Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK74078, USA.
Wheat, Peanut and Other Field Crops Research, USDA-ARS, 1301 N Western RD, Stillwater, OK, 74075-2714, USA.
BMC Genomics. 2017 Oct 31;18(1):838. doi: 10.1186/s12864-017-4239-8.
'Apogee' has a very short life cycle among wheat cultivars (flowering 25 days after planting under a long day and without vernalization), and it is a unique genetic material that can be used to accelerate cycling breeding lines. However, little is known about the genetic basis of the super-short life of Apogee wheat.
In this study, Apogee was crossed with a strong winter wheat cultivar 'Overland', and 858 F plants were generated and tested in a greenhouse under constant warm temperature and long days. Apogee wheat was found to have the early alleles for four flowering time genes, which were ranked in the order of vrn-A1 > VRN-B1 > vrn-D3 > PPD-D1 according to their effect intensity. All these Apogee alleles for early flowering showed complete or partial dominance effects in the F population. Surprisingly, Apogee was found to have the same alleles at vrn-A1a and vrn-D3a for early flowering as observed in winter wheat cultivar 'Jagger.' It was also found that the vrn-A1a gene was epistatic to VRN-B1 and vrn-D3. The dominant vrn-D3a alone was not sufficient to cause the transition from vegetative to reproductive development in winter plants without vernalization but was able to accelerate flowering in those plants that carry the vrn-A1a or Vrn-B1 alleles. The genetic effects of the vernalization and photoperiod genes were validated in Apogee x Overland F populations.
VRN-A1, VRN-B1, VRN-D3, and PPD-D1 are the major genes that enabled Apogee to produce the very short life cycle. This study greatly advanced the molecular understanding of the multiple flowering genes under different genetic backgrounds and provided useful molecular tools that can be used to accelerate winter wheat breeding schemes.
“Apogee”在小麦品种中的生命周期非常短（在长日和没有春化的条件下，种植后 25 天开花），它是一种独特的遗传材料，可用于加速循环育种系。然而，人们对 Apogee 小麦超短生命周期的遗传基础知之甚少。
本研究将 Apogee 与强冬小麦品种“Overland”杂交，在温室中对 858 株 F 植物进行了恒温和长日条件下的测试。发现 Apogee 小麦具有四个开花时间基因的早期等位基因，根据其强度顺序排列为 vrn-A1>VRN-B1>vrn-D3>PPD-D1。在 F 群体中，所有这些 Apogee 早花等位基因均表现出完全或部分显性效应。令人惊讶的是，Apogee 在早花方面具有与冬小麦品种“Jagger”相同的 vrn-A1a 和 vrn-D3a 等位基因。还发现 vrn-A1a 基因对 VRN-B1 和 vrn-D3 具有上位性。单独的显性 vrn-D3a 不足以引起未经春化的冬植物从营养生长向生殖生长的转变，但能够加速携带 vrn-A1a 或 Vrn-B1 等位基因的植物开花。春化和光周期基因的遗传效应在 Apogee x Overland F 群体中得到了验证。
VRN-A1、VRN-B1、VRN-D3 和 PPD-D1 是使 Apogee 产生极短生命周期的主要基因。本研究极大地促进了不同遗传背景下多个开花基因的分子理解，并提供了有用的分子工具，可用于加速冬小麦育种计划。
