基于连锁-关联分析剖析玉米茎秆糖相关性状遗传基础

Stalk sugar content (SSC) at a time and the transporting amount of stalk sugar at a growth stage are closely related to dry matter accumulation of maize ear. Previously reports showed that corn stalk sugar content is different in different growth stages. In this study, we investigate seven related traits (total stalk length(TSL), number of nodes(NN), the length from bottom node to ear node (LBE), stalk diameter(SD), ear fresh weight(EFW), ear dry matter weight(EDMW), and milk line position ratio(MPR)) at five different growth stages in six different environments (2 years, 3 locations) among two different kinds of population (association analysis population and RIL population). Based on the these phenotypic data, we analyzed the relationship between corn ear yield and stalk, stalk sugar content, and stalk sugar transportation. By using ultra-high density bin markers and SNPs, we will identify the QTLs and candidate association locus dissecting the genetic basis of regulation of stalk sugar content-related traits, which are correlated with maize ear dry matter accumulation. And fine mapping these major QTLs. Our finding should be significant to benefit maize high-stalk sugar and high-yielding breeding.

茎秆糖含量及茎秆糖运输量与玉米果穗干物质形成积累密切相关。研究表明玉米不同生育时期的茎秆糖含量不同。本研究以2个群体（关联群体、齐319与掖478衍生的重组自交系群体）为材料，在2年3点6个环境下，自玉米雄穗始花期开始测定5个不同生育时期，茎秆糖相关性状（玉米茎秆全茎长、茎节节数、穗茎长、穗茎粗、果穗的鲜重、干重和籽粒乳线位置）的表型数据，分析玉米茎秆、茎秆糖含量及茎秆糖运输与果穗干物质形成积累的关系。借助高密度bin marker遗传图谱和SNPs标记，利用连锁-关联分析方法，明确茎秆糖相关性状的主效QTL数目、位置及遗传效应；在分子水平上阐明玉米茎秆、茎秆糖含量及茎秆糖运输与果穗干物质形成积累的关系，为玉米茎秆高糖及高产的分子标记育种提供基础。

玉米茎秆是玉米植株的重要组成部分，研究玉米茎秆相关性状遗传基础是玉米茎秆相关性状改良及新品种培育的前提。本研究基于连锁-关联分析方法挖掘控制玉米茎秆性状的数量位点，主要研究结果如下：1.多环境条件下鉴定一致性特异玉米种质46份，为我国玉米茎秆性状改良及新品种培育提供材料基础；2.明确我国常用玉米自交系类群茎秆特征：Lan茎节较少，Reid茎秆较粗，PB茎秆较细，LRC茎秆较粗、茎节较短，SPT植株较矮、茎秆含糖量较低、干物质含量较低；为玉米杂种优势育种提供理论参考；3.获得8个解释茎秆状总变异10%以上的QTL，鉴定6个热点QTL区段，挖掘3个候选基因；4.鉴定44个显著SNPs，3个SNP热点区域，1个候选基因；本研究为茎秆相关基因的精细定位及克隆奠定基础，为玉米株高、产量、抗倒伏能力及机械化收割等茎秆相关性状改良及新品种培育提供重要的理论参考及实践指导。