【作者】 周桂林；

【导师】 余四斌；

【作者基本信息】 华中农业大学 ， 作物遗传育种， 2009， 硕士

【摘要】 光合作用是作物产量最主要的能量来源,水稻籽粒中80%以上的碳水化合物来自顶二叶的合成,叶片大小是决定光合产物总量的一个重要因素。因此,对功能叶尤其是剑叶形态和大小的遗传分析对于提高作物产量十分重要。目前,有关水稻叶片大小QTL被精细定位或基因鉴定的报道较少。本研究以ZS97B/9311回交重组自交系鉴定的叶片大小相关QTL为基础,利用其衍生的F₂分离群体以及近等基因系（F₃重组单株家系和F₄纯合基因型家系）,对叶片大小QTL进行了重复鉴定和精细定位,旨在分析叶片大小及其与产量相关性的遗传机理,为水稻株型育种和高产育种提供一定的理论和实践依据。主要结果如下:（1） F₂分离群体中,第1染色体RM283-RM8083区间（约20cM）检测到控制剑叶的长、宽、面积,倒二叶的宽、面积以及穗重和二次枝梗数的QTL,证实了该区间存在的QTL多效作用。（2）利用F₃家系均值（矫正F₂单株表型）进行的QTL定位和替代作图表明,RM283-RM8083区间至少存在两个效应区段。第一个是RM151-RM10481区间,该区间能同时控制剑叶的长、宽和面积,倒二叶的长和面积,穗重、穗颖花数和二次枝梗数以及穗长;除剑叶宽和穗长外,该QTL区域对所有考察性状的变异解释率均在15%以上,其中对剑叶长、穗重和穗颖花数的效应最大,分别为32.49%、33.57%和23.04%。第二个是相邻的RM10481-RM5346区间,该区间可控制倒二叶的宽。（3）基于F₃家系基因型分析,挑选其中纯合的单株构建替代系（F₄家系）进行精细定位,结果发现,RM3746-RM10481区间（约7.4cM）内存在一个多效QTL或基因,同时控制剑叶长等多个性状;另外,控制穗重和二次枝梗数的主效QTL被定位于该区间上游的RM10315-RM10346区段,该区段包含已被报道克隆的产量相关基因Gnla。（4） F₄家系中性状相关性分析表明,剑叶长与剑叶的宽、面积,倒二叶的长、面积,抽穗期,穗颖花数、穗重以及二次枝梗数呈显著正相关。一因多效或多基因紧密连锁很可能是这些性状显著相关的遗传基础。更多还原

【Abstract】 Carbohydrates produced by photosynthesis is the primary source of grain yield in rice （Oryza sativa L.）, of which 80% is from the top three leaves. The founctional leaf size is an impotant factor determining the amount of carbohydrates generated by photosynthesis. Thus it is important to genetically analyze the morphological characteristics, such as the leaf size of functional leaves, especially flag leaf in rice improvement. Recently, few genes related to leaf size of rice was reported, and no QTL was fine mapped, though many QTLs were identified by segregant populations. In this study, a F₂ segregating population and two nearly isogenetic line （NIL） populations, heterozygous family （F₃） and homozygous progeny （F₄） developed from some F₂ individuals, were constructed and used to confirm and validate a QTL for flag leaf size on chromosome 1, which was previously detected in a backcross recombinant inbred population derived from a cross between two indica （O. sativa L. ssp. indica） cultivar （ZS97B and 9311）. The objectives of this study were to analyse the genetic bases of leaf size and its relationship with yield components, and to provide useful information for plant-type breeding and yield breeding in rice. The main results are as follows:1. Using a F₂ segregating population, the QTLs for flag leaf length, flag leaf width and flag leaf area; second top leaf width and second top leaf area; panicle weight and number of second branch were detected in the interval of RM283-RM8083 （about 20cM） on chromosome 1, which implied the existing of pleiotropic effect.2. Mean value of each F3 family was used to rectify the phenotype of corresponding F₂ plant for substitution mapping and QTL mapping. The result indicated that in the region of RM151-RM10481 existed a pleiotropic QTL, which could control flag leaf length, width and area; second top leaf length and area; panicle weight, spikelet number, number of second branch and panicle length simutanously. Except for leaf width and panicle length, the variance explaining percentage of the QTL for these traits were all above 15%, and for flag leaf length, panicle weight and second branch number, they were 32.49%、33.57% and 23.04% respectively. Meanwhile in the neighboring region of RM10481-RM5346, a QTL was found for second top leaf width.3. Basing on the genotype analysis of F3 family, homozygous plants were chosen out to construct substitution line- F4 progeny and used for fine mapping. The pleiotropic QTL in the region of RM3746-RM10481 （about 7.1cM） was confirmed and validated controlling length, width and area of flag leaf, length, width and area of second top leaf, heading date, spikelet number, grain weight and panicle length simutanously. While the major QTL for panicle weight and second branch number was located in the interval of RM10315-RM10346, which contained Gn1a ,a cloned gene related yield.4. In F₄ progeny, correlation analysis between the invested traits suggested that flag leaf length was significantly correlated with flag leaf width, flag leaf area, second top leaf length, second top leaf area, heading date, spikelet number, panicle weight, number of second branch. Pleiotropic or tighly linkage of multi-gene may be its genetic basis.更多还原