Authors:J. C. Reif, S. Hamrit, and A. E. Melchinger
It has been claimed that the system that delivers the products of plant breeding reduces the diversity of cultivated varieties, leading to increased genetic vulnerability. The objective of our study was to monitor the temporal trends in genetic diversity over the past five decades among maize cultivars with the largest acreage in Central Europe. Thirty individuals of five prominent open-pollinated varieties (OPVs) from Central Europe, 85 maize hybrids of economic importance, and their dent and flint parental components were examined with 55 SSRs. The genetic variation within and among varieties decreased significantly during the five decades. The five OPVs contain numerous unique alleles that were absent from the elite flint pool. Consequently, OPVs could represent useful sources for broadening the genetic base of elite maize breeding germplasm.
Authors:K. Wajdzik, G. Gołębiowska, M. Dyda, K. Gawrońska, M. Rapacz, and M. Wędzony
The increasing economic importance of triticale (×Triticosecale Wittm.) makes this synthetic hybrid cereal an interesting object of genetic studies. Genomic regions (QTL) of morphological winter triticale traits were determined using the mapping population of 89 doubled haploids lines (DHs) developed from F1 hybrid of cv. ‘Hewo’ and cv. ‘Magnat’ accompanied with the genetic map consisting of 20 linkage groups assigned to the A (7), B (7), and R (6) genomes (total of 3539 DArT, SNP-DArT and SSR markers, length of 4997.4 cM). Five independent experiments were performed in the field and greenhouse controlled conditions. A total of 12 major QTLs located on 2B, 5A, 5R, and 6B chromosomes connected to the stem length, the plant height, the spike length, the number of the productive spikelets per spike, the number of grains per spike, and the thousand kernel weight were identified by a composite interval mapping (CIM).
Authors:D. Obreht, B. Kobiljski, S. Denčić, M. Djan, and Lj. Vapa
Implementation of marker assisted selection (MAS) in conventional breeding programs could allow assessment of the genetic potential of specific genotypes prior to their phenotypic evaluation. Furthermore, it could identify important trait alleles or marker-trait associations for further determination of a precise position for the loci of interest. Potential uses of microsatellite markers in molecular evaluation of bread-making quality was tested in a sample of 69 wheat genotypes that were genotyped with 3 microsatellites linked to previously mapped QTLs for loaf volume and Hagberg falling number on chromosome 3A. A total of 19 alleles were found, with an average of 6.33 alleles per loci, and average PIC value of 0.40. Specific SSR alleles were tested for association with bread-making related parameters. The association study approach, which uses statistical analysis of marker and phenotypic data, showed significant association of a specific allele at the GWM674 locus with Hagberg falling number in wheat.
Authors:V. Nikashina, V. Tyurina, M. Senjavin, G. Stefanov, G. Gradev, I. Stefanova, and A. Avramova
The ion-exchange equilibrium of cesium and strontium ions on clinoptilolites from different deposits — Dzegvi and Tedzami /Georgian SSR/, Beli Plast and Beli Bair /Bulgaria/ in different cationic forms of the sorbents /natural, sodium, calcium and ammonium/ is studied. The static ion-exchange capacities are determined. The sorption isotherms are plotted and the corresponding distribution coefficients are calculated. Mechanical characteristics which are important for the assessment of the technological use of the sorbents in dynamic conditions are determined. The clinoptilolite from Beli Plast deposit has the highest capacity in comparison with the other studied zeolites. The selectivity of the clinoptilolites from Bulgarian deposits is independent of the cationic form of the sorbent while the selectivity of the Georgian clinoptilolites strongly depends on the cationic form; the selectivity of the ammonium form of Tedzami sorbent is the highest.
Authors:V. Sokolsky, V. Solodukhin, and V. Smetannikov
The applicability of instrumental activation analysis by the conversion radiation of impurities in matrices with high specific
gamma-activity has been studied. An iron-free toroidal magnetic β-spectrometer with 2 per cent resolution and 20 per cent
transmission for 4 was used for measurement. The spectrometer was made at the Activation Analysis Laboratory of the Academy
of Sciences of the Kazakh SSR. Comparative gamma- and beta-spectra of samples of amorphous selenium thin films with palladium,
cadmium, indium and mercury impurities were obtained. It was established that the analysis by the spectra of internal conversion
electrons enables to increase the detection sensitivity of these elements in selenium as compared to the gamma-spectrometric
method. The procedure of mercury determination in amorphous selenium films was developed and by this method the investigation
of the dependence of photoconductive properties of the film upon the total mercury content and its distribution on the film
surface was carried out.
Authors:T. Harangozó, Gy. Pernesz, A. Veres, K. Tóth-Lencsés, L. Heszky, and E. Kiss
The aim of this paper was to find possible link between molecular and morphological similarities of 38 Hungarian white grape varieties. Three aspects of morphological and molecular similarity were assessed in the study: comparison of the ordered variety pairs, assessment of molecular and morphological mean similarity differences and separation of varieties into similar groups by divisive cluster analysis to define (DIANA). Molecular similarity was calculated from binary data based on allele sizes obtained in DNA analysis. DNA fingerprints were determined at 9 SSR loci recommended by the European GrapeGen06 project. Morphological similarity was calculated on the basis of quantitative morphological descriptors. Morphological and molecular similarity values were ordered and categorized after pairwise comparison. Overall correlation was found to be weak but case by case assessment of the variety pairs confirmed some coincidence of molecular and morphological similarity. General similarity position of each variety was characterized by Mean Similarity Index (MSI). It was calculated as the mean of n-1 pair similarity values of the variety concerned. Varieties were ordered and compared by the difference of the index. Five varieties had low morphological and high molecular MSI meaning that they share several SSR marker alleles with the others but seems relatively distinct according to the expression of their morphological traits. Divisive cluster analysis was carried out to find similar groups. Eight and twelve cluster solutions proved to be sufficient to distinct varieties. Morphological and molecular similarity groups partly coincided according to the results. Several clusters reflected parent offspring relations but molecular clustering gave more realistic results concerning pedigree.
Authors:G. Arafayne, A. Menkir, V.O. Adetimirin, and M. Gedil
Molecular-based characterization of open-pollinated varieties (OPVs) in maize is useful to define their unique profiles. A total of 58 SSR markers selected from a panel of 70 were used for genotyping three samples of 30, 50 and 100 plant bulks for each of 32 OPVs. The SSR markers detected a total of 253 alleles in the 32 maize OPVs across the three bulk samples. The number of alleles per marker varied from 2 to 7, with an overall mean of 4.36. The genetic distance among the OPVs varied from 0.17 to 0.93 with an average of 0.70 ± 0.007 for bulk samples of 30 plants, 0.20 to 0.91 with an overall mean of 0.70 ± 0.007 for bulk samples of 50 plants and from 0.30 to 0.95 with an average of 0.75 ± 0.006 for bulk samples of 100 plants. Cluster analysis separated the 32 maize OPVs into two major groups, which were further separated into two sub-groups for each type of bulk sample. The groupings of the OPVs into two major groups and their corresponding sub-groups was consistent with known breeding history (common parentage) and common target traits during development of the OPVs irrespective of the sample size used. However, in the bulk samples of 50 and 100 plants, some sub-groups were composed of OPVs with mixed maturity classes and diverse genetic backgrounds. Of the three independent bulk samples, the smallest sample size of 30 plants was found to be optimal for characterizing heterogeneous and heterozygous maize populations and OPVs owing to its cost-effectiveness and relative ease of sample processing.