甜玉米氮素吸收利用的基因型差异

以近年来育成的22个甜玉米品种为材料，在同一供氮水平下对其氮素吸收利用的基因型差异进行了研究。结果表明，不同品种产量、氮素积累量和氮素利用效率都存在着显著差异。氮素积累量变幅为126.6～243.8 kg/hm2，鲜果穗和鲜子粒氮素利用效率的变幅分别为43.5～62.0 kg/kg和28.4～46.0 kg/kg。聚类分析结果看出，鲜果穗、鲜子粒均表现为高产、氮素积累量大、氮素利用效率高的品种是金凤5号、穗美9701和金师王，其氮素积累量均值为214.4kg/hm2，鲜果穗和鲜子粒的氮素利用效率分别为50.8kg/kg和38.2kg/kg。通径分析表明，氮素积累量对不同品种产量的作用大于氮素利用效率对产量的作用，说明鲜食甜玉米品种的高产关键在于改良品种的氮素积累量，并在此基础上提高氮素的利用效率。

Genotypic differences in nitrogen uptake and utilization of sweet maize

Twenty-two varieties of sweet maize (Zea mays L. saccharata Sturt) released recently in China were used in this study to evaluate their genotypic differences in nitrogen (N) uptake and N utilization efficiency (NUE) under the same N fertilization condition. The results indicated that fresh ear and kernel yield, N uptake, and NUE were significantly different among varieties. The range for N uptake was 126.6−243.8 kg/ha, and the range of NUE for fresh ear and kernel was 43.5−62.0 kg/kg and 28.4−46.0 kg/kg, respectively. The results of cluster analysis indicated that three varieties (JF5, SM9701 and JSW) had high yield, N uptake and NUE for both fresh ear and fresh kernel. Average N uptake was 214.4 kg/ha, and average NUE for fresh ear and kernel was 50.8 kg/kg and 38.2 kg/kg, respectively. By path analysis, it was found that the effect of total N uptake on yield was far greater than the effect of NUE on yield. So the improvement of total N uptake was crucial for improving fresh ear and kernel yield of sweet maize, which was the basis to increase NUE.