National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Theor Appl Genet. 2015 May;128(5):797-811. doi: 10.1007/s00122-015-2466-4. Epub 2015 Feb 6.
This study explored the genetic constitutions of several wheat- A. cristatum translocation lines and determined the effects of A. cristatum 6P chromosome segments on fertile tiller number in wheat. Progress in wheat breeding is hampered by a relatively narrow range of genetic variation. To overcome this hurdle, wild relatives of common wheat with superior agronomic traits are often used as donors of desirable genes in wheat-breeding programs. One of the successfully utilized wheat wild relatives is Agropyron cristatum (L.) Gaertn (2n = 4x = 28; genomes PPPP). We previously reported that WAT31-13 was a wheat-A. cristatum 5A-6P reciprocal translocation line with higher fertile tiller number and grain number per spike compared to common wheat. However, WAT31-13 was genetically unstable. In this study, we analyzed the 43 genetically stable progenies from WAT31-13 using genomic in situ hybridization, dual-color fluorescence in situ hybridization, and molecular markers. We classified them into three translocation types (TrS, TrL and TrA) and seven subtypes, and also pinpointed the translocation breakpoint. The genotypic data, combined with the phenotypes of each translocation type, enabled us to physically map agronomic traits to specific A. cristatum 6P chromosome arms or segments. Our results indicated that A. cristatum chromosome 6P played an important role in regulating fertile tiller number, and that positive and negative regulators of fertile tiller number existed on the A. cristatum chromosome arm 6PS and 6PL, respectively. By exploring the relationship between fertile tiller number and A. cristatum chromosome segment, this study presented a number of feasible approaches for creation, analysis, and utilization of wheat-alien chromosome translocation lines in genetic improvement of wheat.
本研究探索了几个小麦-冰草易位系的遗传构成，并确定了冰草 6P 染色体片段对小麦有效分蘖数的影响。小麦育种的进展受到遗传变异范围相对较窄的限制。为了克服这一障碍，通常将普通小麦的野生近缘种作为小麦育种计划中理想基因的供体，这些野生近缘种具有优良的农艺性状。成功利用的小麦野生近缘种之一是冰草（Agropyron cristatum (L.) Gaertn）（2n = 4x = 28；基因组 PPPPP）。我们之前报道过，WAT31-13 是一个小麦-冰草 5A-6P 相互易位系，与普通小麦相比，其有效分蘖数和每穗粒数较高。然而，WAT31-13 的遗传不稳定。在本研究中，我们使用基因组原位杂交、双色荧光原位杂交和分子标记分析了来自 WAT31-13 的 43 个遗传稳定后代。我们将它们分为三种易位类型（TrS、TrL 和 TrA）和七种亚型，并确定了易位断点。基因型数据结合每种易位类型的表型，使我们能够将农艺性状物理定位到特定的冰草 6P 染色体臂或片段上。我们的结果表明，冰草染色体 6P 在调节有效分蘖数方面起着重要作用，并且有效分蘖数的正、负调节因子分别存在于冰草染色体臂 6PS 和 6PL 上。通过探索有效分蘖数与冰草染色体片段的关系，本研究为小麦-外源染色体易位系的创造、分析和利用提供了一些可行的方法，以促进小麦的遗传改良。
