我国大陆甘蔗骨干亲本亲缘关系分析

Pedigree analysis of genetic relationship among core parents of sugarcane in China's Mainland

对50多年来我国甘蔗育种计划的骨干亲本进行亲缘关系分析,结果表明,在统计的186个品种中,全部含POJ2878或其姐妹系POJ2725的血缘,65.59%含F134的血缘。21个骨干亲本育成品种数达163个,占87.63%。21个骨干亲本包含了甘蔗属热带种、割手密、印度种和大茎野生种中2～4个种的血缘,它们之间的共祖系数分布在0.012～0.387之间。在以早期引进品种为主要亲本的阶段,骨干亲本间的共祖系数为0.023～0.285,平均为0.133;以自育品种为主的阶段,骨干亲本间的共祖系数明显较高,达0.051～0.307,平均为0.189;在大量利用野生种质创新材料和新引进品种作亲本的阶段,骨干亲本间的共祖系数平均为0.088,亲本结构得到改善。为扩大甘蔗品种遗传基础,宜选用亲缘关系较远的亲本组配杂交组合。亲本间的共祖系数可作为一个评价亲缘关系的指标。

Pedigree analysis of genetic relationship among the core parents of sugarcane used over the past fifty years was conducted. The results indicated that all of the 186 cultivars analysis could be traced back to POJ2878 or its full sib variety POJ2725, and 65.59% of which could be traced back to F134. 163 varieties produced from 21 core parents, accounted for 87.63% of the culfivars analyzed. The core parents descended from remote ancestral parents of two to four species of S. offwinarum, S. spontanteum, S. barbed and S. robustum, and their coancestry coefficients were between 0.012 and 0.387. During the period mainly used th! e early introduced varieties as parents, the coancestry coefficients among the core parents distributed between 0.023 and 0.285, with an average of 0.133. In the following period when many self-bred varieties were used as parents, the coancestry coefficients among the core parents were heightened to 0.051 -0.307,with an average of 0.189. The genetic relationship among parents became much alienated after using some novel clones descended from newly exploited wild germplasm and newly introduced varieties as parents, with a mean coancestry coefficients of 0.088. In order to broaden genetic basis of current cuhivars, parents with farther genetic relationship should be chosen to make crosses, and coancestry coefficients could be employed as a useful tool for assessment of parental genetic relationaship.