芒属植物分蘖数性状的QTL定位

芒属植物是一种多年生C₄高大禾草,是一种重要的生物能源作物。分蘖是芒属植物重要的农艺性状之一,在调控其产量方面具有极其重要的作用。以五节芒和荻的种间杂交群体为材料,利用前期已构建的五节芒和荻的种间基因组遗传连锁图谱,结合2014年泰安、2015年泰安和东平3次重复调查的分蘖数表型数据,进行该重要性状的QTL遗传定位研究。结果表明:分蘖数频率分布呈现正态连续分布,符合数量性状遗传的特征;采用MQM复合区间作图法共定位到16个与分蘖数性状相关的QTL,单个QTL可解释的表型变异范围为11.4%~21.5%,LOD值为3.06~6.09。其中,3个QTL在3次定位分析中可重复检测到,qmfTI-2可分别解释12.7%、12.0%和15.5%的表型变异,qmsTI-1可分别解释12.0%、12.1%和19.8%的表型变异,qmsTI-2可分别解释21.5%、20.2%和13.4%的表型变异;3个QTL在2次定位分析中可重复检测到,qmfTI-1、qmfTI-3和qmsTI-4分别解释12.4%和11.4%、13.8%和13.2%、12.1%和14.3%的表型变异。通过对芒属植物分蘖数性状QTL分析,为芒属植物种质资源改良、分子标记辅助选择以及遗传学研究奠定基础。

QTL analysis of tiller number in Miscanthus

Miscanthus is a tall, perennial plant of the grass family, with highly efficient C₄ photosynthesis and therefore has potential to become an important bioenergy crop. Tiller number is one of important agronomic traits of Miscanthus and plays an extremely important role in yield regulation. We used two established interspecific genetic linkage maps of Miscanthus floridulus and M. sacchariflorus for quantitative trait locus (QTL) analysis of tiller number, together with the tiller number phenotype data from Tai'an in 2014, 2015 and Dongping in 2015. Results showed that the frequency of the tiller number phenotype followed the normal distribution of continuous variation, according with the hereditary characteristics of quantitative traits. A total of sixteen QTLs were identified for tiller number using a multiple-QTL model. The single QTLs explained 11.4%-21.5% of the phenotypic variation and the logarithm of odds (LOD) values of these QTLs ranged from 3.06 to 6.09. Three of the QTLs were detected repeatedly 3 times: qmfTI-2 explained 12.7%, 12% and 15.5% of the phenotypic variation, qmsTI-1 explained 12%, 12.1% and 19.8% of the phenotypic variation and qmsTI-2 explained 21.5%, 20.2% and 13.4% of the phenotypic variation. Three of the QTLs were detected twice, of which qmfTI-1, qmfTI-3 and qmsTI-4 explained, respectively, 12.4% and 11.4%, 13.8% and 13.2%, and 12.1% and 14.3% of the phenotypic variation. Through the QTL analysis of tiller number of Miscanthus, our study provides a good foundation for molecular marker-assisted breeding and improvement of Miscanthus germplasm resources.