Abstract: The research object of this study is 45 wild Saccharum arundinaceum from 7 provinces in China. Under open-pillination conditions,the reproductive characteristics and sexual fecundity of S.arundinaceum were explored by measuring the pollen-ovule ratio (pollen-ovule ratio,P/O),outcrossing index (outcrossing index,OCI) and estimating mating system parameters based on SSR molecular markers,which provided the basis for the development and utilization of S.arundinaceum resources,cross breeding and reproductive technology. The results showed the P/O and OCI of S.arundinaceum were 5 897 and 2 respectively. A total of 11 pairs of SSR (Simple sequence repeats) primers were used to estimate the mating system parameters of 1 158 offspring of 15 S.arundinaceum families sampled randomly. The results showed that the population of S.arundinaceum had a high level of outcrossing rate (t_m=0.864),the difference between the multilocus outcrossing rate and the Single-locus outcrossing rate was not obvious (t_m-t_s=0.012),and the inbreeding coefficient F of parents was greater than 0 (F=0.318),showing that S.arundinaceumm is given priority to with outcrossing,and presence some inbreeding. To sum up,it is preliminarily considered that the reproductive characteristics of S.arundinaceum are mainly outcrossing,supplemented by self-crossing.

Key words: Saccharum arundinaceum, Breeding system, SSR molecular markers, Facultative hybridization

摘要： 本研究以收集自我国7个省的45份野生斑茅(Saccharum arundinaceum)为研究对象,在开放授粉条件下,通过测定斑茅的花粉与胚珠比(Pollen-ovule ratio,P/O)、杂交指数(Outcrossing index,OCI)以及基于简单重复序列(Simple sequence repeats,SSR)分子标记估计交配系统参数这3种方法,探究斑茅繁殖特性及其有性繁殖力的情况,为斑茅资源开发利用、杂交育种及繁殖技术提供基础依据。结果表明:斑茅P/O为5 897,杂交指数OCI为2;采用11对SSR引物对随机取样的15个斑茅半同胞家系共计1 158个子代进行交配系统参数估计,结果显示斑茅种群具有较高的异交率水平(t_m=0.864),多位点异交率和单位点异交率的差值不明显(t_m—t_s=0.012),亲本近交系数F大于0(F=0.318),表明斑茅以异交为主,并存在部分近交。综上所述,本研究初步认为斑茅的繁殖特性为异交为主、自交为辅的混合交配系统模式。

关键词: 斑茅, 繁育系统, SSR分子标记, 兼性异交