小麦育种研究论文

戴松恩从20年代中期即开始进入我国的作物遗传育种研究领域，是我国从事这方面工作较早的学者之一。他早年参与育成和推广了“金大2905”、“金大26”等小麦品种。30年代，他利用来自中国、苏联、美国的小麦品种进行杂交，对其性状遗传规律做了研究。当时，这种相当规模的遗传研究国内还没有过。他通过对六个普通小麦品种的春冬性及穗部、叶片等十多个性状的遗传分析，明确了单性状的遗传规律以及它们之间的连锁遗传关系，以博士论文形式发表了题为《中俄美小麦品种杂交之遗传研究》的报告（中文摘要发表于《农报》1937年7月）。1938年，他在贵阳对烟草、玉米和油菜生产进行了深入考察，发现贵阳地区适宜发展烟草种植。在他的努力下引进了美国烟草品种。经过三年试验，于1940年第一次在贵阳地区种植了经他引种筛选出来的烟草新品种，并示范推广了育苗、移栽、管理、采收以至烤烟技术。这些工作为后来贵州烟草事业发展奠定了坚实的基础。戴松恩还针对当时有人提出要大量引入美国双杂交玉米种子的问题，进行了三年引种试验，发现美国双杂交玉米种并不比当地的最优品种好，有的甚至更差。他在《美国杂交玉米在我国的利用问题》（《农报》1939年）一文中明确指出：直接利用美国双杂交玉米并不能增产，只有利用它的自交系和国内材料才能找出适应我国情况的高产杂交玉米来。同一时期，他还为当地的油菜育种做了不少基础研究工作，诸如连续自交对不同类型油菜品种的生长发育和结实性的影响等，为制定合理的育种方案提供了科学依据。赤霉病是长江下游地区小麦生育后期最易流行的严重病害。有些国外专家曾散布在严格接种的条件下，小麦品种都要感染赤霉病，抗病育种谈何容易的悲观论点。戴松恩等怀着试试看的心情，对已搜集到的小麦品种材料进行了连续四年的抗病性鉴定试验。1941年，他发表了《小麦赤霉病抗病性研究》（《农报》1941年），指出在严格接种条件下中国小麦品种中有对小麦赤霉病表现抵抗的材料，并以云南“牟定火麦”为例，论证了选育抗病品种的可能性。这一发现，对发展我国小麦抗赤霉病育种工作是一个很好的启发。50年代初，我国学术界出现了“米丘林遗传学”和“摩尔根遗传学”两个学派的争论。戴松恩为了验证李森科“种内无竞争”的学说，和育种中搞“品种内杂交”以改良种性措施的真伪进行了四年的系统研究，结果得不出上述结论；虽然提出了对“米丘林遗传学”中“嫁接杂种”，“获得性遗传”的不同看法，限于当时“一面倒”的形势，未公开发表。为了弥补我国在小麦育种基础理论及方法上与国外的差距，从1978年起戴松恩主持了“小麦非整倍体研究”。这是为小麦定向育种提供理论根据的基础研究，是利用非整倍体材料和相应的分析方法，测定基因位置及连锁关系，通过染色体附加、代换和易位技术，达到有计划、有步骤地创造麦类新品种的目的。这项技术在当时我国比美、英、加等国家落后。1980年，他主持召开了“全国小麦非整倍体研究讨论会”，并发表了《为什么研究小麦非整倍体》及《小麦非整倍体》（经典著作的译文）等文章，积极推动了这项研究工作的发展。他强调指出，小麦非整倍体研究在形态形状、抗病虫性、抗逆性、品质性状和其他数量性状的基因分析或定位等方面很有意义，并可直接应用于小麦育种，为农业生产做出贡献。他提出了在小麦品种间杂交中，利用ph基因创造出更多优良变异的设想。在他的指导下，他的助手和研究生已取得了可喜的成果，并进行了各种变异类型的细胞遗传学研究，为开创小麦育种的新途径进行了有益的尝试。他担任中国农业科学院研究生院副院长时，对教学指导认真负责，一丝不苟，并且亲自带研究生，也没有中断过研究工作。他还对如何提高研究生培养水平提出了许多新的建议。1982年我国研究生学位制度恢复没有几年时间，他多次建议本科生大学毕业工作2年后才准报考研究生，建议从1984年招收在职研究生，加速培养他们成为能够独立工作，富有开拓精神的科研人才。同时，他积极倡导对在职人员进行培训，不断提高业务水平。他还为中国农业科学院研究生教育的发展，争取必要的物质条件，做了大量工作。

利用生物技术向小麦导入冰草优异基因的研究 摘 要 小麦是世界上种植面积最大和最重要的粮食作物。利用生物技术向栽培作物转移向外源优异基因来拓宽小麦育种的遗传基础，是现代作物遗传育种学科中的一个非常重要的研究领域。 栽培小麦(Triticum aestivum L., 2n=4x-42, AABBDD)与冰草属(Agropyron Gaertn., P genome )(这儿所说的冰草属是现代小麦族植物分类学上的概念，而非传统的广义冰草属概念，即与一些小麦遗传育种学家将长穗偃麦草(Elytrigia elongata)和中间偃麦草(Elytrigia intermedia)等偃麦草属种也称为冰草的传统概念截然不同)植物间的杂交，可追溯到本世纪30年代(White, 1940; Smith, 1942; Dewey , 1984), 但直到90年代一些学者才先后报道了小麦与冰草属植物间的成功杂交(李立会等， 1990， 1995；Li & Dong, 1991; Chen et al., 1990; Limin & Fowler, 1990; Ahmad & Comeau , 1992; Jauhar, 1992)。 尽管这儿所列出的国外一些科学家也曾获得了小麦与冰草属植物间的杂种，但由于外源种选择的盲然性，即对要从冰草属植物向小麦转移哪些基因不明确(Chen et al., 1990; Jauhar, 1992), 或杂种F1的高度不育性(Ahmad & Comear, 1992), 或要转移的目标基因难以在小麦背景下表达(Limin & Fowler, 1990 )等原因，未见进一步的报道，而是基本上放弃了该领域的研究工作(私人通信，1997)。 在本项研究工作中，我们以普通小麦品种Fukuho (春性，具3对可杂交性基因，农艺性状良好，原产于日本)为母本，以分别采自新疆和内蒙古的3份冰草(Agropyron cristatum Gaertn., 2n=4x=28, PPPP)为父本进行杂交，并对杂种后代进行了研究。主要结果包括： 1、科学选择远缘杂交亲本，为杂交和外源优异基因转移的成功奠定了坚实的基础。在选择外源供体种的过程中，本项研究首先由中国农业科学院作物品种资源研究所和植物保护研究所、澳大利亚Division of Plant Industry, CSIRO, 加拿大Cytogenetics Section, Ottawa Research Station, Agriculture Canada 等单位对上千份小麦野生近缘植物的农艺性状、抗逆性和抗病性进行了联合鉴定，然后根据综合鉴定结果才精选出本项研究所利用的3份冰草－最佳外源供体种。因为这3份冰草不仅具有其它外源种难以比拟的众多优异基因（性状），包括小麦超高产育种所需的合理株型结构(株高小于60cm且穗下茎长度约占株高的2/3、有效分蘖>50、叶片窄短上挺)、大穗多粒（每穗结实在150粒以上）、黑粒且蛋白质含量极高、极强的抗旱和抗寒性、适度的耐盐性、对三种锈病、白粉病和黄矮病免疫、高抗赤霉病等，而且更为重要的是上述优异基因都是当前小麦育种迫切需要的。 2、利用现代远缘杂交方法和幼胚拯救技术，在国际上首次获得了具部分自交可育性的普通小麦与冰草间的杂种，并发现以不同来源的冰草为父本，不仅杂交结实率不同，而且杂种F1的表现型亦不同。这一结果，一方面突破了前人(Dewey, 1984)所认为的“冰草属P染色体组在小麦族中具有独立的遗传地位，与小麦之间不可能杂交”的论断；另一方面杂种F1具部分自交可育性，为实现外源基因的成功转移 奠定了坚实的物质基础。 3、以杂种F1幼穗为外植体，通过诱导愈伤组织产生体细胞无性系变异，首次发现杂种F1在无染色体数量变异情况下，其自交可育性或从无到有(0Õ 0.032%),或显著提高(10倍)。这一发现之所以重要，是因为它向人们展示了通过这一技术有可能在杂种F1就实现外源基因转移的美好前景。 4、通过精细分析，首次阐明了一些遗传学机理：一是杂种F1自交可育性是由于2条P染色体含有控制减数分裂过程中染色体分离的基因，从而能够形成有功能的近等2n或未减数配子；二是另外1条P染色体上具有抑制小麦Ph基因的遗传因子，能够诱发冰草P染色体组和小麦A、B、D染色体组间的染色体相互配对；三是证实了通过染色体间的自发易位可实现小麦－冰草间的基因交流。这些发现，一方面彻底突破了国际权威所认为的“小麦－冰草间不可能进行基因交流”的论断，另一方面为更加有目的、更加高效率地转移冰草优异基因提供了重要的理论指导。 5、利用回交、选择和形态学、细胞学、等位酶以及基因组原位杂交检测等综合技术，首次育成了11个遗传稳定的小麦－冰草异源二体附加系，并提出了有效产生异源二体附加系（列）的可行做法。异源二体附加系的产生，是研究每条P染色体上的基因在小麦背景下的遗传效应及其有效利用的重要工具。 6、首次创造了一批携带冰草优异基因、遗传稳定(2n=42, 21II ,异源易位系或代换系)且能为育种和生产利用的新种质。其普遍的特点是：有效分蘖多(15~82穗/株)；株高70～95cm且穗下茎约占株高的1/2；旗叶上挺；大穗(55～112粒/穗)；籽粒外观白色或黑色、蛋白质含量高(17.1~20.7%); 千粒重>38g; 综合抗病性（白粉病、条锈病、黄矮病和赤霉病)、抗寒性和抗旱性良好，特别是一些新种质具超高产潜力(理论产量高于600 kg/亩)。目前，这批新种质已为我国小麦主产区的9省15家育种单位利用，其中在陕西、山西有5个新种质正参加产量比较试验。 7、对获得的遗传稳定(2n=42, 21II ,异源易位系)的黑色籽粒和对白粉病免疫新种质中的黑色籽粒基因和抗白粉病基因(均来自冰草)进行了初步遗传分析，证明二者皆为显性单基因遗传。关键词：普通小麦(Triticum aestivum, L., 2n=6x=42, AABBDD); 冰草(Agropyron cristatum Gaertn., 2n=4x=28, PPPP)；属间杂种；自交可育性；异源二体附加系；遗传分析；新种质Introduction of Desirable Genes from Agropyron cristatum (L.) Gaertn. to Triticum aestivum L. Using BiotechnologyDoctoral student : Li-Hui LiSupervisor: Professor Yu-Shen Dong (Institute of Crop Germplasm Resources, Chinese Academy of Agriculture Sciences, Beijing, 100081)AbstractAs in most other crops, the genetic variation of cultivated wheat has been greatly eroded under modern agricultural systems. Genetic erosion not only limits the further improvement of yield and quality but also makes wheat increasingly vulnerable to biological and environmental stresses. A large amount of genetic variation exists in the wild relatives of cultivated wheat. The introduction of genetic variation from alien species has been a valuable method for increasing the amount of genetic diversity available to wheat breeders.In this experiment, intergeneric hybrids of Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) with three accessions of tetraploid A. cristatum (2n=4x=28, PPPP) were synthesized through immature embryo rescued in artificial medium. These hybrids can be used to: (1) transfer the desirable traits from A. cristatum into common wheat; (2) identify the effects of the P genome on self-fertility in intergeneric hybrids; and (3) produce disomic addition lines of wheat-A. cristatum. Through study of the intergeneric hybrids and their derivatives, the following results were obtained:1. A. cristatum may be one of the best potential alien donors in the Triticeae for wheat improvement. Agropyron Gaertn. is a small genus of no more than ten species, which constitute what is known as the “crested wheatgrass complex” with the P genome, in accordance with the terminology of many modern botanists. A. cristatum (L.) Gaertn. is the type species of this genus. All species of the genus are very valuable; they are cultivated as predominantly pasture-fodder plants, distinguished by their high level of drought and cold tolerance; some species have be successfully used for fixing drifting sands. In addition, A. cristatum has also been found to possess the other desirable traits that are potentially valuable for wheat improvement through evaluation of all Triticeae collections from the northern part of China; these include shorter stem (usually less than 60 cm), more tillers and florets, immunity to wheat diseases such as rusts, powdery mildew, and barley yellow dwarf virus (BYDV) as well as resistance to wheat scab. 2. In the three hybridization combinations, seed set (0.22%~0.63%) and plant development were different. Each one plant obtained from Fukuho with A. cristatum accession No. Z540 and Z602 respective developed poorly. The former died before heading. Although the later produced two spikes, neither selfed nor backcross seed was obtained from these two spikes. The two plants obtained from the Fukuho×A. cristatum Z559 showed vigorous tillering. This result indicated that the three accessions of A. cristatum used in this experiment are different in crossability with the Fukuho. The root-tips of all hybrid seedlings were observed, and revealed that somatic chromosome number of each was 2n=35 as expected.3. A self-fertile intergeneric hybrids between Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) and tetraploid A. cristatum (2n=4x=28, PPPP) were obtained for the first time.In contrast with the reports that either no BC1 derivatives from wheat-Agropyron hybrids was obtained or BC1 derivatives obtained were very difficult, in the Fukuho×A. cristatum Z559 hybrids, however, they not only had a high seed set (15.1%) of backcrossing with common wheat, but also were partially self-fertile. The mean configurations at meiotic metaphase I of the hybrids were 24.47 I + 4.32 rod Ⅱ + 0.71 ring Ⅱ + 0.14 Ⅲ + 0.01 Ⅳ. Some of bivalents per cell were clearly heteromorphic on the basis of various chromosome size, indicating that these bivalents were heterogenetic pairing. At anaphase I, chromosome separation was mainly the most (16~30 chromosomes) of 35 chromosomes to assemble at one pole, resulting in that the bigger daughter cells receiving most of 35 chromosomes might develop the functional gametes.4. In order to induce somaclonal variation, the immature inflorescences of the hybrids between Triticum aestivum cv Fukuho and A. cristatum Z559 were cultured. Although the regenerants did not exhibit variation in chromosome number, they did show a higher degree of meiotic instability than the initial hybrids. Especially, the selfed seed set could be increased greatly in the regenerated plants, being from 0.034% to 0.33%. As a result, a total of 61 selfed seeds were obtained. Obtaining of so more selfed seeds from the Fukuho×A. cristatum Z559 is rare in the intergeneric hybrids involving wheat, and makes a substantial foundation for transferring the desirable genes from A. cristatum into common wheat. 5. Using methods such as morphology, cytology, isozymes and genomic in situ hybridization, the selfed and backcross derivatives were analysed. The results showed that all plants with the alien characters carried the genetic materials of the P genome. Meanwhile, a total of 11 disomic alien addtion lines were obtained. 6. After all cytological data obtained from this experiment were summed up and analysed, some conclusions could be obtained. They were: (1) the A. cristatum Z559 used in this experiment carried a genetic system suppressing Ph activity, and this genetic system might be mainly involved one of the P genome; (2) the P genome contained genes controlling chromosomes segregation at meiotic anaphase, and the genes might be mainly involved two of the P chromosomes; and (3) the spontaneous wheat-A. cristatum translocations can occur in the selfed and backcross derivatives.7. In this experiment, the other very important result is that some new germplasm with the desirable alien genes were obtained. They showed more effective tillerings (15-82 spikes per plant), plant height ranged from 70 to 95 cm, 55-112 grains per spike, a higher content of protein (17.1-20.7%), resistance to wheat diseases such as powdery mildew, stripe rust, BYDV and wheat scab, and tolerance to drought and cold. So far, all new germplasm obtained from this experiment have been utilized by the 15 institutions for wheat breeding in China.8. The new germplasm with black-grain in color and immunity to powdery mildew were analyzed. Genetic analysis revealed that these two characters were from A. cristatum Z559 and were controlled by a dominant gene respectively. Key Words: Triticum aestivum L., Agropyron cristatum, Intergeneric hybrids, Self-fertility, Alien addition and translocation lines, Genetic analysis.