西瓜果实总糖含量QTL分析

【目的】为了探讨西瓜果实中总糖含量的遗传规律并找到与总糖含量相关的QTL位点,【方法】以高糖品系‘花园母本’为母本,低糖品系‘LSW-177’为父本,配制杂交组合,构建含有180个单株的F2代群体,分别测量成熟西瓜果实中心和边缘部分果糖、蔗糖和葡萄糖含量,并将3者之和相加作为总糖含量进行遗传图谱构建及QTL分析。【结果】构建的遗传连锁图谱共包含45个SSR标记,分属于13个连锁群,覆盖基因组长度为547.3 cM,标记间平均距离为12.44 cM,检测到与中心和边缘总糖含量相关的QTL位点各一个,均为加性遗传效应,贡献率分别为6.56%、7.90%,分布在第3、12连锁群上,LOD值分别为3.1、3.29,找到与中心和边缘总糖含量紧密连锁的标记4个(MU8184-3、MCPI-12、TJ116、MU8558-3),该研究结果为进一步开展西瓜糖含量相关基因定位和克隆研究提供理论依据。【结论】西瓜果实总糖含量为数量性状遗传,由多基因共同控制,中心部分总糖含量QTL位点表现为正向加性效应,边缘部分总糖含量QTL位点表现为负向加性效应。

QTL analysis for total sugar content in watermelon

【Objective】 The aim of this research is to elucidate the genetic regularity and find the QTLs of total sugar content in watermelon.【Method】 The 180 F2 population derived from two watermelon inbred lines,'Garden Female Parent' and 'LSW-177',the 'Garden Female' Parent with high sugar content as the female parent was crossed with the low sugar contented line 'LSW-177' which served as the male parent,were employed to map and analyze quantitative trait locus associated with total sugar content in watermelon in the experiment.The content of fructose,sucrose and glucose in both middle part and edge part was measured respectively.Additive quantity of the three kinds of sugars was used as the total sugar content to construct the linkage map and to analysis the QTLs associated with total sugar content in watermelon.【Result】 The results show that,a genetic map with 45 SSR markers and 13 linkage groups was developed,which spanning 547.3 cM with a mean marker interval of 12.44 cM.Two QTLs associated with sugar content were detected both in middle and edge part.The 2 QTLs distributed in 3,12 linkage groups respectively,and they were all additive effects.Their LOD values were 3.1,3.29 respectively.The 2 QTLs were able to explain 6.56%,7.09% of total phenotypic variation.Four SSR markers(MU8184-3,MCPI-12,TJ116,MU8558-3) were detected which associated with the total sugar content in watermelon.These SSR markers linked to QTL could provide the reference data for gene location and sugar content gene cloning in watermelon.【Conclusion】 The studies suggested that the total sugar content exhibited an obvious characteristics of quantitative character inheritance,controlled by the poly-gene.The QTL associated with middle part shows additive effect and the QTL associated with edge part shows negative effect.