桉树扦插生根和生长性状的QTL定位

Detection of Quantitative Trait Loci Related with Rooting Ability of Cuttings and Growth of Eucalyptus

本研究以1个尾叶桉×细叶桉F1谱系为材料,在亲本遗传图谱上对扦插穗条的根数、最长根长、生根率和根干质量4个扦插生根性状及13、18、46个月生的树高和胸径2个生长性状的数量性状位点(QTL)进行了定位,结果表明:在母本尾叶桉和父本细叶桉上分别检测到6个和7个扦插生根相关的QTL,似然函数比值的对数值(LOD)2.0 3.9,贡献率15.2%26.8%,与最近标记的遗传距离为0.0 15.0 cM;尾叶桉上未检测到显著影响13、18个月生的树高和胸径的QTL,但检测到2个和1个QTL分别为与46月生树高和胸径显著相关;细叶桉上检测到显著影响各林龄树高和胸径的QTL,包括13月生树高和胸径的QTL各4个、18月生树高和胸径的QTL分别为1个和2个以及46月生树高和胸径的QTL各2个。没有检测到与扦插和生长均相关的QTL,表明两类性状可能受不同的基因位点控制。两类性状上均有部分QTL与相邻标记紧密连锁,甚至直接定位到标记上,这为相关性状的标记辅助选择提供了有潜力的候选标记。

An F1 pedigree of Eucalyptus urophylla×E.tereticornis was used to detect quantitative trait loci（QTLs） controlling four cutting-related traits,i.e.number of roots per cutting,the maximum length of roots,percentage of rooted cuttings and root dry weight,as well as two growth traits,height（H） and breast-high diameter（DBH） of 13-,18-and 46-month-old Eucalyptus trees.For cutting-related traits,six and seven QTLs were detected on genetic maps of maternal Eucalyptus urophylla and paternal E.tereticornis,respectively,with logarithm of odds（LOD） ranging from 2.0 to 3.9,variance explained from 15.2% to 26.8% and map distance with the closer flanking marker 0.0 to 15.0 cM.For growth traits,two and one QTLs were detected on the maternal map in 46-month-old H and DBH,respectively,though no QTL was found for 13-or 18-month-old growth,and a number of QTLs were located onto the paternal map for all the ages,including four,four,one,two,two and two QTLs for H13,DBH13,H18,DBH18,H46 and DBH46,respectively.No QTL was found to affect significantly the rooting ability of cuttings and field growth simultaneously,implying probably the difference in genes responsible for the two types of traits.Several markers had zero cM of map distance to or linked very closely with QTL,which might act as sound candidate markers for future marker-assisted selection in related traits.