[目的]作物野生近缘物种、地方品种以及利用它们创制的育种原始种质,具有大量未被育种利用的遗传变异.但是,由于普遍具有明显缺陷、产量潜力低,育种家不愿意用,从而限制了其大规模应用.育种原始种质的利用效率不高,仍然是亟待解决的重要问题.[方法]根据人工合成六倍体小麦和以地方品种为遗传背景的染色体工程材料的育种实践,总结建立原始种质的高效育种利用技术体系.[结果]建立了"育种原始种质-顶交-两段选择"育种体系,利用小群体选育出7个新品种,同时利用6RS.6AL易位系选育的含黑麦抗白粉病基因Pm56的新品系参加了四川省区域试验.[结论]顶交可以导入原始种质的有利位点、同时改良综合性状,有利于重组累积不同品种亲本中的有利位点、赶上育种家的遗传改良步伐,也有利于原始种质与其他亲本间不同遗传变异的协调匹配.两段选择降低了选择难度、提高了选择效率,尤其是第一段选择聚焦于淘汰遗传上相对简单的关键缺陷性状,选择标准简单、易操作,而且符合中选标准的植株少,从而选择难度小、工作量小.育种实践表明,基于原始种质的小麦育种技术体系提高了育种效率.
[Objective]Crop wild relatives,landraces and the derived primitive germplasm have rich variations that are waiting to be used in crop breeding.However,breeders are reluctant to use them because of the low yield potential frequent deficient in key agronomic traits,thus hindering their breeding application in a large scale.How to increase the use efficiency of primitive germplasm in breeding is still a big problem.[Method]This study tried to develop the breeding system of primitive germplasm from breeding practice by using of synthetic hexaploid wheat and a chromosome engineering material under the genetic background of a wheat landrace.[Result]The breeding system called as'primitive germplasm-top cross-two phase selection'was developed.The application has released seven varieties and developed an elite line that is under the regional variety tests in Sichuan Province,which is a 6RS.6AL translocation line containing the rye-derived powdery mildew resistance gene Pm56.[Conclusion]Top-cross is an effective way to not only introgress beneficial loci from primitive germplasm into wheat but also improve overall traits,favourable to gather beneficial loci existing in different cultivar parents to keep pace with the stepwise genetic improvement achieved by breeders,and favourable to the coordinating and matching of genetic variations in primitive germplasm and cultivar parents each other.The two-phase selection reduces the difficulty of selection and improves the selection efficiency.Especially,the first-phase selection only focuses on discarding deficient in key agronomic traits controlled by major genes.The selection criteria are simple and easy to operate,and the selection workload is small since there are a few plants meeting the criteria.In a word,the primitive-germplasm-mediated breeding system improved breeding efficiency.