共查询到20条相似文献，搜索用时 765 毫秒
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中国苎麻属无融种综发现初报臧巩固，赵立宁（中国农业科学院麻类研究所湖南沅江４１３１００）无融合生殖是指不经配子融合而产生胚的生殖方式，属植物三大繁殖体系（有性生殖、无融合生殖、营养生殖）之一。目前已在３５科３００多种植物中发现了无融合生殖。无融种综（... 相似文献
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扼要介绍了植物无融合生殖的概念及其在水稻杂种优势利用中的意义，评述了国内获得的一些水稻无融合生殖材料的利用价值，分析了水稻无融合生殖尚难应用的原因，并展望了其前景。 相似文献
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蔬菜育种的三向选择策略及其定量化实施方法初探 总被引：1，自引：1，他引：1
在分析现有蔬菜育种技术的特点和杂种优势育种中存在的问题的基础上,从杂种优势育种中自交系的选育理论和国内外的蔬菜育种实践中,概括、总结出蔬菜育种的三向选择策略,即基于从选育出的材料直接应用于目前的新品种育种实践的目标考虑,在对一基本材料的分离世代(如F2代)进行选择时,除以对照品种为依据,按有性杂交育种途径经多代选择选育出新品种外,还可按照杂种优势育种目标中对母本、父本的要求,经多代选择选育出母本自交系、父本自交系。实践中,三向选择策略的实施方法有定性法和定量法2种,但定量法能更大程度地提高育种效率,将更受育种者的青睐。初步从遗传上探讨了三向选择策略在杂种优势育种中的两种定量化实施方法:1)以对照品种为依据,2)以杂种优势预见性育种理论为依据。这2种定量化实施方法,均解决了亲本自交系的选择指标定量化这一难题,从而可以定向选育亲本,提高了杂种优势育种的预见性和育种效率。 相似文献
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利用无融合生殖改良作物的潜力 总被引：14，自引：2，他引：14
一、无融合生殖的概念 无融合生殖是一个新的研究领域。无融合生殖是不通过受精作用而产生种子的生殖方式,它包括单倍体和二倍体两种无融合生殖。对作物改良意义最大的是二倍体无融合生殖。被子植物的二倍体无融合生殖可以有3种不同的途径: 1.二倍体孢子生殖胚囊由孢原细胞或大孢子母细胞不经减数分裂发育而成。 2.无孢子生殖由胚珠中的体细胞直接发育成胚囊。 3.不定胚由胚珠的体细胞(多为珠心)直接发育成胚。 现将有性生殖和二倍体无融合生殖的途径图解如下: 二、作物育种利用 无融合生殖的意义 二倍体无融合生殖可使世代更迭但不改变基因… 相似文献
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前言 很少有基因能象控制无融合生殖的基因那样,对世界食物、饲料和纤维产品的质量改进和数量增加具有较大的影响。基于这种原因,我们倾注了大部份的研究精力来致力如下方面的研究:(1)证实无融合生殖基因能从野生种转到栽培种中;(2)鉴定能够被克隆并能应用于其他属杂种优势固定或产生不分离杂种的无融合生殖基因;(3)选育无融合生殖或不分离的珍珠粟杂种。用于无融合生殖基因转移的常用方法包括:(1)自然重组,(2)染色体代换,(3)花粉和细胞悬浮培养物的r-射线辐照,(4)体细胞变异,(5)DNA转移。 珍珠粟突变体 随着由辐射诱导茬柱产生的兼性无融… 相似文献
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花粉诱导是获得无融合生殖的一个重要途径。本试验采用辐射花粉对雌花授粉进行木薯无融合生殖活体诱导,获得了由~(60)Coγ射线辐射花粉诱导的孢子体无融合生殖种质。结果表明:~(60)Coγ射线辐射花粉诱导木薯无融合生殖的途径是有效的,且辐射剂量及品种的选择对木薯无融合生殖诱导具一定的影响。本次试验共收获23株植株,通过对诱导子代的细胞学及共显性EST-SSR分子标记检测,显示其23株诱导子代为杂合二倍体;进一步采用SRAP分子标记对各子代的异质杂合性或同质杂合性鉴定,发现2株为SC5遗传同质体。 相似文献
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本文对植物无融合生殖的类型、意义、研究现状及其在作物育种中的应用进行介绍和评论；同时论述苎麻无融合生殖的研究现状及前景。 相似文献
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水稻双胚苗的发现及其研究进展 总被引：2，自引：0，他引：2
著名杂交水稻育种专家袁隆平提出了杂交水稻育种分为三个发展阶段的战略设想,即:三系法品种间杂种优势利用,两系法亚种间杂种优势利用和一系法远缘杂种优势利用。“一系法”即利用无融合生殖法固定水稻品种间及更远缘的强大的杂种优势。这既是人们愿望,也是杂种优势育种发展的最高阶段。利用无融合生殖特性来固定杂种优势,成功的关键在于获得水稻的二倍体无融合生殖材料。早在1979年袁老师就对我们提出了固定杂种优势的途径和寻找无融合生殖材料的方法。其中不定胚就是二倍体无融合生殖的方式之一。它的主要表现形式是多胚现象。因此从大量… 相似文献
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一系法杂交水稻研究的技术策略探讨 总被引：8，自引：1，他引：7
通过一系法利用和固定水稻的远缘杂种优势是一项具有极大诱惑力但难度颇大的科研难题。我国水稻无融合生殖研究尚处在探索性阶段,还没有筛选到具有实用价值的无融合生殖种质。由于多倍体水稻的有性生殖能力明显变弱,在多倍性水平筛选和创造水稻无融合生殖种质有可能成为一系法杂交稻研究的突破口。 相似文献
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Ulisses Jos de Figueiredo Sanzio Carvalho Lima Barrios Cacilda Borges do Valle Jos Airton Rodrigues Nunes 《Grass and Forage Science》2019,74(4):678-686
The diallel cross constitutes an informative genetic design for choosing genitors and crosses in breeding programmes since it provides estimates of general (GCA) and specific (SCA) combining abilities. Because the breeding programme for Urochloa humidicola ([Rendle] Morrone & Zuloaga; syn. Brachiaria humidicola [Rendle] Schweick) at Embrapa Beef Cattle is recent, these estimates are still unknown. Thus, the aim of this study was to obtain the estimates of GCA and SCA from the partial diallel cross design between sexual and apomictic parents. The crosses involved nine sexual and ten apomictic parents. Seventy‐one full‐sib progenies were obtained and evaluated in an incomplete block design, using all parents and the cv. BRS Tupi as a check. The agronomic and forage quality traits were evaluated using seven harvests. Statistical analysis was performed using the mixed model approach. Significant variations were associated with GCA among sexual parents for biomass yield and forage quality traits. However, this cannot be observed for apomictic parents for GCA. The SCA effect was not significant for the assessed traits. These results showed the predominance of additive effects. Sexual parents SEX3 and SEX4 presented the highest potential for contributing favourable alleles in hybrid combinations. The absence of GCA among apomictic parents and SCA suggests the need to increase genetic variability for the generation of breeding populations of U. humidicola. 相似文献
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我国水稻无融合生殖研究现状及展望 总被引：1，自引：0，他引：1
本文介绍了无融合生殖的基本概念及其固定杂种优势的原理，对我国已获得的、具有某些无融合生殖特征的水稻材料，进行了分析，并对进一步开展水稻无融合生殖研究提出了看法。 相似文献
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E. L. Colomba K. Grunberg S. Griffa A. Ribotta L. Mroginski† E. Biderbost 《Grass and Forage Science》2006,61(1):2-8
Buffel grass (Cenchrus ciliaris L.) is an important apomictic grass used as forage for ruminant livestock. Biotechnological methods provide opportunities for producing new germplasm. Mature embryos of fourteen buffel grass apomictic cultivars (2n = 4x = 36) were used to induce embryogenic callus formation using a basal medium supplemented with 3% sucrose and with the testing of five concentrations of 2,4‐dichlorophenoxyacetic acid (2,4‐D) and four concentrations of 6‐benzylaminopurine (BAP). The effects of cultivar and culture medium on callus induction and plant regeneration were evaluated. Significant differences were observed among the fourteen cultivars and the five concentrations of 2,4‐D (P < 0·01). Values for embryogenic callus production varied from 0 to 86·7. Most cultivars showed the highest level of embryogenic callus production on the medium with the concentration of 3 mg L?1 2,4‐D. The addition of different BAP concentrations in combination with 2,4‐D in the medium inhibited embryogenic callus growth and did not permit plant regeneration. The data clearly demonstrated that the genotype and concentrations of 2,4‐D had significant effects both on the frequency of embryonic callus formation from mature embryos and on the subsequent efficiency of plant regeneration of apomictic cultivars of buffel grass. Cultivars Biloela and Nunbank showed the greatest efficiency in in vitro culture response. 相似文献
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Yasmin Vasques Berchembrock Ulisses José de Figueiredo José Airton Rodrigues Nunes Cacilda Borges do Valle Sanzio Carvalho Lima Barrios 《Grass and Forage Science》2020,75(2):145-152
Hybridization in the Urochloa humidicola breeding programme allowed to explore the genetic variability of the apomictic sources and, thus, to obtain new sexual and apomictic parents with compatible ploidy and/or superior progenies. However, given the high variability arising from crosses, there is a need to adopt efficient selection strategies among and within progenies. The aim of this study was to compare the selection methods among U. humidicola progenies with (t-BLUP) and without (BLUP) the weighting based on prediction error and subsequent selection within progenies by individual simulated (BLUPIS) or optimal individual BLUP. We evaluated seventy-one U. humidicola full-sib progenies from biparental crosses between nine sexual and ten apomictic parents. The experiment was set up in an incomplete block design with 64 blocks of 15 plots each, consisting of individual plants. Seven consecutive cuts were made and the traits total dry-matter, leaf dry-matter and regrowth scores were measured. Genetic variance was expressive for all traits. The selection procedure among progenies of U. humidicula based on t-BLUP proved to be more advantageous regarding the use of BLUP not weighted by the prediction error, resulting in higher selection gains, taking as reference the optimal procedure of the individual BLUP. Furthermore, the use of BLUPIS allowed an optimized selection of hybrids, allowing the breeder to explore with variable selection intensity the genetic variability within the selected full-sib progenies based on relative genetic merit. 相似文献
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S. Griffa D. Díaz† A. Ribotta S. Lanza Castelli N. Muñoz E. López Colomba C. Luna K. Grunberg E. Biderbost 《Grass and Forage Science》2006,61(4):454-458
Buffel grass (Cenchrus ciliaris L.) is an apomictic species that is widely adapted to arid and semi‐arid, tropical and warm climates. Six apomictic cultivars used as male parents, one sexual line used as the female parents and 15 putative F1 genotypes were studied using the amplified fragment length polymorphism (AFLP) technique for their evaluation and recognition. The NTSYS programme and Jaccard's Index were used to establish the genetic similarity; and a phenogram was constructed. A total of 152 bands was recorded. Three primer combinations were sufficient to identify the genotypes. The maximum proportion of polymorphisms was 0·835, and 0·510 of the polymorphisms consisted in individual bands that strictly diagnosed unique genotypes. Texas 4464 and Americana cultivars were the most different from the sexual line, indicating that they might be the best genotypes for future crossing. Two hybrids were identified among F1 material to demonstrate the usefulness of the AFLP technique in characterizing genotypes and recognizing hybrids in Buffel grass for breeding purposes. 相似文献
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L. L. Couso M. L. Gatti P. S. Cornaglia G. E. Schrauf R. J. Fernández 《Grass and Forage Science》2010,65(3):296-303
Paspalum dilatatum Poir., is a perennial C4 grass widely distributed in the Argentinean Pampas. The response to water availability for materials developed with forage‐production purposes is unknown. We hypothesized that genetic differences between commercial varieties are reflected in their regrowth capacity under water stress. The effect of five levels of constant water supply on three plant varieties (two derived from apomictic materials: ‘Relincho’ and ‘Alonso’ and one from sexually‐derived material: ‘Primo’) were examined in the greenhouse. Leaf‐ and plant‐response traits were followed during 38 d after a single defoliation event. Seven response variables were measured: three of them were morphogenetic (leaf elongation rate, leaf appearance rate and leaf elongation duration) and four were structural (number of live leaves, lamina length, tiller biomass and tiller production). The sexual material showed higher values for growth variables than the apomictic varieties (leaf elongation rate, leaf length and tiller biomass) across the environmental range. Apomictic varieties showed a proportionally similar drought response to the sexual material for the seven variables. No intra‐specific trade‐off (statistical interaction) was found between growth under high water availability conditions and drought tolerance. 相似文献
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水稻无孢子生殖的胚胎学研究 总被引：12，自引：0，他引：12
为进一步确定水稻HDAR的无融合生殖胚的倍性及发生类型，系统观察了胚囊的发生发育。结果表明水稻HDAR中具有一定频率的无孢子生殖胚囊和由卵细胞孤雌生殖而形成的无融合生殖胚。 相似文献
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《Industrial Crops and Products》2001,13(3):229-238
Plant breeding in guayule, a rubber and latex producing plant, has not been as effective as predicted or desired. A surprisingly large amount of variability has been reported in this apomictic crop for traits such as plant height, width, resin, rubber, and latex contents. This study was designed to calculate the proportion of the total measured variability due to the environment and the proportion due to genetic influences within and between three-released germplasm lines. Plant heights were measured at 1, 2 and 3-years-of-age; plant width, and latex contents at 2 and 3-years-of-age; and resin and rubber content at 2-years-of-age. Broad-sense-heritabilities were estimated for each trait and year by dividing the genotypic by the total variance. To estimate the genetic component of the measured variance for each trait, the environment effects (variance from clonally propagated plants) were subtracted from the total variance (variance from open-pollinated (OP) seed propagated plants). In general, the variances of the means for the measured traits were lower in the clonally propagated plants compared with the apomictic OP seed propagated plants. The heritability estimates calculated for each trait differed from year to year. For instance, heritability for plant height was estimated in line AZ-2 to be 0.84 at 1 year of age; 0.47 at 2 years of age; and 0.0 at 3 years of age. These values imply that a large portion of the observed variation in this line is attributed to genetic effects in the first 2 years of growth. As the plant grows over several seasons, the environment effects compound, masking the genetic effects, making effective selection choices more difficult. Heritability for latex content for the same line was estimated to be 0.97 for the second year and 0.55 for the third year. Selections for the measured traits in this study appear to be most effective during the first and second years of growth, with effectiveness diminishing during the third year. Most selections previous to this study were performed between 3 and 5 years of growth, thus suggesting one reason for the lack of significant progress in most breeding programs. 相似文献