Among these factors, soil N levels are the main factors that are responsible for differences in cassava yield. When yield and relative N accumulation under low-N conditions were used as screening markers, we identified an efficient and responsive genotype (SC10), and two inefficient and non-responsive genotypes (SC205 and GR5). The efficient and responsive genotype and the inefficient and non-responsive genotype can be used as study materials to further reveal the mechanisms for high-N efficiency in cassava.

作为世界上三大块茎作物之一，木薯是热带和亚热带地区的主食和饲料作物。由于木薯具有很高的抗旱性和对养分缺乏的耐受性，因此通常在养分贫乏的丘陵地区种植木薯。氮是影响木薯产量的重要因素之一。通过双因子分解（N水平×基因型）田间试验，分析了在低氮条件下25种木薯基因型在产量和氮素积累上的差异，筛选出具有高氮效率的木薯基因型。两年的田间试验表明，木薯的产量和氮素积累取决于特定的基因型，土壤氮素含量和年份。在这些因素中，土壤氮水平是导致木薯产量差异的主要因素。当在低氮条件下的产量和相对氮素积累用作筛选标记时，我们确定了一个有效和响应性基因型（SC10）和两个无效和非响应性基因型（SC205和GR5）。有效和反应性基因型以及无效和非反应性基因型可以用作研究材料，以进一步揭示木薯高氮效率的机制。