小麦单倍体染色体加倍率和加倍植株结实率的细胞学基础

双单倍体（DH）技术正越来越多地整合应用于构建高效育种技术体系、加速育种进程。规模化生产DH是该技术育种应用的基础。通过小麦×玉米杂交途径我们在昆明已实现年产约2万个小麦DH；但从单倍体到DH，平均有1/3的单倍体植株因染色体组未加倍而损失，且加倍植株的结实率普遍较低（平均约30粒/DH），制约了生产效率、增加了单位成本。国内外从染色体加倍处理试剂、时期、浓度、时间等做了大量研究，但改进效果甚微且不稳定。已知秋水仙素通过破坏纺锤丝形成而诱导细胞染色体加倍，但如何稳定高效诱导加倍，其细胞学基础尚不清楚。本项目拟对单倍体不同发育阶段分生组织细胞加倍处理后2n细胞的比率及其与加倍率、结实率的关系，以及分生组织细胞有丝分裂同步处理的前期指数和中期指数变化及其与加倍率、结实率的关系进行比较研究。研究结果有助于拓展对秋水仙素诱导细胞染色体加倍机制的认识，为突破小麦DH规模化生产技术瓶颈提供科学依据。

The double haploid (DH) technology is increasingly being integrated to build the efficient breeding technological system and accelerate the breeding process. Large-scale production of DH is the premise of breeding use of DH techniques. Currently, we can produce about 20,000 wheat DHs yearly at Kunming through wheat × maize system. Hower, during chromosome doubling, about 1/3 of haploid plants were lost due to the failure of chromosome doubling. In addition most doubled plants have lower seed setting rate (at about 30 seeds /DH on average), which restricted the efficiency of DH production and increased the cost. In order to improve such situation, Researches relative with rate of chromosome doubling were done on different chromosome doubling reagents as well as their treatment periods, concentrations, durations, etc. at home and abroad, but the improvement effect is very limited and unstable. Colchicine is known to induce chromosome doubling by disrupting the formation of spindle filaments, but the cytological basis of how to induce doubling steadily and efficiently is not clear. This project intends to analyze the ratio of 2n cells after doubling treatment of meristem cells in different developmental stages of the haploid and its relationship with doubling rate and seed setting rate, as well as the changes of the prophase and metaphase index in mitosis and their relationship with the doubling rate and seed setting rate after the synchronization treatment of meristem cells. The research results are helpful to expand the understanding of the mechanism of colchicine-induced cell chromosome doubling, and will provide a scientific basis for breaking through the technical bottleneck in mass production of wheat DHs.