PDF(Pubmed)
Abstract：
The potential for gene flow between cultivated species and their weedy relatives poses agronomic and environmental concerns, particularly when there are opportunities for the transfer of adaptive or agronomic traits such as herbicide resistance into the weedy forms. Grain sorghum (Sorghum bicolor) is an important crop capable of interspecific hybridization with its weedy relative johnsongrass (Sorghum halepense). Previous findings have shown that triploid progenies resulting from S. bicolor × S. halepense crosses typically collapse with only a few developing into mature seeds, whereas tetraploids often fully develop. The objective of this experiment was to determine the impact of S. bicolor genotype and pollen competition on the frequency of hybridization between S. bicolor and S. halepense. A total of 12 different cytoplasmic male sterile S. bicolor genotypes were compared with their respective male fertile lines across 2 years, to assess the frequency of hybridization and seed set when S. halepense served as the pollinator parent. Results indicate significant differences in the frequency of interspecific hybridization among the S. bicolor genotypes, and pollen fertility in S. bicolor reduced the rate of this interspecific hybridization by up to two orders of magnitude. Further, hybridization rates greatly varied across the two study environments. Results are helpful for developing appropriate gene flow mitigation strategies and indicate that gene flow could be reduced by the selection of appropriate seed parents for sorghum hybrids.
摘要：
栽培物种及其杂草近缘种之间的基因流动的可能性引起了农艺和环境问题。特别是当有机会将适应性或农艺性状如除草剂抗性转移到杂草形式时。谷物高粱（Sorghumbicolor）是一种重要的作物，能够与其杂草相关的约翰逊草（Sorghumhalepense）进行种间杂交。先前的发现表明，三倍体后代来自双色链球菌×S。halepense杂交通常会崩溃，只有少数种子发育成成熟的种子，而四倍体通常完全发育。该实验的目的是确定双色链球菌基因型和花粉竞争对双色链球菌和黑斑链球菌之间杂交频率的影响。在2年内，将总共12种不同的细胞质雄性不育双色S。以评估当S.halepense作为传粉者亲本时杂交和结籽的频率。结果表明，双色链球菌基因型之间的种间杂交频率存在显着差异，双色链球菌的花粉育性使种间杂交的速率降低了两个数量级。Further,两种研究环境的杂交率差异很大.结果有助于制定适当的基因流缓解策略，并表明通过为高粱杂种选择合适的种子亲本可以减少基因流。
