基于重组自交系群体水稻氮素利用效率分析和利用

Analysis of rice nitrogen use efficiency based on recombinant inbred line population

  • 摘要: 本文以水稻重组自交系群体为试验材料, 设置不施氮与施低氮(150 kg.hm-2)两种处理的大田试验, 研究了水稻重组自交系群体氮素吸收利用及主要农艺性状分布特征, 并通过相关、聚类、主成分等统计方法阐明性状间的相互关系, 为氮素高效利用水稻新品种培育提供理论依据。结果表明, 水稻重组自交系群体的氮素利用效率性状在施氮150 kg.hm-2条件下的变异系数较大; 施氮促进了群体穗、茎秆、叶氮含量的增加和单株干物质总量(包括单株穗重、单株茎秆重和单株叶重)的提高。在两种氮环境下, 氮素干物质生产效率均与株高、穗长、单株茎秆重、单株干物质总量呈正相关, 与茎秆氮含量、叶氮含量、穗氮含量呈负相关; 氮素籽粒生产效率均与单株谷重、结实率、千粒重、穗总粒数和穗长呈正相关, 与单株茎秆重、叶氮含量、单株叶重、单株氮素积累总量呈负相关。逐步回归分析结果显示, 茎秆氮含量、穗氮含量和单株茎秆重对氮素干物质生产效率影响尤为显著, 而对氮素籽粒生产效率影响更为显著的是穗数、穗总粒数与结实率。主成分分析表明, 氮利用效率较高时, 植株体内氮含量较低, 尤其是茎秆的氮含量。因此, 在大田低氮条件下, 要注重筛选植株较高、茎秆较重的重穗型(穗较长, 穗总粒数较多, 结实率较高)株系; 且具有较低茎秆与穗氮含量, 尤其是较低的茎秆氮含量, 将有利于氮高效利用水稻新品种的选育。从中选出的氮高效品系如Q149与氮低效品系Q114等优良品系13份, 可作为优质资源研究使用。

     

    Abstract: Nitrogen is the most critical input limiting rice productivity. Due to increasing fertilizer costs and environmental concerns, nitrogen use efficiency (NUE) is hotly debated in the scientific community. To explore the absorption, utilization and main traits distribution patter of nitrogen in recombinant inbred lines (RILs), a field experiment was conducted to evaluate potential NUE of rice (Oryza sativa L.). The split-plot experiment had two treatments (one without nitrogen fertilizer and the other with 150 kg.hm-2 of nitrogen) for populations of RILs, the parents and the check line Q149. The relationship between NUE and the main agronomic characteristics of RILs population was determined using statistical correlation, clustering, principal component analyses. The results showed that the variation coefficient of NUE was larger under 150 kg.hm-2 nitrogen treatment than under non-nitrogen treatment. Proper increase in nitrogen fertilization was beneficial to nitrogen content in rice panicle, stem and leaf, and to total dry matter weight of single plant. Significantly positive correlations were noted between dry matter production efficiency and plant high, panicle length, stem weight per plant, total dry matter weight of single plant under two nitrogen treatments. Also under both treatments, significantly negative correlations were noted between dry matter production efficiency and the contents of nitrogen in rice stem, leaf and panicle. There were positive correlations between grain production efficiency and grain weight per plant, seed setting rate, thousand-seed weight, total number of grains per panicle, and spike length. Equally, there were negative correlations between grain production efficiency and stem weight per plant, leaf nitrogen content, leaf weight per plant and total amount of nitrogen per plant. Stepwise regression analysis indicated that nitrogen content in stem and panicle, and stem weight per plant had significant effects on dry matter NUE. However, the effects of number of panicles per plant, number of grains per panicle and seed setting rate on grain NUE were more significant in the two treatments. Principal component analysis showed that the nitrogen content in rice plant, especially in stem, decreased with increasing of NUE. Therefore, in low-nitrogen field, it was necessary to select heavy-panicle type variety that was high in stem weight (including long panicle length, more grains per panicle and high seed-setting rate) in breeding programs. Furthermore, lower nitrogen content in stem and panicle (especially in stem) benefited the breeding for high NUE. Based on the study, 7 rice lines with high NUE (e.g., Q149) and 6 lines with low NUE (e.g., Q114) were selected for special germplasm in rice breeding projects.

     

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