基于SSR标记的大花序桉全同胞子代鉴定

SSR-based identification of full-sib seedlings in Eucalyptus cloeziana F.Muell.

【目的】利用SSR标记鉴定大花序桉1株母本自由授粉的共计2184株子代的父本,为基于全同胞子代群体的遗传分析、图谱构建和数量性状定位等研究提供基础材料。【方法】以母本所在的种源/家系试验林的其他所有706株大花序桉作为候选父本,利用前期优化的12个可多重检测的SSR标记,对包含母本在内的所有样品进行毛细管电泳分型检测。基于最大似然法估算真实父本的概率进行父本鉴定,检测父本花粉的传播距离,计算全同胞群体中12个标记的分离比例(χ^(2)),估算观测杂合度(Ho)、期望杂合度(He)和多态性信息量(PIC)等多样性参数及其与苗高生长的相关。【结果】所有标记可有效扩增和分型检测。1697株(77.7%)子代鉴定了明确的父本,子代130株以上的主要父本有6个、单个父本的子代数量为138~395个;花粉散布的距离较远,可达160 m,但有效花粉的散布距离主要在100 m以内。对子代数量10株以上的7个全同胞家系,12个标记均存在不同程度的偏离期望的孟德尔分离比例;H_(o)和H_(e)等多样性参数较低,其与苗高和苗高变异系数的相关均不显著,本实验未发现有自交现象。【结论】本研究对大花序桉1株母本的自由授粉子代进行了父本鉴定,为后续基于全同胞家系的遗传测定、遗传图谱构建和数量性状位点定位等研究提供了物质材料。

【Objective】To provide full-sib plant materials for genetic analysis,map construction and quantitative trait locus detection in Eucalyptus cloeziana F.Muell.,SSR markers were used to identify paternal parents of an open-pollinated half-sib family(2184 sibs)originating from a superior maternal tree.【Method】The whole 706 trees other than the maternal tree retained in the field trial were treated as candidate paternal parents.Twelve SSR markers optimized earlier for multiplexed genotyping were used to investigate all the parents and sibs by capillary electrophoresis.Paternal parents were determined with the method of maximum likelihood,and then the pollen dispersal distance was estimated.Marker segregation ratio(χ^(2))within each full-sib family identified was estimated,and polymorphism parameters,including observed heterozygosity(Ho),and expected heterozygosity(He),and their correlations with 4-month-old seedling height were calculated for full-sib families.【Result】All the SSR markers can be amplified and genotyped effectively.Of the 2184 half-sibs,1697(77.7%)were identified with definite paternal origin,with six paternal parents each contributing to 138–395 full-sibs.Pollen dispersal distance can reach up to 160 m,with the relatively effective range of 100 m.For the seven fullsib families each containing more than 10 seedlings,most SSR markers were more or less distorted in allelic segregation from the Mendelian segregation expectations;Ho and He were low,and their correlations with seedling height and its coefficient of variation were non-significant.No selfing phenomenon was found in this study.【Conclusion】Paternal parents were determined for an open-pollinated half-sib family of E.cloeziana.The full-sib families identified will provide useful plant material for further genetic test,genetic map construction and quantitative trait locus detection.