Ningmai 9 is a soft wheat cultivar with high and stable yield, broad adaptation, moderate resistance to fusarium head blight (FHB) and high resistance to wheat spindle streak mosaic virus (WSSMV). The ten new wheat cultivars derived from Ningmai 9 have become or will soon be becoming the leading cultivars in the mid-lower reaches of the Yangtze River. In order to explore the value of Ningmai 9 as a crossing parent in wheat breeding program, the physiological basis for high yield and genetic characters for yield, quality and disease resistance of Ningmai 9 were analyzed, meanwhile the main features of its ten derivatives were also described. The results showed that Ningmai 9 had high photosynthetic capacity, water use efficiency and drought resistance, and its high-yielding potentiality was mainly determined by more spikes per unit and grains per spike. The cultivar had high general combining ability in many characters such as grains per spike, harvest index, protein content, alkaline water retention capacity and disease resistance which were easily passed to its derivatives. As a direct parent, the ten excellent cultivars Ningmai 13, Ningmai 14, Ningmai 16, Shengxuan 4, Shengxuan 6, Yangmai 18, Yangfumai 4, Zhenmai 5, Zhenmai 8 and Nannong 0686 were developed by various breeding methods, and all these derivatives maintained its excellent traits such as high and stable yield, moderate resistance to FHB, and resistance to WSSMV. Therefore, it was concluded that Ningmai 9 was an elite parent with high general combining ability, and it had important value for developing the new wheat cultivars with high-yielding, better quality and disease resistance.

宁麦9号是高产稳产、适应性广、中抗赤霉病、高抗梭条花叶病的优质弱筋小麦品种,由该品种衍生的10个品种已成为或即将成为长江中下游麦区的主推品种。为探讨宁麦9号作为亲本在小麦育种上的利用价值,本文分析了该品种的高产生理基础,产量、品质和抗病性状的遗传以及其衍生品种的主要特点。结果表明,宁麦9号光合优势明显,后期叶片不易早衰,水分利用率高、抗旱性强,其高产优势表现为成穗数和穗粒数多。遗传分析表明,该品种穗粒数、收获指数、蛋白质含量、碱水保持力以及抗病性等性状的配合力高,易于传递给后代。以宁麦9号为亲本,通过不同育种方法,育种工作者先后育成了宁麦13、宁麦14、宁麦16、生选4号、生选6号、扬麦18、扬辐麦4号、镇麦5号、镇麦8号、南农0686等10个小麦新品种,这些衍生品种都保持了宁麦9号高产稳产、中抗赤霉病、抗梭条花叶病等优良特性。因此,认为:宁麦9号是一个一般配合力较高的优良亲本,对选育高产、优质、抗病小麦新品种有重要利用价值。

Genetic diversity among 5029 accessions representing a proposed Chinese wheat core collection was analyzed using 78 pairs of fluorescent microsatellite (SSR) primers mapped to 21 chromosomes. A stepwise hierarchical sampling strategy with priority based on 4×105 SSR data-points was used to construct a core collection from the 23090 initial collections. The core collection consisted of 1160 accessions, including 762 landraces, 348 modern varieties and 50 introduced varieties. The core ac-counts for 23.1% of the 5029 candidate core accessions and 5% of the 23090 initial collections, but retains 94.9% of alleles from the candidate collections and captures 91.5% of the genetic variation in the initial collections. These data indicate that it is possible to maintain genetic diversity in a core col-lection while retaining fewer accessions than the accepted standard, i.e., 10% of the initial collections captured more than 70% of their genetic diversity. Estimated genetic representation of the core con-structed by preferred sampling (91.5%) is much higher than that by random sampling (79.8%). Both mean genetic richness and genetic diversity indices of the landraces were higher than those of the modern varieties in the core. Structure and principal coordinate analysis revealed that the landraces and the modern varieties were two relatively independent subpopulations. Strong genetic differentia-tion associated with ecological environments has occurred in the landraces, but was relatively weak in the modern cultivars. In addition, a mini-core collection was constructed, which consisted of 231 ac-cessions with an estimated 70% representation of the genetic variation from the initial collections. The mini-core has been distributed to various research and breeding institutes for detailed phenotyping and breeding of genetic introgression lines.

Wheat landrace Yanda 1817 is one of the ‘core parental’ breeding lines for North China Winter Wheat Breeding Program during 1950–1960. The derivatives of cross Triumph/Yanda 1817 have been widely planted in the area and, thereafter, used as parental lines to make further crosses for new varieties development. In this study, the genetic contributions of core parental lines Yanda 1817 and Triumph to their derivative cultivars were analyzed using 175 polymorphic SSR markers randomly distributed on the 21 chromosomes of wheat genome with an average of 8.3 markers per chromosome. The results indicated that Triumph (43.6%) contributed more genetic components than Yanda 1817 (26.8%) to their derivatives on the whole genome level. On the A, B and D subgenome levels, triumph had the contribution ratio of 46.1%, 39.1% and 44.0%, While Yanda 1817 only had the contribution ratio of 25.9%, 25.7% and 26.4% to their derivatives, respectively. It revealed that exogenous germplasm played an important role in the improvement of wheat varieties in the North China Winter Wheat Breeding Program. As for single chromosomes, 20.0% (1A) to 63.3% (7A) of Triumph alleles and 7.5% (2A) to 44.2% (7D) of Yanda 1817 alleles could be detected on the derivative cultivars. Seven Yanda 1817 genomic (haplotypic) regions, Xwmc11-3A–Xcfa2262, Xbarc1073-7B–Xwmc475, Xgwm357-1AL–Xwmc312, Xbarc305-7DS–Xwmc506, Xgwm165-4AS–Xgwm610, Xwmc419-1B–Xwmc134, and Xcfd56-2D–Xbarc228, and eight Triumph genomic (haplotypic) regions, Xwmc105-6BS–Xwmc397, Xgdm72-3D–Xgdm8, Xgdm5-2DS–Xgwm455, Xbarc121-7AL–Xgwm332, Xgwm174-5DL–Xwmc161, Xgwm499-5BL–Xbarc308, Xbarc141-5A–Xgwm291, and Xgwm66-4BL–Xgwm251, were found to be significantly important in the Triumph/Yanda 1817 derivative cultivars. Genomic (haplotypic) regions Xwmc11-3A–Xcfa2262 derived from Yanda 1817 and Xwmc105-6BS–Xwmc397 derived from Triumph had the contribution ratio of 77.5% and 71.3%, respectively to the derivative cultivars of Triumph/Yanda 1817, indicating they are important targets for selection in breeding program. Agronomic important genes and QTLs relevant to yield, disease resistance, tolerance to abiotic stresses and adaptation to diversified environments located on these genomic (haplotypic) regions are important targets for new varieties development in the North China Winter Wheat Breeding Program.

小麦地方品种燕大1817是我国小麦育种骨干亲本之一，胜利麦/燕大1817杂交组合是北部冬麦区小麦品种遗传改良的基础组合。利用随机分布于小麦全基因组21条染色体上的175对在胜利麦和燕大1817间具有多态性的SSR标记(每条染色体平均8.3对)分析了燕大1817和胜利麦对其38份后代衍生品种的遗传贡献率。结果表明，在全基因组水平上，燕大1817对其后代衍生品种贡献率为26.8%，胜利麦对其后代衍生品种贡献率为43.6%；在部分同源群水平上，燕大1817对其后代衍生品种A、B和D基因组的贡献率分别为25.9%、25.7和26.4%，胜利麦对其后代衍生品种A、B和D基因组的贡献率分别为46.1%、39.1%和44.0%。说明引进种质对我国北部冬麦区小麦品种遗传改良起了重要作用。在染色体水平上，胜利麦对其后代衍生品种的21条染色体贡献率在20.0%~63.3%间，其中对1A染色体贡献率仅有20.0%，对7A染色体贡献率高达63.3%。骨干亲本燕大1817对其后代衍生品种的21条染色体贡献率在7.5%~44.2%间，其中对2A染色体贡献率仅有7.5%，对7D染色体贡献率可达44.2%。骨干亲本燕大1817对后代衍生品种贡献率较高的基因组(单元型)区段有7个，分别是3A上的Xwmc11–Xcfa2262、7B上的Xbarc1073–Xwmc475、1AL上的Xgwm357–Xwmc312、7DS上的Xbarc305–Xwmc506、4AS上的 Xgwm165–Xgwm610、1B上的Xwmc419–Xwmc134和2D上的Xcfd56–Xbarc228，其中，3A染色体上的Xwmc11–Xcfa2262区段对衍生品种贡献率高达77.5%。而胜利麦对后代衍生品种贡献率较高的基因组(单元型)区段有8个，分别是6BS上的Xwmc105－Xwmc397、3D上的Xgdm72–Xgdm8、2DS上的Xgdm5–Xgwm455、7AL上的Xbarc121–Xgwm332、5DL上的Xgwm174–Xwmc161、5BL上的 Xgwm499–Xbarc308、5A上的Xbarc141–Xgwm291和4BL上的Xgwm66–Xgwm251，其中6BS上的Xwmc105–Xwmc397区段对衍生品种的贡献率最高，达71.3%。这些基因组(单元型)区段上存在许多与产量、抗病、抗逆和适应性等重要农艺性状相关的基因和QTL，对北部冬麦区小麦品种遗传改良可能起了重要作用。

Abstract

Wheat (Triticum aestivum L.) cultivar Bima 4 is one of the most important milestone parents in China. The objectives of this study were to reveal the genetic structure of Bima 4 and the transmission of its specific loci in descendents using molecular markers. A total of 1239 simple sequence repeat (SSR), expressed sequence tag derived SSR (EST-SSR), and sequence tagged site (STS) markers covering the whole genome of wheat were screened with the 4 parents of the first generation of Bima 4 progenies, i.e., Bima 4, Early Piemium, Jubileina 2, and Ckopocneka JI-1. Thirty-three markers were effective to trace the specific loci of Bima 4 in the progenies. Seventy-six derivatives of Bima 4 were genotyped using these markers. Among them, 32 markers except for Xgwm577 could amplify the specific bands of Bima 4 in the first and the second generations derived from Bima 4. Eight and ten loci showed the transmission percentage larger than 50% in the first and the second generations, respectively. In the third and the fourth generations, 29 and 20 specific markers were observed. In these markers, 8 and 4 loci had the transmission rate higher than 50%, respectively. Among the specific loci, Xgwm261, Xedm80, SWES222, and CFE223 possessed inheritable frequency higher than 50% in all of the 4 generations. Furthermore, 18 loci of Bima 4 were detected in the progenies with genetic contribution ratio higher than 25%. This indicates that some desirable traits, such as yield, grain quality, disease resistance, and adaptability might be associated with these loci or the nearby chromosome regions in Bima 4, which were intensively selected in breeding programs. The important loci detected in this study provide information for understanding the genetic basis of Bima 4 as a milestone parent in wheat breeding.

摘 要

为探讨小麦骨干亲本碧蚂4号的遗传构成及其特异位点在衍生后代中的传递特点, 利用覆盖小麦全基因组的1 239个SSR、EST-SSR和STS标记对碧蚂4号子一代衍生品种(系)的4个亲本进行标记筛选, 获得33个特异标记可用于76份碧蚂4号衍生材料的分析。在子一代和子二代材料中, 除标记Xgwm577外的32个标记均能扩增出碧蚂4号特异带, 且分别有8个和10个标记位点的传递频率大于50%; 在子三代和子四代材料中能扩增出碧蚂4号特异带的标记分别有29个和20个, 传递频率大于50%的标记位点分别有8个和4个; Xgwm261、Xedm80、SWES222和CFE223在4个世代中的传递频率都保持在50%以上; 有18个标记位点对衍生品种(系)的遗传贡献率大于25%; 推测这些基因组位点及其附近的染色体区域可能是被育种家强烈选择的部分, 碧蚂4号含有一些特殊的与重要农艺性状相关的基因组位点/区段, 可能是其成为骨干亲本的遗传基础。

The genetic mechanism of thousand-grain weight (TGW) and number of kernels per spike (NKS) were studied by a 7×7 complete diallel crosses (Griffing's method II) using seven wheat parents with diverse TGW and NKS during 2009-2010 growing season. The results showed that Yangmai 11 and Ningmai 9 had the best general combining ability for TGW and NKS, respectively, and Ningmai 9 had more dominant genes controlling NKS. The inheritance of TGW fit for the additive-dominance-epistasis model, and the inheritance of NKS was in agreement with the additive-dominance model. The NKS was controlled by both additive and dominant genetic effects, and the additive effect was much more important than the dominant effect. The degree of dominance was partial dominance. The alleles increasing NKS were dominant, and the frequency distribution of alleles increasing or reducing NKS was asymmetrical among 7 parents. Narrow sense heritability of NKS was higher, indicating that selection of NKS in early generation was effective. The genetic improvement on TGW and NKS was also discussed in the paper.

利用千粒重和每穗粒数有一定差异的7个冬小麦品种为亲本,按Griffing双列杂交法Ⅱ配制21个杂交组合,研究了小麦2个产量构成因素——千粒重和每穗粒数的遗传。结果表明,扬麦11千粒重和宁麦9号每穗粒数的一般配合力最好,且宁麦9号具有控制每穗粒数较多的显性基因。千粒重的遗传符合加性-显性-上位性模型。每穗粒数的遗传符合加性-显性模型,以加性效应为主,显性程度为部分显性。控制每穗粒数的增效等位基因为显性,亲本中增减效等位基因频率分布不对称。每穗粒数的狭义遗传力较高,早代选择有效。还对小麦粒重和每穗粒数的遗传改良进行了探讨。