《分子植物育种》中文网络版

<正>《分子植物育种》(中文网络版,ISSN 1923-8258)是一本基于同行评审、开放取阅以及在线即时发表的期刊。主要发表植物育种领域中关于转基因育种与分子标记辅助育种的新知识与先进技术的原始研究论文。本刊致力于为转基因育种与分子标记辅助育种服务,主要发表在植物育种领域中涉及的分子遗传育种理论、分子育种技术与方法、分子育种产品研发等方面的基础和应用研究。所有发表的研究论文都应是在植物育种领域中具有创新意义的最新研究,特别是转基因、分子遗传学、作物QTL分析、种质资源的遗传多样     

雄配子体选择的遗传分化效应及其在植物改良中的应用

在植物世代交替的生活史中,配子体是产生配子和具有单倍数染色体的植物体,并且有自己的遗传表达信息.在配子产生的过程中以及配子结合之前,适者生存的法则对配子发挥着选择作用,只有最适应外界环境条件的配子才能通过竞争性受精并产生合子.雄配子体选择是影响植物遗传分化、演变和遗传多样性的重要因素,被认为是生物进化的有力动力.此外,由于植物基因组中约有2/3的基因表达交错发生在配子体阶段和孢子体阶段,因此雄配子体选择的结果会影响到下一代孢子体的表现型.在育种实践中,利用雄配子体选择对植物进行遗传改良,具有提高选择机率和缩短育种年限等优点.本文主要概述雄配子体选择与孢子体表型的关刎系、遗传分化效应及其在植物遗传改良中的应用,以期为雄配子选择相关研究提供参考     

SRAP标记及其在植物遗传育种中的应用

SRAP标记是基于选择性扩增开放性阅读框的新型分子标记,具有简便、高效、重复性好、高共显性等优点,在植物育种中已经得到广泛应用.本文介绍了SRAP标记基本原理和特点,对SRAP标记在遗传多样性研究、遗传连锁图谱构建、比较基因组以及分子标记辅助选择育种等方面的应用进行了综述.     

《分子植物育种》中文网络版

<正>《分子植物育种》(中文网络版,ISSN 1923-8258)是一本基于同行评审、开放取阅以及在线即时发表的期刊。主要发表植物育种领域中关于转基因育种与分子标记辅助育种的新知识与先进技术的原始研究论文。本刊致力于为转基因育种与分子标记辅助育种服务,主要发表在植物育种领域中涉及的分子遗传育种理论、分子育种技术与方法、分子育种产品研发等方面的基础和应用研究。所有发表的研究论文都应是在植     

叶分子植物育种曳中文网络版

<正>《分子植物育种》(中文网络版,ISSN 1923-8258)是一本基于同行评审、开放取阅以及在线即时发表的期刊。主要发表植物育种领域中关于转基因育种与分子标记辅助育种的新知识与先进技术的原始研究论文。本刊致力于为转基因育种与分子标记辅助育种服务,主要发表在植物育种领域中涉及的分子遗传育种理论、分子育种技术与方法、分子育种产品研发等方面的基础和应用研究。所有发表的研究论文都应是在植     

《分子植物育种》中文网络版

<正>《分子植物育种》(中文网络版,ISSN 1923-8258)是一本基于同行评审、开放取阅以及在线即时发表的期刊。主要发表植物育种领域中关于转基因育种与分子标记辅助育种的新知识与先进技术的原始研究论文。本刊致力于为转基因育种与分子标记辅助育种服务,主要发表在植物育种领域中涉及的分子遗传育种理论、分子育种技术与方法、分子育种产品研发等方面的基础和应用研究。所有发表的研究论文都应是在植     

《分子植物育种》中文网络版

<正>《分子植物育种》(中文网络版,ISSN 1923-8258)是一本基于同行评审、开放取阅以及在线即时发表的期刊。主要发表植物育种领域中关于转基因育种与分子标记辅助育种的新知识与先进技术的原始研究论文。本刊致力于为转基因育种与分子标记辅助育种服务,主要发表在植物育种领域中涉及的分子遗传育种理论、分子育种技术与方法、分子育种产品研发等方面的基础和应用研究。所有发表的研究论文都应是在植     

表观遗传标记在猪分子育种中的研究与应用前景

家畜动物的表型是由基因组、表观基因组和环境等多种因素相互影响共同作用决定的。近年来,随着遗传育种领域的迅速发展,表观遗传标记在猪分子育种中的研究受到越来越多科研人员的关注。表观遗传学是研究基因表达发生可遗传的改变而DNA序列不发生改变的一门生物学分支学科,其遗传标记主要包括DNA甲基化、组蛋白修饰、非编码RNA、印记基因等。越来越多的研究表明,表观遗传标记在猪的遗传性状中发挥着重要作用,主要通过调控与性状相关基因的表达进而达到改变生物表型的目的。然而,在当前猪分子育种领域,表观遗传标记的作用还没有得到足够的重视,影响猪重要性状的机制还没有得到深度解析,因此在实际应用中还缺乏足够的科学依据和可操作性。本文从营养、疾病、重要经济性状以及隔代遗传几个方面综述了表观遗传标记在猪分子育种中的研究现状、应用前景以及遇到的挑战,以期为表观遗传标记在猪分子育种中的应用提供较全面的理论依据。     

SRAP与TRAP标记及其在园艺植物研究中的应用

SRAP与TRAP是最近发展的新型分子标记系统,具有简便、高效、重复性好等优点,已在园艺植物遗传育种和种质资源研究的各个方面得到广泛应用.本文介绍了SRAP和TRAP标记的原理、特点,综述了这两种新型分子标记在园艺植物遗传图谱构建、遗传多样性分析以及比较基因组学研究等方面的应用,并对其应用前景进行了展望.     

作物基因聚合分子育种

基因聚合分子育种与常规育种技术相结合已成为今后作物育种的主流方向。基因聚合分子育种主要包括遗传转化基因聚合分子育种和分子标记筛选基因聚合分子育种。本文简要综述了近年来作物基因聚合分子育种的研究进展,分析了遗传转化基因聚合分子育种以及分子标记基因聚合分子育种技术的研究方法及基因聚合分子育种存在的问题。     

2n gametes in the potato: essential ingredients for breeding and germplasm transfer

2n gametes are the result of meiotic mutations occurring during micro – and mega-sporogenesis. They have been identified in several plant species of different taxa. The potato is probably the crop plant where they have been most intensively studied and also more appropriately used for the genetic improvement of cultivated genotypes. This paper reviews how 2n gametes allow potato breeders to broaden the genetic basis of the cultivated Solanum tuberosum, introducing both new genes for the improvement of traits of interest and allelic diversity to maximize heterozygosity. We provide molecular and breeding evidence that, in the potato, 2n gametes represent a unique tool to transfer target genes from wild forms to the cultivated tetraploid gene pool. In fact, species directly crossable to S. tuberosum haploids can be exploited through sexual polyploidization crossing schemes. For those which have developed crossability barriers, specific crossing schemes based on ploidy bridges can be designed. In this paper we also give possible hypotheses to explain conflicting results on the genetic control and meiotic mutations responsible for 2n-gamete formation in the potato. Received: 22 February 2000 / Accepted: 29 February 2000     

Multilocus half-tetrad analysis and centromere mapping in citrus: evidence of SDR mechanism for 2n megagametophyte production and partial chiasma interference in mandarin cv 'Fortune'

The genetic structure of 2n gametes and, particularly, the parental heterozygosity restitution at each locus depends on the meiotic process by which they originated, with first-division restitution and second-division restitution (SDR) being the two major mechanisms. The origin of 2n gametes in citrus is still controversial, although sexual polyploidisation is widely used for triploid seedless cultivar development. In this study, we report the analysis of 2n gametes of mandarin cv 'Fortune' by genotyping 171 triploid hybrids with 35 simple sequence repeat markers. The microsatellite DNA allele counting-peak ratios method for allele-dosage evaluation proved highly efficient in segregating triploid progenies and allowed half-tetrad analysis (HTA) by inferring the 2n gamete allelic configuration. All 2n gametes arose from the female genitor. The observed maternal heterozygosity restitution varied between 10 and 82%, depending on the locus, thus SDR appears to be the mechanism underlying 2n gamete production in mandarin cv 'Fortune'. A new method to locate the centromere, based on the best fit between observed heterozygosity restitution within a linkage group and theoretical functions under either partial or no chiasmata interference hypotheses was successfully applied to linkage group II. The maximum value of heterozygosity restitution and the pattern of restitution along this linkage group would suggest there is partial chiasma interference. The implications of such a restitution mechanism for citrus breeding are discussed.     

The occurrence and frequency of 2n pollen in three diploid solanums from Northwest Argentina

Summary A group of wild, tuber-bearing species from Northwest Argentina, belonging to the series Tuberosa, Solarium spegazzini Bitt. (spg, 2n=2x=24), S. gourlayi Hawkes (grl, 2n=2x=24 and 2n=4x=48) and S. oplocense Hawkes (opl, 2n=6x=72), and Cuneolata, S. infundibuliforme Phil (ifd, 2n=2x=24), is being used to investigate the mode of origin of polyploids in the genus Solanum. 2n gametes have been detected in the diploid species ifd and spg and in a diploid race of grl, using cytological and breeding approaches. Twenty-two introductions of spg, 8 of grl and 26 of ifd have been tested for 2n pollen; 59%, 63% and 54% of them, respectively, had at least one 2n pollen producing plant. These introductions comprised 238, 76 and 235 plant respectively, of which 20, 16, and 32 plant produced 5% or more 2n pollen. The mechanism of 2n pollen formation was determined in several plant of 2x spg, 2x grl and 2x ifd. All of them were found to form diplandroids via parallel spindles. This mechanism, which gives meiotic products genetically equivalent to first division restitution gametes, is under control of the Mendelian recessive ps. The results suggest that the allele ps is widely distributed in natural populations of the three diploids, and that its frequency is very high. These species are seen as valuable material for population genetic studies, and for the eventual incorporation into a breeding scheme involving sexual polyploidization via 2n gametes.     

Sexual polyploidization and depolyploidization: some terminology and definitions

Summary Sexual polyploidization (deployploidization) is the process through which a euploid zygote is formed whose chromosome number is increased above (decreased below) the level that would be expected if each parent contributed a gamete carrying one-half the parental premeiotic chromosome number. One or both gametes may contribute (lack) the extra genome (s) so that these processes may be unilateral or bilateral. Sexual polyploidization has the distinctive characteristic of being a genetically innovative mechanism. This is believed to be its most significant difference with respect to somatic doubling. Sexual depolyploidization, which may be conceived to arise in some rare situations, also has the capacity for innovation. Several cytological mechanisms may be envisioned which give rise to polyploidizing gametes. The genetic consequences of these mechanisms can be markedly different in regards to gene reassortment. Short of a mitotic-like method, FDR (first division restitution) appears to be the most appropriate mechanism to attain such a goal. Other modified meiotic processes generally result in more disturbance of the premeiotic genotypes. Under these circumstances, sexual polyploidization is probably associated with mitigated heterotic responses and a more extensive release of genetic variability.As a cytological device, FDR has the unique property of producing balanced 2n gametes even after a numerical nondisjunction has occurred. This simple mechanism may restore fertility to, e.g., monoploids and triploids, so that odd-ploids may possess more evolutionary significance by acquiring a means of producing balanced gametes systematically.Some new terminology is proposed to designate gametes and gametophytes which conserve the parental number of chromosomes, and for polyploids arising in conjunction with their functioning in fertilization.     

大豆SSR标记辅助遗传背景选择的效果分析

本研究利用鲁豆4号回交转育的大豆种子脂氧酶缺失株系为材料,用IEF-PAGE鉴定大豆种子脂氧酶缺失基因,SSR标记进行遗传背景分析,通过遗传背景回复率相关分析,探索分子标记辅助遗传背景选择时所需的适宜的标记数和选择方式,期望获得可进一步回的鲁豆4号脂氧酶缺失株系。研究明确了大豆SSR标记辅助背景选择时适宜标记数目和选择方式,即先用少数标记初筛,选出遗传背景回复率较高的材料,再用适宜标记鉴定,随着世代递增,已恢复为轮回亲本的标记住点不再分析,逐代减少选择标记数目。获得了合有脂氧酶缺失基因,遗传背景与鲁豆4号差异较小的株系,可用鲁玉4号进一步回交,从而加速培育鲁豆4号脂氧酶缺失近等基因系。     

Mechanisms of unreduced gamete formation in flowering plants

Unreduced gametes play a fundamental role in speciation of flowering plants, asexual reproduction of plants, and restoration of fertility of distant hybrids used to produce new varieties with breeding-valuable traits. Unreduced gametes are formed as a result of meiotic restitution. To date, a large body of data has been accumulated on the types of meiotic restitution in dicots and monocots. However, there is no clear idea on the cytological mechanisms of this process. In this review, we systematize and analyze all currently known mechanisms of restitution in plants. New data on the mechanisms and genetic regulation of unreduced gamete formation in intergeneric wheat hybrids are presented.     

葫芦科瓜类作物分子标记辅助育种研究进展

综述了几种常用分子标记在葫芦科瓜类作物遗传图谱构建、重要性状基因定位、遗传多样性及亲缘关系分析、分子标记辅助选择及在葫芦科遗传育种中的应用,对目前葫芦科遗传育种中应用分子标记技术存在的问题和解决方案进行了探讨,并对葫芦科分子标记辅助育种的前景做了展望。     

Microsporogenesis in Brachiaria brizantha (Poaceae) as a selection tool for breeding

The genus Brachiaria comprises more than 100 species and is the single most important genus of forage grass in the tropics. Brachiaria brizantha, widely used in Brazilian pastures for beef and dairy production, is native to tropical Africa. As a subsidy to the breeding program underway in Brazil, cytological studies were employed to determine the chromosome number and to evaluate microsporogenesis in 46 accessions of this species available at Embrapa Beef Cattle (Brazil). Thirty-four accessions presented 2n = 36; seven had 2n = 45, and five had 2n = 54 chromosomes. Based on the higher level of chromosome association observed in diakinesis, in tetra-, penta-, and hexavalents, respectively, it was concluded that they are derived from x = 9; consequently, these accessions are tetra- (2n = 4x = 36), penta- (2n = 5x = 45), and hexaploids (2n = 6x = 54). The most common meiotic abnormalities were irregular chromosome segregation due to polyploidy. Chromosome stickiness, abnormal cytokinesis, non-congressed bivalents in metaphase I and chromosomes in metaphase II, and chromosome elimination were recorded at varying frequencies in several accessions. The mean percentage of meiotic abnormalities ranged from 0.36 to 95.76%. All the abnormalities had the potential to affect pollen viability by generating unbalanced gametes. Among the accessions, only the tetraploid ones with less than 40% of abnormalities are suitable as pollen donors in intra- and interspecific crosses. Currently, accessions with a high level of ploidy (5 and 6n) cannot be used as male genitors in crosses because of the lack of sexual female genitors with the same levels of ploidy.     

Development and characterization of 41 novel EST-SSR markers for Pisum sativum (Leguminosae)

? Premise of the study: Expressed sequence tag (EST)-derived simple sequence repeat (SSR) markers were developed in Pisum sativum for further use in genetic studies and breeding programs. ? Methods and Results: Forty-one novel EST-SSR primers were developed and characterized for size polymorphism in 32 Pisum sativum individuals from four populations from China. In each population, the number of alleles per locus ranged from one to seven, with observed heterozygosity and expected heterozygosity ranging from 0 to 0.8889 and 0 to 0.8400, respectively. Furthermore, 53.7% of these markers could be transferred to the related species, Vicia faba. ? Conclusions: The developed markers have potential for application in the study of genetic diversity, germplasm appraisal, and marker-assisted breeding in pea and other legume species.