Studying Genetic Diversity in Inbred Sunflower Lines by RAPD and Isozyme Analyses

Genetic diversity of 30 inbred sunflower lines was examined by RAPD and isozyme analyses. The inbred lines were shown to be highly polymorphic by RAPD markers. The line distribution on genetic similarity dendrograms based on the RAPD and isozyme data was analyzed. High effectiveness of RAPD analysis for differentiating genotypes of inbred sunflower lines was demonstrated.     

Analysis of linkage between genes controlling enzymes in sunflower

The polymorphism of leucine aminopeptidase in 23 inbred lines of sunflower of mutant origin was studied. The isozyme spectrum of leucine aminopeptidase is presented as a single zone of enzyme activity controlled by one gene. This gene was shown to be inherited independently from genes of esterase and 6-phosphogluconate dehydrogenase.     

Analysis of linkage between genes controlling enzymes in sunflower

The polymorphism of leucine aminopeptidase in 23 inbred lines of sunflower of mutant origin was studied. The isozyme spectrum of leucine aminopeptidase is presented as a single zone of enzyme activity controlled by one gene. This gene was shown to be inherited independently from genes of esterase and 6-phosphogluconate dehydrogenase.     

RAPD analysis of seed purity in a commercial hybrid cabbage (Brassica oleracea var. capitata) cultivar.

The use of random amplified polymorphic DNA (RAPD) markers for evaluating seed purity in a commercial F1-hybrid cabbage (Brassica oleracea var. capitata) cultivar is demonstrated. Genomic DNA isolated from single ungerminated seed was found to be suitable for RAPD analysis. DNA from F1-hybrid and its parental lines was subjected to RAPD screening with 36 random decamer arbitrary primers. A total of 241 scorable products were observed with 54 (22%) being polymorphic. The RAPD data showed that the parental lines of this commercial cabbage cultivar were not very closely related. Two primers were chosen for purity testing of the F1-hybrid seeds. The sib (inbred seed; seed from self-pollination of parental lines) contamination results obtained by RAPD analysis were comparable to the commonly used grow-out trial and isozyme analysis, hence showing that RAPD analysis can be used for seed purity testing of commercial hybrid cabbage seeds.     

Variation of Storage Proteins and Isozymes within Maize Inbred Lines

Seed storage proteins of ten maize inbred lines were investigated by sodium dodecyl sulfate polyacrylamide gel electrophoresis. In addition, fourteen isozyme loci representing nine isozyme systems were analysed. Salt-soluble protein fraction contained a large number of proteins (30 – 40 bands) of different sizes with genotypic differences among the ten inbred lines. The methionine-rich 10 kD zein showed differential expression in the ten inbred lines with different migration rates on the SDS-PAGE. This polypeptide was completely absent in the inbred line G221D. Among nine of the inbred lines, eight of 14 isozyme loci were polymorphic and six were monomorphic resulting in seven unique fingerprints.     

Polymorphism and genetic control of some isozyme systems in mutant sunflower lines

Polymorphism of six isozyme systems (ME, EST, 6-PGD, AAT, ACP, IDH) of sunflower mutant inbred lines has been studied. It was shown that only three of them were polymorphic (ME, EST, 6-PGD). Two isoforms were observed for each polymorphic enzymic zone. Genetic control of malic-enzyme has been studied and it was determined that the identified polymorphic zone of the enzyme was controlled by one gene. The genes of malic-enzyme synthesis, anodal esterase and 6-phosphogluconat-dehydrogenase are inherited independently.     

Genetic diversity of inbred rye lines evaluated by RAPD analysis

This study presents an attempt to supply breeders of hybrid rye with more genetic information on inbred lines, using molecular markers. Eighteen polymorphic loci detected by means of the RAPD (Random Amplified Polymorphic DNA) technique and mapped on 2R-7R rye chromosomes, were applied to study genetic similarities among forty inbred lines of rye. The lines were grouped in four main clusters revealed on dendrogram, which was generally consistent with the pedigree data. Mapped RAPD markers were shown to be a useful tool for phenetic studies in rye. Additionally, a system of 20 polymorphic fragments, detected by three primers, was developed for fingerprinting of rye lines. The system of RAPD markers, which was developed in this study, should be helpful in characterisation of rye genetic stocks used for breeding.     

陆地棉×比克氏棉育成种质系的同工酶和RAPD分析

为了从分子水平上检验野生棉遗传特性向陆地棉转育的结果以及育成种质之间的遗传差异,通过等电聚焦电泳和RAPD技术,对来自科遗181陆地棉品系与野生比克氏棉杂交后代的6个遗传稳定的不同种质系及其亲本的过氧化物酶同工酶图谱和DNA指纹图谱进行了分析。结果如下（1）6个种质系的基本酶谱特征均倾向于陆地棉亲本,但在其中2个种质系的过氧化物酶图谱中,观察到各具有1条等电点值（PI）为4.85的野生亲本的特征带;（2）DNA指纹图谱的分析表明,不同种质系之间在基因组水平上具有高度的异质性。并且在OPO10和OPO112个引物的扩增图谱中观察到4个育成种质系具有野生比克氏棉亲本的特征带。     

RAPD技术在黑糯玉米亲缘关系划分上的应用

以8个黑糯玉米自交系为试验材料,利用CTAB微量提取法从幼苗中提取DNA,进行RAPD扩增,筛选出3个能产生稳定遗传多态性的引物,分别是OP—A01、OP—A11和OP-006;利用这些引物的扩增出的指纹图谱,进行聚类分析,可将8个自交系划分为4个类群,与各个自交系的来源基本一致。表明RAPD可以用于黑糯玉米亲缘关系的划分。     

RAPD技术在玉米自交系亲缘关系研究中的应用

通过对我国正在使用的１２个玉米骨干自交系的ＲＡＰＤ分析,从２２０个Ｏｐｅｒｏｎ引物中筛选出１２个能产生稳定的遗传多态性的引物,利用这些引物扩增出的指纹图谱,进行聚类分析,可将全部供试自交系分成３个类群,第１类群包括黄早４系统的５个自交系;第２类群包括４７８和４８８两个姊妹系;第３类群包括５个关系较远的自交系,其中３个来自美国,１个是全部中国血统,１个既有美国血统又有中国血统。这个结果与根据各个自交     

Genomic instability in sunflower interspecific hybrids

The expression of genomic instability was studied at the phenotypical (morphological characters, electrophoretic spectra of seed storage proteins) and molecular (DNA amplification products) levels in interspecific hybrids (ISHs) from crosses of inbred lines of cultivated sunflower Helianthus annuus with perennial species of the genus Helianthus and in introgressive lines (ILs) produced on their basis. Unstable state of the locus determining the trait of lower branching was proved by the method of hybridological analysis. It was shown with the use of RAPD markers that the IL genome is characterized by instability even after long-term inbreeding (in generations F₈-F₁₂). In progenies of different combinations of interspecific crosses, identical polymorphic variants were revealed for a seed storage protein, helianthinin, and for DNA fragments homologous to structural genes of functionally important proteins, suggesting the nonrandom character of ISH genome variation. This variation may be determined by genome reorganizations under the action of a genome shock induced by interspecific hybridization. The factors inducing reorganizations in the genome include the activity of mobile genetic elements (MGEs). Using primers specific to different MGE families, nucleotide sequences with a high level of homology to the sequences of fragments of the mobile elements MuDR, Far1, CACTA, Stowaway, and Tourist were identified in the sunflower genome. The possibility of using MGE fragments for sunflower genotyping was demonstrated.     

A Method to Measure Aggressiveness of Plasmopara halstedii (Sunflower Downy Mildew)

For the first time, a method was used to measure aggressiveness of two Plasmopara halstedii races (100 and 710), the parasite causing sunflower downy mildew. Two sunflower lines showing different levels of quantitative resistance were used to measure two aggressiveness criteria: latent period and sporulation density. A strain of race 100 had a shorter latent period and greater sporulation density than a strain of race 710. The sunflower inbred line BT, rather susceptible in the field, presented a greater sporulation density and a shorter latent period than another inbred line FU, which shows greater resistance in the field. These results indicated that race 100 was more aggressive than race 710. The behaviour in the field of the two inbred lines was confirmed in the laboratory observations.     

Diversity Among a Heterodera glycines Field Isolate and Derived Inbreds Based on RAPD Analysis and Reproduction on Soybean Genotypes

A field population of Heterodera glycines was inbred by a combination of controlled male-female matings and inoculation of soybean with second-stage juveniles (J2) from single cysts. The initial and four F₆ inbred populations were subjected to random amplified polymorphic DNA analysis and were also tested for their ability to reproduce on race differentials. The RAPD patterns of the inbred populations had a lower number of total bands and a lower percentage of polymorphic bands among individual cysts than the initial population. The estimated number of polymorphic loci detected by RAPD analysis was about 25% for the initial population and 4% to 7% for the inbred lines. Reproduction of H. glycines decreased for 6 of 24 inbred-soybean combinations. In particular, reproduction of three inbred populations on PI 90763 was greatly reduced. Inbreeding did not decrease variance of cyst number on soybean genotypes. The inbreeding coefficient calculated from RAPD data was greater than that derived from the known inbreeding pedigree.     

Mapping Three Classical Isozyme Loci in Tetrahymena: Meiotic Linkage of Esta to the Chxa Linkage Group

We demonstrate a reliable method for mapping conventional loci and obtaining meiotic linkage data for the ciliated protozoan Tetrahymena thermophila. By coupling nullisomic deletion mapping with meiotic linkage mapping, loci known to be located on a particular chromosome or chromosome arm can be tested for recombination. This approach has been used to map three isozyme loci, EstA (Esterase A), EstB (Esterase B), and AcpA (Acid Phosphatase A), with respect to the ChxA locus (cycloheximide resistance) and 11 RAPDs (randomly amplified polymorphic DNAs). To assign isozyme loci to chromosomes, clones of inbred strains C3 or C2 were crossed to inbred strain B nullisomics. EstA, EstB and AcpA were mapped to chromosomes 1R, 3L and 3R, respectively. To test EstA and AcpA for linkage to known RAPD loci on their respective chromosomes, a panel of Round II (genomic exclusion) segregants from a B/C3 heterozygote was used. Using the MAPMAKER program, EstA was assigned to the ChxA linkage group on chromosome 1R, and a detailed map was constructed that includes 10 RAPDs. AcpA (on 3R), while unlinked to all the RAPDs assigned to chromosome 3 by nullisomic mapping, does show linkage to a RAPD not yet assignable to chromosomes by nullisomic mapping.     

Combined mapping of DALP and AFLP markers in cultivated sunflower using F9 recombinant inbred lines

A genetic map was constructed with specific PCRs, DALPs and AFLPs using F8-generation sunflower recombinant inbred lines. RI lines generated from a F2 population of one cross between the two cultivated inbred lines HA89 (maintainer for Pet1 CMS) and LR4 (restorer for Pet1 CMS) were used. A total of 305 markers were located using seven sPCR, 64 DALP and 301 AFLP loci. They were generated with one, seven and 14 primer pairs, respectively. The map construction consisted of a two-step strategy using 6 and 3.1 LOD scores revealed by a simulation file. Mapped markers were assembled into 18 linkage groups covering 2,168.6 cM with an average of 6.1 cM. The distribution of DALPs and AFLPs revealed that both markers tagged different regions to enable covering most of the sunflower genome. This leads to the longest map published so far for sunflower.     

Random amplified polymorphic DNA and pedigree relationships in spring barley

Summary We investigated random amplified polymorphic DNA (RAPD) in 27 inbred barley lines with varying amounts of common ancestry and in 20 doubled-haploid (DH) lines from a biparental cross. Of 33 arbitrary 10 base primers that were tested, 19 distinguished a total of 31 polymorphisms. All polymorphisms were scored as dominant genetic markers except for 1, where Southern analysis indicated the presence of two codominant amplification products. The inheritance of 19 RAPD polymorphisms and one morphological trait was studied in the DH lines. There was no evidence for segregation distortion, but a group of four tightly linked loci was detected. The frequencies of RAPD polymorphism in pairs of inbred lines were used to compute values of genetic distance (d), which were compared to kinship coefficients (r) between the same pairs of lines. A linear relationship between r and d was evident, but low values of r gave poor predictions of d. Cluster analysis showed that groups of inbred lines based on r were similar to those based on d with some notable exceptions. RAPD markers can be used to gain information about genetic similarities or differences that are not evident from pedigree information.     

Identification and validation of breeder-friendly DNA markers for Pl arg gene in sunflower

Downy mildew is a fungal disease of sunflower that can lead to severe yield losses. The damage caused by the pathogen can be controlled by growing resistant sunflower varieties. Gene Pl _arg was introgressed into cultivated sunflower from the wild species Helianthus argophyllus and provides resistance against all known downy mildew races. In this study, we used a mapping population from the cross-RHA 419/RHA-N-49. We identified a new co-segregating simple sequence repeat marker ORS675 and confirmed the co-segregation of markers ORS716 and ORS662 with Pl _arg gene. The markers were validated on two registered resistant inbred lines RHA 443 and RHA 464, as well as on twenty inbred lines RH 1–20 obtained through methods of classical breeding. Molecular marker ORS716 was assessed for usefulness in selecting resistant progeny in 12 BC populations. Markers were found to be valuable for molecular breeding in diverse genetic backgrounds and enabled transfer of the resistance gene in different sunflower genotypes.     

利用分子标记技术检测玉米杂种纯度研究

以12份玉米自交系及其组配的8个杂交种为材料,利用分子标记技术进行杂种纯度检测研究。有用RAPD标记方法,从300个随机引物中,筛选确定了8个杂交种种子纯度检测引物,制定了检测标准标记图谱。建立了海禾3纯度分析的SCAR标记,该SCAR标记与RAPD标记在种子纯度检测上结果完全一致。     

RAPD在三色堇（Viola wittrockiana）自交系遗传关系研究及杂种优势预测中的应用

用RAPD技术分析了18个三色堇(Viola wittrockiana)自交系的遗传多样性。21个随机引物扩增了167条带,其中127条具多态性,显示自交系间存在较大的遗传变异。用UPGMA法可将自交系聚为五大类,其分类结果与花径和材料来源地基本一致。以其中的5个自交系进行双列杂交试验,研究了RAPD遗传距离与三色堇杂交后代10个性状杂种优势的关系,实验结果表明:RAPD遗传距离仅与花数达到0.1的显著水平,而与其它8个性状杂种优势的相关性不显著;用RPAD遗传距离预测三色堇的花数杂种优势具有一定的可靠性,但用于对其它性状杂种优势的预测目前是不可行的。