甜玉米果皮厚度QTL的定位及上位性互作  

Mapping and Epistatic Interactions of QTLs for Pericarp Thickness in Sweet Corn

作　　者：于永涛[1] 李高科[1] 祁喜涛[1] 李春艳[1] 毛笈华[1] 胡建广[1] 

机构地区：[1]广东省农业科学院作物研究所/广东省农作物遗传改良重点实验室,广东广州510640

出　　处：《作物学报》2015年第3期359-366,共8页Acta Agronomica Sinica

基　　金：广东省教育部产学研结合项目(2012B091100467);广东省自然科学基金重点项目(080021003)资助

摘　　要：果皮厚度是影响甜玉米口感的一个重要因素。发掘果皮厚度的基因资源、了解玉米果皮厚度的遗传机制,是指导其育种的基础。本研究以日超-1(薄果皮,56.57μm)×1021(厚果皮,100.23μm)的190个BC1F2家系为作图群体,分别采用2种遗传模型检测QTL。基于复合区间作图(CIM)共检测到3个影响果皮厚度的QTL,位于3.01、6.01、8.05区段,分别解释8.6%、16.0%和7.2%的表型变异,其中3.01和8.05处QTL以加性效应为主;基于混合线性CIM模型(MCIM)共检测到5个影响果皮厚度的QTL,其中除8.05处QTL为加性QTL外,另有2对加×加上位性互作QTL,1对是2.01和6.05处QTL之间的互作,另1对则是5.06和6.01处QTL间的互作。这2对互作QTL分别解释了6.63%和12.48%的表型变异率。本结果表明,加性效应和上位性互作效应等都在果皮厚度的形成和遗传中起重要作用。能够检测QTL上位互作的MCIM模型更适用于果皮厚度QTL定位。本研究还在其中4个QTL的区域内分别检索到胚乳中色素合成以及细胞转变的相关候选基因,这些基因的表达是否与果皮厚度的变异有关值得进一步研究。Pericarp thickness is of great importance to the sensory quality of sweet corn. Mining the gene for pericarp thickness and understanding its genetic mechanism can provide a base for instructing breeding. Quantitative trait locus （QTL） for pericarp thickness was detected based on two genetic models using a population comprising 190 BC1F2 families derived from the cross of Richao-1 （thin pericarp, 56.57μm） ×1021 （thick pericarp, 100.23μm） in the present study. Three QTLs for pericarp thickness were identified on bin 3.01, 6.01, and 8.05 using the Composite interval mapping （CIM） method, explained 8.6%, 16.0%, and 7.2% of phenotypic variation, respectively. Based on the MCIM （mixed-model based CIM） method, we identified five QTLs for pericarp thickness, comprising one additive QTL and two pairs of epistatic QTLs. The additive QTL was located on bin 8.05. Additive × additive epistatic effects for pericarp thickness were showed between QTL in 2.01 and QTL in 6.05 with estimated 6.63% of the phenotypic variation and between QTL in 5.06 and QTL in 6.01 with the estimated phenotypic variation of 12.48%. The results indicated that epistasis and additive effects play an important role in the genetic basis of pericarp thickness. The MCIM model with the ability to detect epistatic QTLs is more suitable for pericarp thickness QTL mapping. In addition, candidate genes encoding proteins that play important role for pigment biosynthesis and cell transformation in endosperm were contained in four QTL regions of all, suggesting the likely relations between the expressions of these candidate genes and pericarp thickness variation.

关 键 词：甜玉米 果皮厚度 QTL 上位性互作 

分 类 号：S513[农业科学—作物学]