自然四倍体泥鳅雄核发育二倍体染色体组构成研究

为探究鱼类雄核发育新途径及自然四倍体泥鳅所产生的配子染色体组构成,采用自然四倍体泥鳅(4n=100)为父本、二倍体泥鳅(2n=50)为母本进行杂交,受精后5 min将受精卵放入3℃水中处理60 min诱导雄核发育二倍体泥鳅,并对其后代的血红细胞核体积、染色体核型、Ag-NORs带型及荧光原位杂交(FISH)信号等进行了研究。结果表明:对照组杂交三倍体泥鳅血红细胞核体积为(38.29±3.14)μm³,处理组雄核发育二倍体泥鳅血红细胞核体积为(27.92±3.58)μm³,二者血红细胞核体积之比为1.37∶1;杂交三倍体泥鳅胚胎染色体数目3n=75,核型公式为15m+6sm+54t,NF=96,雄核发育二倍体泥鳅胚胎染色体数目2n=50,核型公式为10m+4sm+36t,NF=64;杂交三倍体泥鳅胚胎染色体中,在3个染色体短臂的端部检测到3个FISH杂交信号,雄核发育二倍体泥鳅胚胎染色体中,在2个染色体短臂的端部检测到2个FISH杂交信号;杂交三倍体泥鳅染色体和间期核中,呈现出Ag-NORs数目为1~3个,雄核发育二倍体泥鳅胚胎染色体和间期核中,呈现出Ag-NORs数目为1~2个。研究表明,雄核发育二倍体泥鳅的染色体组构成为2套染色体组,表明自然四倍体雄性泥鳅能产生二倍体(2n)配子,该结果为自然四倍体雄性泥鳅是具有4套染色体组的遗传四倍体提供了重要的遗传学证据。     

Development and characterization of new allohexaploid resistant to web blotch in peanut

Peanut diseases seriously threaten peanut production, creating disease-resistant materials via interspecific hybridization is an effective way to deal with this problem. In this study, the embryo of an interspecific F_1 hybrid was obtained by crossing the Silihong(Slh) cultivar with Arachis duranensis(ZW55), a diploid wild species. Seedlings were generated by embryo rescue and tissue culture. A true interspecific hybrid was then confirmed by cytological methods and molecular markers. After treating seedlings with colchicine during in vitro multiplication, the established interspecific F_1 hybrid produced seeds which were named as Am1210. With oligonucleotide fluorescence in situ hybridization(Oligo FISH), molecular marker evaluations, morphological and web blotch resistance characterization, we found that: 1) Am1210 was an allohexaploid between Slh and ZW55; 2) the traits of spreading lateral branches, single-seeded or double-seeded pods and red seed coats were observed to be dominant compared to the erect type, multiple-seeded pods and brown seed coats; 3) the web blotch resistance of Am1210 was significantly improved than that of Slh, indicating the contribution of the web blotch resistance from the wild parent A. duranensis. In addition, 69 dominant and co-dominant molecular markers were developed which could be both used to verify the hybrid in this study and to identify translocation or introgression lines with A. duranensis chromosome fragments in future studies as well.     

苦瓜若干经济性状的遗传特点观察

利用差异明显的6个高代自交系组配了7个杂交一代组合,观察杂交一代苦瓜的皮色、果形、瘤状、果长、果径等形态特征和主蔓第一雌花节位、雌花率等与双亲之间的关系。结果表明:正交或反交后,F1代苦瓜的皮色介于双亲之间或偏向于浅色,果形亦介于双亲之间;尖瘤与圆瘤的正反交,F1代苦瓜均出现尖瘤,表现为尖瘤显性遗传;杂交一代主蔓第一雌花节位多数介于双亲之间,少数比双亲低。主蔓35节内雌花率介于双亲之间,并有倾向低雌花率的趋势;长形果与短形果的正反交,F1代果实均出现长形果,表现为长形果显性遗传;果径和果肉的正反交,F1代果径和果肉几乎介于双亲之间,并有倾大值亲本的现象。     

水稻雄性不育的遗传研究

本文对杂交水稻雄性不育系、恢复系、F_1,F_2,和由野生稻与栽培稻杂交的杂种F_1、F_2,以及回交低代的雄性不育性进行了遗传研究,认为水稻的雄性不育性是一个数量性状。     

野败型杂交籼稻恢复基因的遗传研究

以花粉可育率作指标,野败恢复系具有两对恢复基因 R_1R_1R_2R_2。R_1表现完全显性作用,R_2表现不完全显性作用和累加作用,F_2群体的育性分离比为13:2:1。等位测验表明,太引1号的 R_1基因与 IR24的 R_1基因是等位的。以结实率作指标,恢复系具有两对恢复基因 F_1F_1F_2F_2。F_2群体的育性分离比为9:6:1,恢复基因表现积加作用而无数量效应。等位测验表明,太引1号的两对恢复基因 F_1F_1F_2F_2与 IR24的两对恢复基因 F_1′F_1′F_2′F_2′互为等位。花粉可育率与结实率是两种不等而有相关的育性性状。自交结实率高的植株花粉可育率也高,但花粉可育率高的植株未必都是结实率高的植株,花粉可育率为零的植株无自交结实能力。因此,在选育恢复系时应以结实率作为育性指标,在选育或“提纯”不育系时应以花粉可育率作指标。恢复基因的遗传与穗颈节间中的酯酶同工酶谱无明显关系,与过氧化物酶同工酶谱的关系也不明显。     

Analysis of Genetic Diversity in Natural Populations of Psathyrostachys huashanica Keng Using Microsatellite (SSR) Markers

Psathyrostachys huashanica Keng is endemic to China and only distributed in Huashan Mountain in Shaanxi Province, China. In this study, 15 P. huashanica populations consisting of 450 individuals sampled across their main distribution were investigated by using the simple sequence repeats (SSRs) markers. A total of 184 alleles were detected on 24 SSR loci, and the number of alleles on each locus ranged from 2 tol5, with an average of 7.667. The total gene diversity (HT= 0.683) and the coefficient of population differentiation (GST=0.125) showed that P. huashanica had a relatively high level of genetic variation, and the genetic variation was mainly distributed within the populations. The gene flow among the populations of P. huashanica (Nm= 1.750) was much less than that of the common anemophytes (Nm = 5.24). Correlation analysis demonstrated that the number of alleles as well as genetic diversity of the five populations of Huangpu valley decreased along with the increase of altitudes, but the correlation was not significant. Implications of these results for future P. huashanica collection, evaluation and conservation were discussed.     

巨大冰麦草种质转移给普通小麦的研究 Ⅰ.(普通小麦×巨大冰麦草)F_1的产生

利用巨大冰麦草Elymus giganteus L.(2n=4x=28)对小麦赤霉病具有高抗扩展的特性,以普通小麦“中国春”(Triticum aestivum L.cv.Chinese Spring)为母本,巨大冰麦草为父本进行杂交,授粉1082朵小花,仅4朵小花子房膨大,于授粉后16天进行幼胚离体培养,3朵夭亡,1朵成苗。最终仅获得1株F_1植株。杂种形态介乎于父、母本的中间类型。经细胞学鉴定,染色体数为2n=5x=35。F_1花粉母细胞减数分裂中期Ⅰ有34.96个单价体,0.02个二价体。目前正进一步开展细胞遗传和育种利用研究。     

棉花二倍体合成异源四倍体新种的研究

各国棉花育种工作都在开展野生二倍体棉种的利用问题。试验用二倍体亚洲棉G。arboreum 2n(2x)=26,染色体组A_2,与野生比克氏棉G. bickii, 2n(2x)=26,染色体组G杂交,获得异源二倍体杂种。因二者亲缘关系最远,杂种高度不育。对A_2×GF_1PMC减数分裂观察,M_2染色体大都不配对,二价体变幅1—6对,并出现三价体,染色体构型为1.64Ⅰ+4.0Ⅱ+0.4Ⅲ。平均交叉频率为1.07个。由于四分体发育不正常,形成畸形败育花粉,导致杂种F_1高度不育。对A_2×G F_1进行染色体加倍,合成异源四倍体,观察F_2PMC减数分裂时,染色体数为52条。MI,大都配对,交叉频率为1.83,大多数为环状二价体。染色体构型为:2.75Ⅰ+24.5Ⅱ+0.25Ⅲ。其中完全配对成26个二价体的细胞数占30％。后期Ⅰ,染色体平均分配,两级各有26条,形成正常的四分体,花粉生活力达89％杂种植株育性恢复,每株结铃平均为33个,每铃种子平均9.1粒,为人工合成异源四倍体新种质     

Impacts of Sletr1-1 and Sletr1-2 mutations on the hybrid seed quality of tomatoes

Shelf life is an important breeding trait in tomato, especially for the tomato production in subtropical and tropical regions. Previously we have isolated and characterized ethylene receptor mutants, Sletr1-1 and Sletr1-2 from mutant population based on Micro-Tom cultivar. Sletr1-1 showed insensitivity to ethylene while Sletr1-2 showed reduced sensitivity to ethylene. We also have demonstrated that the traits are useful for extending fruit shelf life of the hybrid tomato cultivars. For commercializing the hybrid cultivars, the seed quality is another important trait. In this study, we evaluated the effects of the Sletr1-1 and Sletr1-2 mutations on the seed quality characteristics of F_1 hybrid lines generated by crossing Sletr1-1 and Sletr1-2 with three commercial tomato cultivars, Intan, Mutiara and Ratna. Sletr1-1 mutation conferred insensitivity to ethylene in the F_1 hybrid seedlings, resulting in negative effects including reduced germination rate, vigor index and emergence speed index. Interestingly Sletr1-2 mutation had almost no effect on the seed quality characteristics of the F_1 hybrid lines, suggesting that Sletr1-2 was suitable for producing high quality of hybrid seeds.     

(苏丹草×拟高梁)种间杂种主要特征特性及细胞学分析

利用人工去雄、多次授粉法获得(苏丹草×拟高梁)F_1种间杂种。苏丹草(2n=20)与拟高梁(2n=20)杂交结实率及杂种发芽率均较低,正反交存在较大的差异.F_1杂种形态和饲草品质介于双亲之间,雌雄配子均具有一定的孕性。杂种对叶斑病表现较强的抗性。F_1花粉母细胞减数分裂染色体配对较为正常,98.8%的细胞均形成10个二价体,无多价体出现,具单价体的细胞频率仅为1.2%,表明双亲在细胞学上具有较高的同源性。F_2和 BC_1代植株形态、结实率和抗病性等差异较大,分离出饲草品质较好、落粒性弱、种子产量高和抗病性较强的中间型植株,这些后代可能对苏丹草抗病育种或拟高粱品质育种有重要的利用价值。     

野生二粒小麦与二倍体野燕麦远缘杂交后代的核型分析及进化关系

对野生二粒小麦与二倍体野燕麦远缘杂交后代进行染色体核型分析。结果表明：杂交后代084株系的核型公式为2n=6x=42=36m(4SAT)+6sm，核型为1A，为极对称核型，属于原始类型；野生二粒小麦、二倍体野燕麦及084株系的进化指数分别为1、4和1，表明084株系的进化程度与野生二粒小麦一致，低于二倍体野燕麦；084株系的染色体相对长度较亲本大，且其平均臂比、核型不对称系数及臂比大于1.7的染色体比例均在野生二粒小麦与二倍体野燕麦之间，说明远缘杂交在一定程度上对加速小麦属的进化有重要意义；084株系染色体臂比与母本的相近，且存在4对染色体与父本的相对长度和臂比极为相近，核型分析结果从一定程度上证明了野生二粒小麦与二倍体野燕麦杂交后代的真实性。     

栽培因子对转基因棉F_1、F_2纤维品质影响的优化模型研究

采用四元二次回归旋转组合设计,对影响转基因杂交棉F1、F2纤维品质的密度、施氮量、施钾量和缩节胺施用量进行了综合研究,结果表明,缩节胺与密度是影响F1纤维品质指标的关键因子,而密度是影响F2纤维品质指标的关键因子。密度对F1、F2的纤维品质均有显著作用。密度与施钾量的互作对F1纤维品质起关键作用,而密度与缩节胺、密度与施氮量的互作对F2纤维品质指标的影响最显著。建立了4个栽培因素对F1、F2纤维品质影响的最优数学模型。     

Construction and Characterization of Grass Carp （Ctenopharyngodon idellus） Fosmid Library

Grass carp （Ctenopharyngodon idellus） genomic fosmid library cotaining 129 014 clones was constructed and characterized from one diploid grass carp. The average insert size of the fosmid library was determined to be 35 kb by pulsed field gel electrophoresis, which is 4.1-fold coverage of the grass carp genome. To demonstrate the probability of picking the functional genes from the library, eleven functional genes were screened by three-dimensional PCR technique. The number of positive clones of these genes was from 1 to 6. So, this library may screen any useful genes from grass carp. This grass carp genome fosmid library will be integrated in the presently ongoing efforts to determine the sequence of the grass carp genome.     

普通小麦-华山新麦草人工合成双二倍体AFLP标记多态性分析

【目的】从分子水平上了解普通小麦-华山新麦草双二倍体(PHW-SA)合成过程中遗传变异情况。【方法】用195对引物对PHW-SA及其亲本普通小麦(J-11)和华山新麦草进行AFLP标记分析。【结果】J-11、华山新麦草和PHW-SA分别扩增出标记5 136、3 953和5 637条,分别占总标记(17 726条)的29.0%、22.3%和31.8%。81.8%的J-11标记和49.6%的华山新麦草标记存在于PHW-SA中。其中J-11与PHW-SA特有相同标记2 484条,分别占各自标记的48.4%和44.1%;华山新麦草与PHW-SA特有相同标记246条,分别占各自标记的6.2%和4.4%;PHW-SA特有标记232条,缺失双亲共有标记66条,分别占PHW-SA总标记的4.1%和1.2%;3种材料共有相同标记1 715条,分别占J-11、华山新麦草和PHW-SA总标记的33.4%、43.4%和30.4%。【结论】PHW-SA在合成过程中基因组发生了较大的遗传变异。此研究结果为PHW-SA在小麦遗传育种中的应用提供了基础理论依据。     

(亚洲棉×司笃克氏棉)不同倍性杂种一代的育性和花粉母细胞减数分裂行为的研究

亚洲棉与司笃克氏棉杂交,获得了125粒杂种种子,用0.05%秋水仙素水溶液处理,获得7株加倍的四倍体F_1植株。1984-1987年的研究结果表明,二倍体F_1花粉母细胞减数分裂不正常,中期Ⅰ染色体构型是20.53Ⅰ+2.45Ⅱ+0.19Ⅲ,二价体交叉频率为1.07;后期Ⅰ和后期Ⅱ染色体分向两级不均衡,产生各种类型的异常四分孢子,由此发育的花粉无生活力,用亚洲棉回交或自然授粉均未结铃。四倍体F_1减数分裂较正常,中期Ⅰ染色体构型为0.1Ⅰ+25.9Ⅱ,二价体交叉频率为1.96,后期Ⅰ和后期Ⅱ染色体走向两极较均衡,产生的花粉部分可育,授陆地棉花粉或自然授粉能结少数种子。     

东北梅花鹿与东北马鹿种间杂交F#-1能育性的细胞遗传学基础的研究

 本文对东北梅花鹿与东北马鹿的F#-1代杂种鹿的能育性进行了研究。从F#-1的染色体组型、G带、C带和Ag—NORs的观察表明，F#-1双亲鹿的染色体高度同源，差异只涉及一个罗伯逊易位；精母细胞联会复合体显示出F#-1减数分裂时，同源染色体能很好的配对，形成31个完整的常染色体联会复合体，1个端着丝粒染色体/中着丝粒染色体的三价体和XY双价体。三价体的顺式构型有利于同源染色体能平均分配到子细胞中而产生平衡配子；睾丸组织切片证实了F#-1的生殖腺生长发育正常。所以，F#-1两性皆育。说明其亲本鹿之间隔离机制不完善。这两种鹿应属同一个孟德尔群体。     

杂交棉中棉所57号F1和F2代产量构成及纤维品质性状空间分布比较

[目的]旨在进一步明确该杂交棉F2代与F1代相比在产量和品质方面的下降趋势和程度,为更好地发掘和利用F2代杂种提供理论依据。[方法]以在南疆广适种植的转基因抗虫杂交棉中棉所57号的F1和F2代为试验材料,设置3种种植密度,分取6个铃位,按照《棉花种质资源描述规范和数据标准》对其进行农艺经济性状与纤维品质的调查、鉴定和评价,最终对F1和F2代杂交种进行产量比较。[结果]在铃重、衣分和子指空间分布上,F2代比F1代丰产株型的竞争优势略有减弱;纤维品质表现上,也有R代分离造成的下降趋势,但均没有达显著性差异。[结论]最终皮棉产量,F2代则以22．5万彬hm^2高密度种植为最高,F1代以18．0万株／hm^2。种植密度次之。     

同源四倍体矮脚黄白菜与芸苔属作物杂交的亲和性

以选育的同源四倍体矮脚黄白菜为母本,选用其亲本二倍体矮脚黄及其它白菜品种,以及大白菜、甘蓝、甘蓝型海莱、芥菜等为父本,分别进行人工杂交,所得F_1种子中的杂株率有差异:二倍体矮脚黄为父本的是1.7％,其反交为6％;黑心乌白菜和甘蓝为父本的都是0;而芥菜和甘蓝型油为菜父本的分别是31％和36％。但是统计其杂种指数,则皆小于1,表现杂交不亲和。 连续三年调查了同源四倍体矮脚黄自然授粉采种的杂株率,平均为0.59％,但杂株中又以芥型和甘蓝油菜型较多,平均占65.0％和22.5％;而二倍体矮脚黄在同样条件下却高达16.5％。由此可见,同源四倍体矮脚黄在留生产种时,只需与芥菜和甘蓝型油菜隔离即可。     

油用亚麻两系杂交种产量表现及不育株率对产量的影响

通过田间试验,对几个利用温敏雄性不育亚麻雄性不育系配制的杂交种的产量表现及不育株率和不育株率对产量的影响进行了分析。结果表明,亚麻杂交种和常规品种相比,具有显著产量优势。不育株和正常可育株相比,产量性状明显偏低,因此,杂交种不育株率的高低将影响杂交种的产量。