【作者】 王兰珍；

【导师】 毛达如；

【作者基本信息】 中国农业大学 ， 植物营养学， 2003， 博士

【摘要】 缺磷是小麦生产的重要限制因素之一，改良小麦的磷营养效率可经济有效地解决这一问题。本研究通过2年的田间试验，利用磷效率（低磷产量）和对低磷的敏感度（缺磷引起的减产程度）对216份冬小麦种质的磷营养效率进行鉴定，同时利用选出的典型材料对磷效率基因型差异的生理基础和磷效率的遗传特点进行探讨，以期为磷效率改良工作提供材料和理论上的依据。主要结果如下： （1）通过两年的田间试验从216份冬小麦种质中选出一批磷效率和产量潜力表现稳定的材料，它们包括高产高效品种CA9325和农大139，低产低效品种农大116、冀麦23和20120223。田间试验表明，以产量为基础的磷效率年度间稳定性较差，只有37.8％的品种是稳定的，因此多年的连续鉴定对典型磷效率材料的获得十分重要。在试验中还发现小麦的株高、产量三因素组成特点以及由缺磷引起的抽穗期变化与小麦的磷营养效率有关，通过对有关农学性状的了解有助于更快更准的获得典型的磷效率材料。研究发现，缺磷条件下扬花期的生物量、光合叶面积和成熟期的成穗数、穗粒数与小麦的磷效率相关性较高，可能成为筛选磷高效材料的次级选择指标。 （2）大田条件下，应用相关分析和通径分析法对12个冬小麦基因型的磷营养效率进行分析，结果表明，磷吸收效率和磷利用效率对磷效率都有较大的贡献，但磷吸收效率对磷效率的贡献更大。进一步分析表明，磷利用效率主要在籽粒形成阶段对磷效率起作用，而磷吸收效率在整个生长发育过程中都对磷效率有重要的作用。 （3）以3个磷效率不同的冬小麦品种为材料，研究冬小麦磷效率基因型差异的原因。结果发现，磷高效品种在缺磷条件能维持其独特的产量结构优势，总体而言，与磷低效品种相比，磷高效品种在缺磷条件下具有分蘖两极分化速度快，单穗发育好，扬花后合成光合产物能力强的特点。与此同时，产量结构不同的磷高效品种在适应低磷环境方面也表现出了各自不同的特点。磷缺乏条件下，大穗型的磷高效品种CA9325能更好的维持次生根在扬花后的发育，因而在扬花后可获得更多的磷用于籽粒的发育；多穗型的磷高效品种农大139能在扬花前累积较多的磷，在扬花后不再具备吸磷优势，但有较高的磷利用效率，因此最大限度的降低了缺磷对籽粒产量的不良影响。 （4）利用品种群体和临旱6210×晋麦17的F₂代群体研究了磷效率的广义遗传力，结果表明磷效率的广义遗传力在品种群体中较高（63％），在F₂群体中较低（20％）。表明冬小麦的磷效率是受多基因控制的数量遗传性状，因而在磷效率改良过程中对磷效率的早代选择效率较低。更多还原

【Abstract】 Phosphorus (P) deficiency is one of the principal yield-limiting factors in wheat production. Improving P efficiency genetically can be one of the promising ways to deal with this problem.In this study, 216 wheat genotypes were evaluated for their P nutritional efficiency under field condition. Phosphorus nutritional efficiency was measured by P efficiency (yield at low P level) and sensitivity to low P (yield decrease caused by P deficiency). Then some genotypes were chosen to investigate the physiological basis contributing to genetic variations of phosphorus efficiency. The main results were as follows:1 Two high P efficient varieties with high yield potential, CA9325 and Nongdal39, and three low P in-efficient varieties with low yiled potential, Nongdall6, 20120223 and Jimai23, were selected from 216 winter wheat genotypes through two-year field experiments. During the two years tests, only 37.8% of the tested cultivars had stable P efficiency, indicating that, in order to get P efficient germplasm more quickly and more exactly, it was necessary to characterize for several years. The plant height, heading time delayed by P deficiency, and sturcture of yield components were related to P nutritional efficiency. The results also indicated that biomass, leaf area at anthesis and grains per ear at severe P deficient condition (Olsen P=2.4mg-kg-1) or ears per centiare at slight P deficient condition (Olsen P=6.6mg-kg"’) may be taken as the secondary criterion in selecting for P efficient cultivars.2 The relationship between P efficiency and P absorption efficiency and P utilization efficiency was analyzed with 12 winter wheat cultivars under field condition. By path analysis, it was found that both P absorption efficiency and P utilization efficiency had direct roles in P efficiency, but the role of P absorption efficiency was greater than P utilization efficiency. The results also indicated P utilization efficiency was important after anthesis, but P absorption efficiency was important during the whole growth period.3 Three cultivars with different P efficiency were used to analyze the physiological base attributed to genotypic variations in P efficiency. The results showed that P efficient cultivars could maintain their predominance in then- yield structure and have three common characters in P deficiency status. They were quick dying of invalid tillers, well-developed ear and more dry matter production after anthesis in P deficiency status. Phosphorus efficient cultivars with different yield structure also had their special physiological characteristics. The cultivar CA9325, with few tillers but big ears, succeeded in maintaining its secondary root growth after anthesis so that it absorbed enough P for grain development in this growth stage. The cultivar Nongdal39, with numerous tillers, accumulated more P before anthesis. After anthesis, P upatke of this cultivar was low while P utilization efficiency was high.4 The broad sense heritability of P efficiency is high (63%) when it was analyzed in the population composed of cultivars. This figure was low (20%) when it was analyzed in the F2 population derived from Linghan 6210 X Jinmai 17. It was supposed that P efficiency is controlled by quantitative genes, and the selection for P efficiency in early generation is ineffcient in breeding for P efficient cultivars.更多还原