No description available.

No description available.

No description available.

No description available.

Starch gel electrophoresis and isoenzyme staining were studied in raspberry (Rubus idaeus L., R. X neglectus Peck, and R. occidentalis L.). Seven isoenzymes could be separated using one of two gel-electrophoresis buffers: tris-citric acid at pH 7.1 for aconitase (ACO), isocitrate dehydrogenase (IDH), phosphoglucomutase (PGM), and triose phosphate isomerase (TPI) and histidine-citric acid at pH 5.7 for malate dehydrogenase (MDH), phosphoglucoisomerase (PGI), and shikimate dehydrogenase (SKDH). There were no variations detected between samples obtained from micropropagated shoots, greenhouse-, or field-grown plants. Tissue type and age had no effect on isoenzyme banding patterns except for PGM where this affected the relative densities of the bands. Fifty-five out of 78 raspberry cultivars could be uniquely characterized using the above isoenzymes. Analysis of cultivars obtained from multiple sources detected occasional mislabelled plants. The mode of inheritance of raspberry isoenzymes was studied and analysis of co-segregating loci revealed two possible linkage groups: Mdh-2/Tpi-2/Pgm-1 and Idh-1/widh. / A high rate (70%) of adventitious shoot regeneration was observed from leaf-petiole explants of micropropagated shoot cultures of 'Comet' red raspberry cultured on modified Murashige-Skoog medium containing 1 mg/l thidiazuron (TDZ) and 0.5 mg/l 1H-indole-3-butanoic acid (IBA). Variation in the agar concentration or incubation temperature, orientation or scoring of the leaf-petiole explants and use of separate leaf or petiole explants had no effect on shoot regeneration while incubation in the dark for 1, 2, or 3 weeks prior to growth in the light depressed the number of adventitious shoots formed. Only 8 of 22 raspberry cultivars were capable of regenerating from leaf explants of greenhouse-grown plants.

Certain types of infertility found in various animal populations may be due to genetic causes. This type of lowered reproduction becomes increasingly important in the male as the use of artificial insemination extends to more species. The extensive use of affected males tends to increase the frequency of these deleterious alleles in a population and thus lower the rate of reproduction of the species. In poultry, poor reproductive performance is a commercially important problem in broiler and turkey production. Any information, either genetic or physiological in nature, which might help correct this problem should be met with prompt attention. / fr

Impatiens walleriana Hook.f. is a popular bedding plant with a variety of flower colours excepting yellow. Transfer of this characteristic could be achieved through somatic hybridization, thus this study was an attempt to establish the basic parameters of tissue and protoplast culture. The condition of the stock plants and surface sterilisation techniques are important for this species. Most tissues responded to trials for callus induction with rhizogenesis. Evaluation of media and plant growth regulator combinations revealed that axillary shoot proliferation was most efficient on MS medium with 3.0 mg/L BAP and 0.1 mg/L IBA. Protoplast isolation was most effective in 0.5% w/v cellulase and 0.25% w/v pectinase with 0.25 M mannitol and 0.25 M glucose yielding 2.70 $ times$ 10$ sp5$ protoplasts per gram of leaf tissue. The presence of mucous, raphids and excessive debris inhibited successful culture of leaf mesophyll protoplasts. Cotyledon protoplasts show promise for such investigations.

Septoria tritici blotch (Stb) is a major foliar disease of wheat worldwide caused by the fungal pathogen Mycosphaerella graminicola. This project mapped the chromosomal locations of Stb resistance, which will be useful for wheat cultivar enhancement. In the first study of this project, Stb resistance and grain yield quantitative trait loci (QTL) were identified in a winter wheat doubled-haploid (DH) population produced from the cultivars Pastiche (resistant) and Torfrida (susceptible). A genetic map of the population was constructed using 104 microsatellite and 202 DArT markers. Separate disease and yield field trials were conducted in north-western Europe to measure natural Stb infection and grain yield, respectively. A resistance QTL from Pastiche was identified (QStb.jic-2A) that reduced flag leaf pycnidial density by 31.2% compared to the population mean. A second QTL from Pastiche (QYld.jic-2A) co-localized with QStb.jic-2A, and conferred an increase in grain yield of approximately 2.0% (0.19 t ha-1). The second study determined the map location of the third multiple-isolate resistance gene in the hexaploid landrace Salamouni. A population was developed using the resistant DH line 98S05B*13 (Salamouni/Katepwa) crossed to the susceptible cultivar Katepwa. The parent 98S05B*13 was found to contain the resistance gene Stb14 on chromosome 3BS, therefore, to minimize the effect of this gene, individual plants of the F2 population were selected for self-pollination based on presence or absence of Stb14 using flanking microsatellite markers. The Stb14(+) F2:3 families were screened with M. graminicola isolate MG96-36. Bulked segregant analysis identified a possible linkage to the gene of interest on chromosome 3AS. Polymorphic microsatellite markers on 3AS were used to construct a linkage group. The markers barc321 and barc12 were found to flank the resistance gene at genetic distances of 1.9 and 2.5 cM, respectively. This position on 3AS has not been previously linked to Stb resistance and this gene will be designated StbSm3. The third population was developed to fine map the isolate-specific resistance gene Stb14 located on chromosome 3B of Salamouni. A large population of 84 fixed recombinant F4 families was developed using the co-dominant microsatellite markers flanking Stb14. Attempts to identify clearly polymorphic molecular markers within the interval containing Stb14 were unsuccessful.

No description available.

No description available.