南方水稻氮素吸收与利用效率的基因型差异及评价

GENOTYPIC DIFFERENCES AND VALUATION IN NITROGEN UPTAKE AND UTILIZATION EFFICIENCY IN RICE

以南方籼型水稻(Oryza sativa)品种为试验材料进行大田试验,以探讨提高水稻氮素吸收与利用效率的基因型潜力。结果表明,除早季分蘖期氮素积累量、干物质生产效率和抽穗期氮素积累量以及晚季氮素运转效率外,各基因型氮素吸收与利用效率存在显著或极显著的差异,提高水稻氮素吸收与利用效率的基因型潜力很大。基因型生育期对其氮素吸收与利用效率产生重要影响,生育期较长的基因型其氮素吸收效率、稻谷和干物质生产效率以及农艺效率较高。杂交稻氮素的生产效率、农艺效率、回收效率和收获指数较常规稻高,但二系杂交稻并没有比三系杂交稻明显提高。通过排序方式对各基因型氮素吸收与利用效率进行评价的结果表明,不同氮素吸收与利用效率指标的排序以及同一指标早晚季的排序均存在较大差异。氮素吸收与利用效率经标准化后的综合排序可对各基因型的氮素吸收与利用效率进行综合评价,吻合系数则可较好地反映各基因型早晚季氮素吸收与利用效率的排序。

The low price of rice has placed farmers in a cost-price squeeze, and extravagant nitrogen application in rice agriculture has resulted in a decrease in nitrogen uptake and utilization efficiency and serious environmental pollution. This has caused scientists to pay more and more attention to rice nitrogen uptake and utilization efficiency. These field experiments were conducted using indica hybrid rice ( Oryza saliva ) to explore the genetic potentiality of increasing nitrogen uptake and utilization efficiency. Seven parameters of nitrogen uptake and utilization, TNA (Total nitrogen accumulation) , NDMPE (Nitrogen dry matter production efficiency) , NGPE (Nitrogen grain production efficiency), NTE (Nitrogen transportation efficiency), NHI (Nitrogen harvest index), NAE (Nitrogen agronomy efficiency) and NRE (Nitrogen recovery efficiency), were measured. Results showed that there were significant or highly significant differences in these seven parameters a-mong genotypes, except for TNA and NDMPE at tillering of early season rice, TNA at heading of early season rice and NTE at late season rice. Long growth duration could increase TNA, NDMPE, NGPE, and NAE. NDMPE, NGPE, NAE, NRE and NHI for hybrid rice were higher than for inbred rice. The seven parameters of two-line hybrid rice and three-line hybrid rice were almost equal at early season, and NGPE, NHI, NAE, NRE and TNA of two-line hybrid rice were smaller than that of three-line hybrid rice at late season. This indicated that both nitrogen uptake and utilization efficiency of two-line rice were not increased. Ranking methods were employed in order to make an exact valuation for nitrogen uptake and utilization efficiency of genotypes. Ranking results indicated that there were great differences among different parameters and between early and late season rice in the same parameter. The genotypes were ranked according to the means of the seven parameters after standard transformation, which provided a way for comprehensive valuation of nitrogen uptake and utilization efficiency of the genotypes. Considering the difference in integration ranking of genotypes at early and late season, a coincidence index (square root of means of square of integration ranking difference of identical genotypes at early and late season) was employed to evaluate the coincidence degree of integration ranking of genotypes at early and late season. Results showed that, of 30 genotypes, integration rankings of ' Zhongyou 253', ' Zaoxiang 1' , ' Guyou 11' and ' 653%' at early and late season coincided well, and of the seven parameters, integration rankings of NDMPE at early and late season coincided well.