Hybridization between Viola canina and V. persicifolia in Norway

Hybridization in Norway between Viola canina and V persicifolia was investigated by analysis of root tip mitosis, pollen stainability and morphological variation. The chromosome number was proved to be 2n = 40 (tetraploid) for V. canina ssp. montana , 2n = 20 (diploid) for V. persicifolia and 2n = 30 (triploid) for the hybrid, V. canina × persicifolia . No deviating chromosome numbers were found. The tetraploids and the diploids had a high frequency, and the triploids a low frequency, of apparently good pollen grains. Canonical variate analysis were used to investigate the pattern of morphological differentiation in the material. The specimens clearly separate into three groups in accordance with the three ploidy levels. No introgression was demonstrated.     

远缘杂交和异源多倍体化技术在水稻育种中的应用

从野生稻遗传资源在育种中的作用出发,概述了栽培稻与野生稻远缘杂交和多倍体化在水稻育种中的应用。对远缘杂交中的杂交不亲和性以及杂种不育等问题采用激素处理、胚挽救等途径解决,对所获杂种从形态学、细胞学、生物化学以及分子生物学等多方面鉴定,对栽野杂种存在的野生性状通过选择与改造相结合的方法而淘汰,对其有利基因则加以选择和聚合以获得稳定优良品种。这些从理论上和实践上证明远缘杂交和多倍体化相结合的异源多倍体化是获得高产优质水稻新品种的一条新途径。     

作物远缘杂交育种的途径及其实质

作物远缘杂交的育种可操作性及效果多年来颇有争议,科学家对物种起源与进化的研究恰恰是指导作物远缘杂交育种的理论基础。物种形成理论研究表明生命的共同起源是远缘杂交的理论基础,生物多样性是远缘杂交的物质基础。生物种间的繁殖隔离机制是远缘杂交不亲和性障碍的根源所在,而物种形成方式又为克服远缘杂交的不亲和性提供了理论依据。其中异域性物种形成方式下的生殖隔离具有不彻底性,是克服远缘杂交受精前不亲和性的理论根据;同域性物种形成方式中多倍体化的方式对远缘杂交受精后不亲和性的克服具有较强的指导意义。本文在通过对以上方面的阐述,剖析了远缘杂交的障碍来源、克服途径及实质,为作物远缘杂交育种工作提供参考。     

体细胞杂交技术在蔬菜育种中的研究与应用

从创造蔬菜新种质,丰富蔬菜种质资源;转移和创造CMS性状;蔬菜抗病、抗虫、抗逆育种;改变蔬菜生理类型等四方面详细介绍了体细胞杂交技术在蔬菜育种上的应用。并对体细胞杂交的主要优缺点及其注意事项进行了分析讨论。     

国兰新品种的选育和杂交育种研究进展

国兰是中国的传统名花。目前,国兰通常被认为包括墨兰、建兰、春兰、蕙兰、寒兰、莲瓣兰和春剑七种,共有数千个品种。至2010年12月31日止,在英国皇家园艺学会(RHS)登录的以国兰为直接亲本的杂交种已达227个。国兰在我国已有2 500多年的栽培历史,但我国大陆在国兰杂交育种方面研究于20世纪70年代才开始且进展缓慢。杂交国兰由于超亲的生长优势、丰富的花色花姿,清香的气味而具有广阔的应用前景。本文对我国国兰新品种选育和杂交育种的现状进行了综述,提出了我国国兰杂交育种的方向。     

Hybridization of cultivated Vitis vinifera with wild V. californica and V. girdiana in California

Hybridization of introduced domesticates and closely related natives is well documented in annual crops. The widespread introduction of the domesticated grapevine, Vitis vinifera, into California where it overlaps with two native congenerics, with which it is interfertile, provides opportunity to investigate hybridization between woody perennials. Although geographically widespread, the introduction over the past two centuries has been limited to a few elite clonal cultivars, providing a unique opportunity to study the effects of hybridization on the native species. The amount of hybridization with V. vinifera and the genetic diversity of wild‐growing Vitis californica and Vitis girdiana were examined using nineteen microsatellite markers. STRUCTURE analysis was used to define hybrid and introgressed individuals and to analyze genetic structure of the native species. FAMOZ software was used to identify which V. vinifera cultivars served as parents of F₁ hybrids. The three species were clearly distinguished by STRUCTURE analysis. Thirty percent of 119 V. californica vines were hybrids. The domesticated parent was identified for 16 F₁ hybrid vines; the original California cultivar, ‘Mission’, was the parent of eight. Backcrosses were also found, showing introgression into subsequent generations. Similar results were obtained for a small sample of V. girdiana. Removing hybrids greatly reduced the genetic variation of the presumed pure species, among which there was essentially no genetic structure. Limited genetic variability indicates the California natives may be threatened by genetic erosion. The discovery of F₁ hybrids of ‘Mission’, a cultivar not grown in the areas for ~100 years, suggests long generation times for wild vines that, often, grow into expansive liana and propagate by layering, all factors that limit recruitment in populations already disjunct by habitat lose. Hermaphroditic flowers and fruit that is more attractive to birds may favor the production of backcross seed and establishment of introgressed individuals.     

原位杂交技术在植物遗传育种上的应用

本文在简要介绍原位杂交技术的基础之上,重点介绍了该技术在植物遗传育种领域,即在(1)异源染色质及染色体畸变检测;(2)植物基因工程及基因表达研究;(3)构建植物基因物理图谱;(4)染色体RNA研究等方面的应用现状,并对原位杂交技术在提高检出率,与染色体显带技术结合,PCR-原位杂交等方面提了一些见解。     

原位杂交技术在植物遗传育种上的应用

本文在简要介绍原位杂交技术的基础之上 ,重点介绍了该技术在植物遗传育种领域 ,即在 (1 )异源染色质及染色体畸变检测 ;(2 )植物基因工程及基因表达研究 ;(3)构建植物基因物理图谱 ;(4)染色体RNA研究等方面的应用现状 ,并对原位杂交技术在提高检出率 ,与染色体显带技术结合 ,PCR 原位杂交等方面提了一些见解。     

Breeding of high ergosterol-producing yeast strains

High ergosterol-producing yeast strains YEH-28 and YEH-56 were constructed by hybridization of two haploids with opposite mating types from different species. The fermentation conditions of hybrid strain YEH-56 were studied. The highest level of ergosterol was obtained in 30 h at 28°C and 200 rpm, when 60 ml of culture in 250-ml shake flasks was grown in fermentation medium that consisted of (per liter): 100 g glucose; 10 g peptone and 10 g yeast extract. The initial pH was adjusted to 6.0. The optimal inoculum volume was 10% (v/v). Under optimal conditions, the yield of ergosterol of YEH-28 strain is 1.96 and 1.56 times that of the parental strains YE39 and YE244, whereas that of YEH-56 is 1.98 and 1.57 times that of the parental strains YE39 and YE244, respectively. Analysis of genetic stability showed that hybrid strains YEH-28 and YEH-56 are stable genetically. Journal of Industrial Microbiology & Biotechnology (2000) 25, 39–44. Received 13 November 1999/ Accepted in revised form 09 March 2000     

Hybridization and selection for improving seed protein in barley

Summary Hybridization followed by continuous selection of lines of barley from different cross-combinations involving high protein-high lysine genotypes and the agronomically superior strains resulted in breaking the negative correlations between 1000 grain weight and high protein content and high DBC values. The methodology of DBC-Kjeldahl protein adopted in the present study is likely to be useful in identifying high lysine lines. The present study has shown considerable variability with respect to protein content and grain weight and has provided interesting genotypes which can be used in synthesising lines with improved nutritional quality and productivity in barley. The success in breaking the undesirable linkages to factors that impair the endosperm development is due to sufficient genetic variability in the initial breeding material as well as the use of suitable breeding procedures like the full-sib mating in the early segregating generations.     

Genetic selection of meiotic and mitotic recombinant yeast artificial chromosomes.

We have developed a genetic screen for the isolation of larger or smaller recombinant yeast artificial chromosomes derived from overlapping YACs. Integration plasmids were used to modify the TRP1 and URA3 auxotrophic markers present respectively on the left and right vector arms of one of the parental YACs. Diploids containing the two parental YACs were studied through meiosis and mitosis. Tetrad analysis revealed the presence of meiotic recombinant YACs at a frequency comparable with what is expected for yeast DNA (about 3 kb/cM). More direct genetic selection of diploids on -TRP-LYS synthetic media in the presence of 5-fluoro-orotic acid (5-FOA), led to the isolation of mitotic recombinant YACs at a high frequency. Analysis of these yeast cells by pulsed-field gel electrophoresis, confirmed the loss of both parental artificial chromosomes, and the specific retention of a larger or smaller recombinant YAC.