CIMMYT牧草DNA导入普通玉米后植物学形态变异研究

本研究以CIMMYT牧草和4个普通玉米自交系为遗传交配材料,比较研究了CIMMYT牧草和4个杂交（回交）后代的植物学形态特征及其与普通玉米的差异。结果表明,CIMMYT牧草能将其生长繁茂、分蘖力强、生物产量高的特性遗传给杂交后代,并有较强的世代传递能力;该牧草幼苗、植株及其生长习性、花器官、种子特征等与普通玉米差异明显,其与普通玉米的杂交后代基本保持了它的生长发育特性,但花器官和种子特征更偏向于普通玉米;回交后代除保持了一定的分蘖特性、明显的多穗和返祖现象外,其余特征特性与普通玉米基本没有区别。     

抗旱型玉米苗期根系形态性状的遗传分析

为了进一步揭示玉米苗期根系性状的遗传特性,用来改良材料的抗旱性,本研究以旱敏型材料‘WN897’、抗旱型材料‘Wu109’及二者通过杂交和回交获得的F1、B1、B2和F2为材料,利用主基因+多基因混合遗传模型多世代联合分析方法分析干旱胁迫与正常条件下主根长、侧根数、根冠比和根鲜重的遗传特性。结果表明,在干旱胁迫与正常条件下,侧根数的遗传率均高,而主根长、根冠比及根鲜重的遗传率均较低,根冠比的遗传率在干旱胁迫下明显低于正常条件,根鲜重的遗传率在干旱胁迫下明显高于正常条件。因此,侧根数可以通过单交的方法进行改良,在低世代材料中就可进行有效选择,主根长可以通过复交或多代轮交进行改良;而对于根冠比和根鲜重,鉴于二者均在B2群体中有着较高的遗传率,可以通过多代回交的方法对这两个性状进行改良,在回交后代中进行有效选择。     

不同生态类型厚皮甜瓜雌雄异花同株系的转育

为培育厚皮甜瓜单性花新品系,以雌雄异花同株系和普通两性花系为亲本进行杂交,杂交后代采用三条途径转育单性花近等基因系,通过调查转育各世代及入选品系与不同生态类型材料配制的杂交组合中花性型的遗传分离情况,检测分析雌雄异花同株性状的遗传稳定性。结果表明：Mr分别与Mm,Ym,YF,F—Y配制的4个杂交组合中,F2的花性型分离为：单性花：两性花=3：1;以Mm,Ym为轮回亲本的不同世代,花性型分离为：单性花：两性花=1：1。推测为供试材料间性型的不同仅存在于a位点的基因型差异,由等位基因A控制的单性花性状呈稳定的单显性基因遗传。用不同生态类型的优良育种材料作轮回亲本,采用连续回交、最后自交分离选择,以及杂交后代连续自交分离选择的方式,培育出4个单性花材料。     

水稻早世代稳定特性的遗传研究

422、429、430、942、950、966是由多倍体(四倍体或三倍体)与二倍体杂交得来的早世代稳定水稻品系,利用上述早稳型水稻与普通二倍体水稻杂交,以研究水稻早世代稳定特性在杂交后代的遗传。通过田间观察和分子标记的检测F2,结果发现在大量的杂交组合后代中,只有429×9311杂交组合后代仍具有早世代稳定特性,即早世代稳定特性在该杂交组合中遗传了下来,而其它杂交组合中,早世代稳定特性未能遗传下来,推测早世代稳定特性的遗传可能和杂交双亲均有关。     

爆裂玉米膨爆特性的遗传及杂交种选育研究进展

综述了爆裂玉米膨爆特性的遗传及其与穗粒性状的相关性、爆裂玉米的育种方法等方面的国内外研究进展。爆裂玉米的膨爆特性是由多基因控制的数量性状，与籽粒产量及大多数穗粒性状呈显著负相关。通过不同爆裂玉米间相互杂交及其与普通玉米杂交、回交或长期的轮回选择，可有效地聚集分散在不同材料、不同个体中的优良性状和有利基因，显著提高育种效果。     

八倍体小偃麦与普通小麦杂种自交和回交后代染色体和性状分离的研究

以八倍体小偃麦小偃６９３和普通小麦烟农１５的六个不同杂种世代为材料，研究了自交和顺交对杂种后代染色体和性状分离的不同影响。结果表明，随自交和以烟农１５为轮回亲本回交世代的增加，染色体数目逐渐减少，但回交比自交能使后代中偃麦草染色体丢失更快；回交后代ＰＭＣＭＩ染色体构型较为简单，平均交叉结数减少，回交次数过多不利于偃麦草与普通小麦染色体发生遗传重组；自交和回交世代中小偃麦类型、中间类型和小麦类型出现     

小麦—天蓝偃麦草—羊草三属杂种回交世代中几个主要性状的遗传表现

采用普通小麦与天蓝偃麦草属间远缘杂种后代八倍体小偃麦（ＡＡＢＢＤＤＥＥ）为母本，与羊草（滨麦草属）杂交，获得三属杂种后，再用普通小麦回交２￣３次，并对三属杂种以及回交世代中几个主要性状的遗传表现进行了研究，结果表明：①三属杂种Ｆ１的不育性，采用普通小麦通过回交可得到克服，并且随着回交次数的增加，结实率逐步提高；②回交后代有明显的超矮亲遗传现象；③天蓝偃麦草与羊草的抗病、大穗、多花多实等性状可直接传     

基于SNP芯片划分CIMMYT和广西玉米自交系杂种优势群

CIMMYT玉米自交系在广西具有较好的适应性，目前利用CIMMYT和广西玉米自交系杂交已成功选育出许多适合广西种植的玉米新品种。为了解CIMMYT和广西玉米自交系间的杂种优势关系，本研究以20份CIMMYT自交系和169份广西自交系为供试材料，以5份中国骨干自交系和4份广西骨干自交系作为参照系，利用10K玉米SNP芯片进行全基因组扫描，开展遗传相似性、系统进化树和主成分分析，划分参试材料的杂种优势群。研究结果表明，189份玉米自交系绝大多数杂合率均小于10%，纯合度较高。CIMMYT自交系相互间遗传相似性较高，与广西玉米自交系间遗传相似度较低。进化树和主成分分析将189份自交系分为PB群、SPT群、‘桂单162-0810’母本群、‘桂单162’父本群、‘桂单0810’父本群和其他类群，其中大部分CIMMYT玉米自交系属于SPT群，大部分广西玉米自交系属于‘桂单162-0810’母本群、‘桂单0810’父本群和其他类群。可见，CIMMYT与广西玉米自交系间遗传差异较大，大多属于不同杂种优势群，两类自交系进行杂交能够较大概率获得优良玉米品种。     

玉米与玉米近缘种可杂交性研究

本文对玉米与其近缘种及它们的杂交或回交后代的可杂交性进行了研究。结果表明，玉米近缘种的多数材料都能与玉米杂交结实，它们的杂种F1均表现出强的杂种优势和光敏反应；远缘杂交亲和性的母本效应较大，且与物种间遗传距离直接相关。此外，还对玉米近缘材料在玉米遗传育种中的应用进行了探讨。     

偏凸-柱穗山羊草双二倍体与普通小麦不同杂种世代的染色体及性状分离特点

为探讨偏凸山羊草－柱穗山羊草双二倍体SDAU18在小麦遗传改良中的利用价值,以SDAU18和普通小麦品种烟农15及其9个杂种世代为材料,分析不同自交和回交世代染色体和性状分离的特点。结果表明,随自交和以烟农15为轮回亲本回交世代的增加,染色体数目逐渐减少,回交比自交能使后代的染色体数目更快趋近普通小麦的42条,至F₅和BC₃F₁代,染色体数目为42的植株已分别达93.9%和92.0%。与自交世代相比,回交后代减数第一分裂中期的花粉母细胞的染色体构型较为简单,回交次数过多不利于外源染色体与普通小麦染色体发生重组,一般应以回交2~3次为宜;随自交和回交世代的增进,杂种的育性提高,至F₃和BC₂F₁代育性基本稳定。在不同杂种世代可分离出具有矮秆、大穗、大粒、对白粉病、条锈病免疫或高抗及外观品质优良的变异类型,以F₃和BC₁F₁代的变异类型最丰富。     

Production of an interspecific hybrid between Texas and Argentine bluegrass

Texas and Argentine bluegrass are both dioecious Poa species with distinct morphological characteristics. Argentine bluegrass has a bunch-type growth habit, fine upright leaves and does not produce rhizomes. Texas bluegrass spreads by rhizomes and has wider, longer leaves. In an effort to produce novel germplasm with forage or turf potential, experiments were conducted to determine whether hybrid seed could be produced. Crosses were made using pollen from an Argentine male to fertilize two Texas female plants. Parents were induced to flower in the greenhouse by extending the photoperiod to 18 h with 400 W high-pressure sodium lamps from late December to April. The two crosses produced >200 seeds each. Hybrid seedlings segregated for traits from both parents. A sorghum-derived SSR marker confirmed the hybrid nature of a group of seedlings. Seeds harvested from F1 plants using Texas or Texas × Argentine pollen lost the undesirable cottony characteristic of Texas bluegrass. Evaluations for forage and turf potential of hybrid and later generation seed are planned.     

大红花蝴蝶兰杂交后代观赏性状分离规律研究

[目的]为研究蝴蝶兰观赏性状遗传规律,优化杂交亲本,更加高效的培育高品质的蝴蝶兰新品种。[方法]以5份大红花蝴蝶兰为材料,设计了3组正反交杂交组合,并对杂种后代花底色、花径、花朵数、花梗高度、植株冠幅等主要观赏性状进行了观测分析。[结果]结果表明,3个组合正反交杂种后代,花底色、花朵数、花梗高度等性状杂种优势明显,在花色上出现了亲本没有的花斑变化,正反交分离表现明显不同,深紫红色大红花作为母本时,获得深色杂种后代的几率更高;3个杂交组合正反交杂种后代花径分离表现不尽相同,‘T’和‘R’组合正反交杂种后代花径则表现超亲优势,而‘133’和‘62’,‘J’和‘62’正反交则表现出一定程度的衰退现象,当母本花径较大时,杂种后代花径总体较大,但获得超亲花径的比例低;3个组合正反交植株冠幅均表现一定程度的衰退现象。[结论]该研究结果初步阐明大红花杂种后代主要观赏性状的分离表现,为蝴蝶兰育种亲本的选配和新品种选育提供理论依据。     

玉米杂交种及其亲本自交系的生化指纹鉴定

本试验以浙单9号等五个玉米杂交组合及其亲本自交系为材料,进行种子盐溶蛋白聚丙烯酰胺凝胶电泳等多种电泳鉴定方法的研究,以揭示玉米杂交种及其亲本自交系的“生化指纹”(biochenucal fingerprint),以及筛选出适合于玉米杂交种及其亲本自交系真实性和纯度鉴定的方法。结果表明,各供试玉米杂交种及其亲本自交系都具有相应的、唯一的种子盐溶蛋白聚丙烯酰胺凝胶电泳所显现的生化指纹。对于有些组合。玉米芽鞘和叶片绿色组织过氧化物酶同工酶电泳图谱存在阴极第4、第5酶带差异,因这两条酶带的差异稳定,并且重现性好,故能用过氧化物酶同工酶技术对其进行有效地鉴定。上述两种方法,尤其是前者,因技术要求不高,费用低,快速及重现性好等特点,能满足我国目前种子检验室日常玉米品种纯度快速测定工作的要求,具育良好的应用前景。     

Accelerated development of quality protein maize hybrid through marker‐assisted introgression of opaque‐2 allele

Vivek Maize Hybrid 9‐ a popular single‐cross hybrid developed by crossing CM 212 and CM 145 was released for commercial cultivation in India. The parental lines, being deficient in lysine and tryptophan, were selected for introgression of opaque‐2 allele using CML 180 and CML 170 as donor lines through marker‐assisted backcross breeding. The opaque‐2 homozygous recessive genotypes with >90% recovery of the recurrent parent genome were selected in BC₂F_2, and the seeds with <25% opaqueness in BC₂F₃ were forwarded for seed multiplication. Vivek Quality Protein Maize (QPM) 9, the improved QPM hybrid, showed 41% increase in tryptophan and 30% increase in lysine over the original hybrid. The grain yield of the improved hybrid was on par with the original hybrid. The newly improved QPM maize hybrid released in 2008 will help in reducing the protein malnutrition because its biological value is superior over the normal maize hybrids. This short duration QPM maize hybrid has been adopted in several hill states of North Western and North Eastern Himalayan regions.     

Pre- and post-fertilization barriers to backcrossing the interspecific hybrid between Allium fistulosum L. and A. cepa L. with A. cepa

Summary To facilitate the introgression of desirable traits of Allium fistulosum into the genome of A. cepa, several accessions of the hybrid between these species were pollinated with A. cepa as the recurrent parent, and in vitro ovary and ovule culture were performed to obtain an increase in the recovery of backcross progeny. Compared to the results obtained from seed development in planta, the increase in the number of backcross progeny was generally very limited, and in some cases even a decrease was found. Raising the sucrose concentration in the ovary culture medium resulted in a higher frequency of ovules developing back seed coats but this was not followed by an increase in the number of backcross progeny obtained. Pollen tube growth of A. cepa was disturbed in the styles of the interspecific hybrids. Per ovule, frequencies of micropylar penetration exceeded frequencies of backcross progeny only to a limited extent. Hence, it was concluded that in the tested interspecific hybrid accessions the attainable gain in viable backcross progeny by the application of in vitro culture techniques is limited by strong pre-fertilization barriers acting at the level of stylar incongruity.     

白芥和甘蓝型油菜属间杂种后代种子结构比较

白芥具有很多优良的农艺性状,从白芥和甘蓝型油菜属间体细胞杂种后代中筛选出多个具有黄籽或趋向黄籽性状的株系,利用光学显微镜和电子显微镜技术观察它们种子的结构。回交后代种皮解剖结构与甘蓝型油菜相似,而与白芥相差较远。种皮色素主要分布在栅栏层,甘蓝型油菜和部分后代株系中有色素分布,而白芥和部分黄籽后代株系中没有色素分布。栅栏层在甘蓝型油菜中最厚,在白芥中最薄,而后代介于两者之间。回交后代和甘蓝型油菜种皮表面纹饰为网-穴状,白芥为沟槽状或水疱状。胚子叶细胞面积以白芥最小,甘蓝型油菜最大,后代介于两者之间;而蛋白体面积指数以白芥最大,甘蓝型油菜最小,后代介于两者之间。超微结构观察表明,亲本和后代蛋白体均为球状晶体蛋白体,油体有大、小两种,其大小在亲本和后代间有差异。上述结果表明,回交后代株系种子解剖结构与甘蓝型油菜相近,种皮颜色、色泽深浅和栅栏层厚度,以及胚子叶细胞大小、油体和蛋白体等受亲本白芥的影响而发生变化。     

A comparison of methods for hybrid seed production using self-incompatibility in swedes (Brassica napus ssp. napobrassica)

Procedures for producing seed of hybrid swedes using self-incompatibility were examined. Single-cross, double-cross and modified double-cross hybrids were compared in isolation plots using natural pollinators and in polythene tunnels using blow-flies. With good coincidence of flowering and the same flower colour, nearly 100% hybrid seed was produced by natural pollinators with the single-crosses, the double-cross and one of the two modified double-cross hybrids; the other modified double-cross hybrid produced 87%hybrid seed. With poor coincidence of flowering and different flower colours the proportion of hybrids dropped to 61%. Using different flower colours and blow-flies as pollinators in polythene tunnels, higher levels of outcrossing were produced than in isolation plots with natural pollinators; the opposite result was obtained when the same flower colour was used. This revised version was published online in July 2006 with corrections to the Cover Date.