Isozyme polymorphism in Festuca rubraL.

Summary Six Festuca rubra populations from Europe and Scandinavia were studied for variation at three isozyme loci; phosphoglucoisomerase (PGI-2), glutamate oxaloacetate transaminase (GOT-3) and superoxide dismutase (SOD-1). Seven alleles were found at the Pgi-2 locus, four at the Got-3 locus and five at the Sod-1 locus. Most plants were heterozygous and up to five alleles were found in the same plant at the Pgi-2 locus. Each population could be distinguished by the presence or absence of certain alleles or by differences in the frequencies of the alleles present. Values for the Shannon diversity index were calculated which showed that there was considerable heterogeneity both within and between loci. In general, 53% of this diversity could be attributed to within population variation.     

大白菜-花椰菜异源多倍体的形态、细胞及分子鉴定

 应用形态学、解剖学、细胞学及分子标记的方法对大白菜与花椰菜的异源四倍体和异源三倍体进行倍性鉴定。结果表明,异源多倍体在植株叶片、花器官和气孔等性状上较其二倍体双亲均表现出巨大性,而气孔密度和结实率则降低,其中异源四倍体比异源三倍体表现更明显。SRAP 分子标记分析表明,异源多倍体中包含了双亲的遗传信息,是双亲间真杂种。细胞学观察显示,异源四倍体的染色体数为2n = 4x = 38,异源三倍体的染色体数为2n = 3x = 29。异源多倍体的获得及鉴定为进一步创制大白菜新种质提供了材料。     

Genetic identification of a newly synthetic allopolyploid strain with 206 chromosomes in polyploid gibel carp

A newly synthetic allopolyploid strain (SAS) was selected and established from gynogenetic offspring of gibel carp clone A⁺ with 156 chromosomes induced by common carp sperm with 50 chromosomes. In this study, the allopolyploid strain was detected to contain 206 chromosomes, and the growth trait was evaluated to have 25.15% growth faster than that of clone A⁺. Genetic marker analyses of transferrin (Tf) alleles, ITS1 sequences and mtDNA D‐loop sequences indicated that the allopolyploid strain was synthetized from maternal gibel carp clone A⁺ and paternal common carp, and the synthetic chromosome sets were further confirmed by genomic in situ hybridization (GISH) and chromosome localization of 45S rDNA. Significantly, the synthetic allopolyploid strain has tended to be stable by five successive generations of gynogenesis, because it still keeps unisexual reproduction mode of gynogenesis. Therefore, it will become a novel variety for gibel carp aquaculture in future.     

小麦族的基因组显性及其育种学意义

小麦族包含大量由不同基因组组成的异源多倍体物种。同一个异源多倍体物种的不同基因组可能对表型性状产生非对称性贡献,例如小麦属多倍体物种的形态分类特性,更像其A基因组供体物种,这种现象称为A基因组显性。由于基因组显性,小麦族形成了以A、D、U、St为轴心(显性)基因组的异源多倍体物种簇。异源多倍体物种的基因组显性可能与其进化适应优势的形成有关。在育种方面,基因组显性影响多倍体新作物开发及小麦-外源染色体易位设计。     

The inheritance of a basal branching type in guar

Summary Eight different genotypes of the F₁ hybrids between Oriental × Asiatic lily (Lilium) hybrids (2n = 2x = 24) were treated with nitrous oxide (N₂O) gas under pressure for 24 and 48 hours. At the time of treatment, all plants possessed early meiotic stages in the anthers of the oldest flower buds. The mature flowers from treated plants were monitored for fertility through pollen germination in vitro as well as by using them in crosses with diploid Asiatic hybrids (2n = 2x = 24) both as male and female parents. In five out of the eight genotypes of OA hybrids there was evidence for the production of 2n pollen which germinated in vitro from either one or both treatments. The 2n pollen from three genotypes was successfully used in crosses. In two cases, the treated plants were successfully used as female parents which indicated the formation of 2n (or 2x) egg cells. From an analysis of 41 sexual polyploid progenies obtained from N₂O treated plants it was shown that they were all euploids consisting of 34 triploids (2n = 3x = 36) and seven tetraploids (2n = 4x = 48). A detailed cytological analysis of 12 progeny plants through genomic in situ hybridization (GISH) proved that N₂O had induced first division restitution gametes in most cases and in two cases they produced gametes through indeterminate meiotic restitution. There was evidence for intergenomic recombination in three cases.     

Isozyme variation between diploid and tetraploid cytotypes of Glycine tabacina (Labill.) Benth.

Summary Glycine tabacina (Labill.) Benth. is a wild perennial species related to the cultivated soybean, G. max (L.) Merr. It is composed of diploid (2n=40) and tetraploid (2n=80) cytotypes. Currently, to differentiate the cytotypes, plants are grown out in the greenhouse and chromosome counts made on pollen mother cells. It is a laborious and time consuming process. The objective of this study was to determine whether electrophoretic techniques could be utilized to separate the cytotypes. Electrophoretic examination of seven isozyme systems from seed of 67 G. tabacina accessions revealed banding patterns that could be used to differentiate between diploid and tetraploid cytotypes in the species. Among the tetraploid accessions, the number of bands observed were always greater than the diploids. Some tetraploid banding patterns consisted of bands similar to the diploid tabacina and/or additional bands previously identified in other Glycine species. The patterns of isozyme multiplicity and variation in the tetraploid tabacinas suggests more than one mode of origin for the tetraploids.     

黄瓜与酸黄瓜异源多倍体3种同工酶表达基因组剂量效应

 以甜瓜属（Cucumis）黄瓜与酸黄瓜的3种不同倍性异源多倍体 - 双单倍体种间杂种F₁（2n = 2x = 19,HC）、异源三倍体黄瓜（2n = 3x = 26,HCC）和异源四倍体C. hytivus (2n = 4x = 38,HHCC)及其双亲为试材,比较研究过氧化物酶（POD）、谷氨酸脱氢酶（GDH）和天冬氨酸转氨酶（AAT）在不同倍性异源多倍体中的酶谱表达特性,探讨基因组剂量对酶谱表达的影响。结果表明：不同倍性异源多倍体的酶带染色力表现出明显的差异,但酶带数和酶带分布基本一致。在AAT同工酶中,酶带的表达随基因组剂量的提高而增强,在POD和GDH同工酶中,大部分酶带的表达随基因组剂量的提高而减弱。这些结果表明甜瓜属异源多倍体在不同的酶系统中,酶谱表达可能会表现出截然相反的基因组剂量效应。本研究结果可为     

The successful transfer of primocane fruiting expression from raspberry to Rubus hybrid berry

This paper describes the successful transfer of the primocane fruiting (PF) character from raspberry (Rubus idaeus) to Rubus hybrid berries following crosses between raspberry and blackberry. The transfer was achieved by doubling the chromosome complement of PF raspberry selections in culture using colchicine, and using regenerant tetraploid PF plants as the female parents in crosses with tetraploid or octoploid blackberries, or with hexaploid hybrid berries (all summer fruiting). The results show that the PF character is expressed more readily in hybrid plants where at least 50% of the chromosomes in the hybrid genome are derived from raspberry. In vitro germination of cut seeds overcame the poor germination often encountered in Rubus and ensured the rapid recovery of hybrid seedlings. This revised version was published online in July 2006 with corrections to the Cover Date.     

基因组位点对引物的竞争效应

采用RAPD标记研究黄瓜属 (CucumisL .)正反杂交及不同倍性杂种的差异 ,发现在筛选的 76条引物中 ,有 2 1条(占 2 7 6 % )发生亲本条带的缺失。从缺失的位点数来看 ,亲本酸黄瓜 (C .hystrixChakr.2n =2 4 )在杂种中缺失的比例为 5 1%～ 6 9% ,亲本栽培黄瓜 (C .sativusL . 2n =14 )为 5 7%～ 9 8%。所有杂种扩增出的条带数要远小于理论值 ,这可能是由于两种基因组间位点对引物的竞争所致。正反杂交对扩增也有较大影响 ,其中 11条引物 (占 14 5 % )在正反杂种间存在较大差异 ,部分引物条带呈“父性”扩增的规律 ,但这部分条带仍是核基因组上的位点。通过对总基因组DNA和叶绿体DNA扩增结果的深入研究 ,表明核基因组DNA和叶绿体DNA之间亦存在位点对引物的竞争效应。