Anther culture of Hordeum vulgare L.: a genetic study of microspore callus production and differentiation

The inheritance of the ability of barley anthers to produce microspore-derived callus in vitro was investigated. The genotypes selected were the two spring cultivars 'Dissa' (D) and 'Sabarlis' (S), the two F1 hybrids (DxS, SxD), the two backcross generations [Dx(DxS), Sx(DxS)], and an F2 generation derived from DxS. From a number of individuals of each generation, the first five spikes were harvested sequentially and after pre-treatment the anthers were removed and placed in culture. Cultures were scored for microspore callus production and plantlet differentiation. Although 'Dissa' gave a significantly higher level of callus production than 'Sabarlis', the overall frequencies of green and albino plant production were higher from 'Sabarlis'. There was no significant difference between reciprocal F1 hybrids. Analysis of variance revealed significant differences in response between the spikes sampled from the plants. This was the major source of variation in the experiment. Spike to spike variation also appeared to be a heritable character.

Genetical analysis of microspore derived plants of barley (Hordeum vulgare)

From an F1 hybrid between the two barley (Hordeum vulgare L.) cultivars 'Golden Promise' and 'Mazurka' a series of doubled haploid (DH) lines were generated both from microspores by anther culture and from immature zygotic embryos after hybridization withH. bulbosum. The DH lines from both sources were used to monitor the segregation of the five major genes, rachilla hair length, DDT susceptibility, height, C hordein polymorphism and mildew resistance. Whereas the microspore-derived samples showed significant departures from the expected 1∶1 ratio for three of the five genes, theH. bulbosum lines showed deviation for only one gene. Analysis of linkage data also showed differences between the two series of DH lines. Cytogenetic analysis revealed a mean chiasma frequency in theH. bulbosum lines which was very similar to the F1 hybrid. In contrast, four of the ten microspore derived lines examined showed a reduced chiasma frequency. One showed evidence of translocation heterozygosity.

Field performance of lines derived from haploid and diploid tissues of Hordeum vulgare

Plant tissue culture technology is of increasing interest to plant breeders. As part of a continuing investigation into breeding methods with spring barley two studies were conducted to assess the field performance of the progenies of material regenerated in tissue culture. The first study involved two spring barley cultivars, 'Golden Promise' and 'Mazurka' and compared lines produced from immature embryo (IE) derived callus with those from embryos developed by the Hordeum bulbosum (Hb) technique of chromosome elimination. In general the mean values for the seven characters scored were lower for the IE than the Hb material. In the second study F1 hybrid material ('Golden Promise'x'Mazurka') was used and doubled haploid lines produced by the H. bulbosum and microspore culture (M) techniques were compared with single seed descent (SSD) material. Analysis of these F∝ samples indicated that the mean values for the M lines were significantly lower than those of the Hb and SSD lines. Furthermore, data from the M lines showed significant evidence of variation created during the culture phase. The implications of these findings for barley breeding are discussed.

Investigations into the linkage of genes controlling individual quantitative characters in barley

Technical innovations in barley breeding have resulted in the ability to reduce generation times. Single seed descent and doubled haploidy have become practical propositions in barley improvement. These Fx samples are also powerful tools for genetical analyses and have been used in this paper together with conventional generations to investigate the linkage of genes controlling quantitative characters. Such investigations are of relevance to barley breeders since the detection of significant levels of repulsion linkages would indicate that the single seed descent (SSD) technique would be preferable to doubled-haploid (DH) methods. The present study indicated that estimates of D (the additive genetic variance) from DH and SSD sampled did not differ significantly. Thus linkage disequilibrium is not an important component of the genetic architecture of the five crosses investigated. Hence F1-derived doubled haploids or SSD will be equally effective in producing desirable recombinant inbred lines.Key words: Hordeum, doubled haploids, linkage disequilibrium.

Genetical investigations into β-glucan content in barley

Random inbred lines produced by doubled haploidy (DH) and single seed descent (SSD) have been used to investigate the genetics of β-glucan (gum) content in barley (Hordeum vulgare). Genetical analyses indicated that gum content is controlled by a simple additive genetic system. Significant negative genetic correlations were observed between β-glucan content, thousand grain weight and height in the DH samples. These correlations were much reduced in the SSD samples and would suggest linkage of the genes controlling these characters. The presence of repulsion linkages could be exploited in a barley breeding programme by producing F1 derived DH to generate recombinants with high thousand grain weight and low β-glucan content. Genetical parameters estimated from DH and F3 samples have successfully been used to predict the number of inbred lines transgressing the parental range for β-glucan content and bivariate combinations involving β-glucan.

Competitive effects in monocultures and mixtures of spring barley (Hordeum vulgare)

The presence of significant levels of intergenotypic competition amongst barley (Hordeum vulgare) genotypes has profound consequences for barley breeding programmes. Breeding programmes based on the pedigree system attempt to identify genotypes in genetically heterogeneous populations but the elite genotypes are grown in monoculture. Thus, to attain varietal status genotypes produced by this breeding strategy must perform well in mixtures as well as in pure stands. The effectiveness of early generation selection may be hampered by intergenotypic competition. To examine this problem in spring barley, a modified substitution experiment (Mather and Caligari 1981, 1983) was used and included genotypes sampled from a random set of inbred lines generated without conscious selection. This approach to the investigation of competitive effects in barley indicated the presence of significant levels of intergenotypic competition for a range of agronomic characters. The analyses allowed a distinction to be made between aggression (a) and response (r) with the component r displaying greater variation than a. The lack of correlation in the distribution of a and r suggested that they were under separate genetic control and hence adjustable by selection. The implications of these results for barley improvement, the use of varietal mixtures and mixed cropping are discussed.

Auricular perichondritis secondary to acupuncture

Auricular perichondritis developed in a patient following acupuncture to the pinna. Poor response to high-dose antibiotics necessitated open drainage. The underlying cartilage was uninvolved, and minimal deformity ensued. Acupuncture must be considered a form of penetrating trauma that may induce a perichondritis or chondritis in the auricle.

The use of pollen irradiation in barley breeding

Second generation progenies (M2) derived from crosses using barley pollen irradiated at 500, 1,000 1,500 and 2,000 rads increasingly resembled the maternal parent. 'Golden Promise', but contained some characteristics derived from the paternal parent, 'Magnum'.

Plasma kinetics of digoxin in the cat

The biological half-life of digoxin was 33.3 +/- 9.5 hours in 6 cats after a single IV injection. Longer half-lives were obtained after chronic oral administration, indicating that digoxin elimination is capacity-limited in the cat. The mean percentage of urinary excretion of digoxin after a single IV dose was 45% +/- 9.7% over a 10-day period. Toxic plasma concentrations ranged from 2.4 to 2.9 ng/ml, and 5 of 6 cats had clinical signs of toxicosis at concentrations greater than 2.6 ng/ml. Prolongation of the PQ interval was seen on the ECG at nontoxic plasma concentrations in 4 of 6 cats. The most striking ECG evidence of digoxin toxicosis was ST-segment elevation seen in 3 of the 6 cats.

Cervical synovial sarcoma at the bifurcation of the carotid artery

Cervical synovial sarcoma has been reported in only 15 cases; in none of these was there any association with a vascular structure. A patient with cervical synovial sarcoma encompassing the bifurcation of the left carotid artery underwent a left radical neck dissection, including excision of the left external carotid artery and the hypoglossal nerve. The tumor was dissected away from the common carotid and internal carotid arteries. Although the fibrous pseudocapsule of the tumor had not involved the fibrous adventitia of the carotid arteries. Radiation therapy with 6000 rads tumor dose was administered to a wide local field. There is no evidence of recurrence 1 year postoperatively. Histologic and ultrastructural findings were similar to those reported previously in a case of synovial sarcoma of an extremity.

Supercooling and the low-temperature survival of the green spruce aphid Elatobium abietinum

Laboratory investigations into the low-temperature tolerance of the green spruce aphid, Elatobium abietinum, revealed that the insect was killed by freezing. Aphids and host Sitka spruce needles showed similar seasonal changes in supercooling ability. A noticeable increase in this ability occurred between June and October. Aphids were more susceptible to low temperatures when attached to the plant. It is suggested that mortality resulted from ice which formed in the sap of the host needles and spread into the feeding aphids via their mouthparts. Neither the chlorotic banding of needles, caused by aphid feeding, nor needle length affected needle supercooling. Increased duration of exposure increased the probability of freezing of supercooled needles at low temperatures. A small percentage of first-instar nymphs supercooled to much lower temperatures than the remainder of the population. These were newly born nymphs whose high supercooling ability markedly decreased when they began to feed.

Chemistry of the aminochromes. Part XIII. Some further observations on the reactions of the aminochromes with thioglycollic acid

Thioglycollic acid reacts with adrenochrome in aqueous solution to give 5,6-dihydroxy-1-methylindole and 4-S-carboxymethylthio-5,6-dihydroxy-1-methylindole, together with smaller amounts of the lactone obtained by intramolecular cyclization of the latter compound. When the reaction is carried out in the absence of water the relative amount of 5,6-dihydroxy-1-methylindole formed is markedly reduced. At lower temperatures 4-S-carboxymethylthio-5,6-dihydroxy-1-methylindole is the main product obtained, whilst at higher temperatures the corresponding lactone predominates.The major products obtained by the action of thioglycollic acid on 4- and 7-methyladrenochrome in aqueous solution were 5,6-dihydroxy-1,4-dimethylindole and 4-S-carboxymethylthio-5,6-dihydroxy-1,7-dimethylindole respectively.

Chemistry of the aminochromes. Part X. Some further observations on the reactions of aminochromes with thiols

The reactions between aminochromes and thiols have been reinvestigated. In general aminochromes react with thiols to give mixtures of products including: 5,6-dihydroxyindoles; thio-substituted 5,6-dihydroxyindoles (the mercapto residue is now considered to be in the 4-position of the indole nucleus and not the 7-position as previously reported); and relatively unstable addition products formed between the aminochrome and the thiol. The mechanisms by which these compounds are formed are discussed. The characterization of three thio-substituted 5,6-dihydroxyindoles by nuclear magnetic resonance spectroscopy is described. The nuclear magnetic resonance spectra of a number of 5,6-diacetoxyindole derivatives are reported.