两种产量水平下超级杂交稻氮素吸收利用特性

Characteristics of nitrogen absorption and utilization of super hybrid rice grown under two yield levels

  • 摘要: 探明不同产量水平下超级杂交稻的氮素吸收利用特性, 可为我国西南稻区超级杂交稻高产栽培和育种提供理论和实践依据。以2个超级杂交稻品种(‘德优4727’ ‘泸优727’)和2个高产常规稻品种(‘金农丝苗’ ‘黄华占’)为材料, 于2018—2020年在四川省德阳市(高产点)和泸州市(中产点)两个生态点进行大田和盆栽试验, 研究两种产量水平下超级杂交稻氮素吸收、转运及利用效率的差异。结果表明: 大田条件下不同生态点间超级杂交稻产量、氮素吸收积累利用特性差异显著。高产点超级杂交稻产量、氮肥偏生产力较中产点分别增加8.3%~23.2%、8.3%~23.1%。高产点超级杂交稻播种(SO)—幼穗分化(PI)、PI—齐穗(HD)阶段氮素吸收量和氮素吸收速率(除2018年幼穗分化—齐穗外)均高于中产点, HD—成熟(MA)阶段仍保持较高的氮素吸收量。高产点超级杂交稻成熟期氮素总吸收量较中产点增加15.6%~33.7%。尽管高产点超级杂交稻氮素收获指数较中产点平均增加4.6% (2018年除外), 但成熟期仍有大量氮素滞留在超级杂交稻的秸秆中, 造成高产点氮素籽粒生产效率较中产点平均减少11.3%。方差分析表明, 盆栽条件下土壤、土壤×地点、土壤×品种互作对超级杂交稻产量、氮素吸收量、氮素籽粒生产效率影响不显著。高产点盆栽超级杂交稻产量、氮素吸收量、氮素籽粒生产效率变化趋势与大田试验相似。高产点SO—PI平均温度高于中产点, HD—MA平均温度低于中产点; 高产点SO—PI、PI—HD和HD—MA太阳辐射积累量(除2018年PI-HD外)均高于中产点。相关分析表明, 高产点籽粒产量与PI—HD氮素吸收量、氮素收获指数呈显著正相关; 氮素籽粒生产效率与SO—PI的氮素吸收量和平均温度呈显著负相关。中产点籽粒产量与氮素籽粒生产效率、总吸氮量呈显著正相关; 氮素籽粒生产效率与SO—PI和HD—MA的平均温度呈显著负相关。因此, 不同产量水平超级杂交稻产量和氮素吸收利用特性差异主要与不同生育期内的平均温度和太阳辐射有关。

     

    Abstract: This study aims to investigate the characteristics of nitrogen (N) uptake and utilization in super hybrid rice grown under two yield levels to provide a theoretical and practical basis for super high-yield rice cultivation and super hybrid rice breeding in southwest China. Field and pot experiments were conducted in Deyang City (a high-yielding site, HYS) and Luzhou City (a medium-yielding site, MYS) between 2018 and 2020. Each year, two super-hybrid rice cultivars (‘Deyou4727’ and ‘Luyou727’) and two high-yielding inbred rice cultivars (‘Jinnongsimiao’ and ‘Huanghuazhan’) were planted at each site. Differences in N uptake, translocation, and utilization characteristics between the two yield levels and the four rice cultivars were studied. The results showed marked differences in grain yield, N uptake, and utilization between the two sites in the field experiment. Super-hybrid rice produced higher grain yield and partial factor productivity of applied N (PFPN) in HYS in comparison to those in MYS by 8.3%−23.2% and 8.3%−23.1%, respectively. Super-hybrid rice exhibited higher N uptake and rate of N uptake from sowing (SO) to panicle initiation (PI) and PI to full heading (HD) in HYS in comparison to MYS (except for the duration from PI to HD in 2018). However, HYS demonstrated higher N accumulation during the grain-filling period of super-hybrid rice. Consequently, super-hybrid rice demonstrated 15.6%−33.7% higher total N uptake in HYS in comparison to MYS. On average, despite HYS showing a 4.6% higher N harvest index in super-hybrid rice compared to MYS (except in 2018), a substantial amount of N was still retained in the straw at the maturity stage. Consequently, HYS demonstrated 11.3% lower N use efficiency for grains production (NUEGP) than MYS. Analysis of variance revealed that the effects of soil, the interactions of year (Y)×soil (S), S×location (L), and S × cultivar (C) were not significant for grain yield, N uptake, or NUEGP of super-hybrid rice grown in the pot experiments. The trends in grain yield, N uptake, and NUEGP of super-hybrid rice grown in the pot experiments were similar to those in the field experiments. HYS experienced a higher mean temperature during the SO-PI phase, whereas the mean temperature was lower in HYS compared to MYS. The cumulative solar radiation during SO-PI, PI-HD, and HD-MA was higher in the HYS than in the MYS (except for PI-HD in 2018). Further analysis indicated that rice grain yield was significantly and positively related to N uptake accumulation during PI-HD, as well as the N harvest index in the HYS. There was a significant negative relationship of NUEGP with N uptake accumulation, and mean temperature during the SO-PI in the HYS. There was a significant positive relationship between rice grain yield and NUEGP and total N uptake in the MYS. Additionally, NUEGP was significantly negatively correlated with mean temperature during the SO-PI and HD-MA in the MYS. Our findings indicated that the differences in grain yield, N absorption, and utilization characteristics of super-hybrid rice at different ecological sites are primarily related to the climatic factors (including mean temperature and solar radiation during the growing season) of the planted site.

     

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