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Aegilops columnaris is a tetraploid species originated from Ae. umbellulata (2n=2x=14, UU) and a yet unknown diploid grass species. Although Ae. columnaris possesses some agronomically valuable traits, such as heat and drought tolerance and resistance to pests, it has never been used in wheat breeding because of difficulties in producing hybrids and a lack of information on the relationships between Ae. columnaris and common wheat chromosomes. In this paper, we report the development of 57 wheat – Ae. columnaris introgressive lines covering 8 of the14 chromosomes of Aegilops. Based on substitution spectra of hybrids and the results of FISH analysis of the parental Ae. columnaris line with seven DNA probes, we have developed the genetic nomenclature of the Uc and Xc chromosomes. Genetic groups and genome affinities were established for 11 of 14 chromosomes; the classification of the remaining three chromosomes remains unsolved. Each Ae. columnaris chromosome was characterized on the basis of C-banding pattern and the distribution of seven DNA sequences. Introgression processes were shown to depend on the parental wheat genotype and the level of divergence of homoeologous chromosomes. We found that lines carrying chromosome 5Xc are resistant to leaf rust; therefore, this chromosome could possess novel resistance genes that have never been utilized in wheat breeding.

One thousand and ninety-seven Aegilops accessions were evaluated for their reaction to a PAV serotype of barley yellow dwarf luteovirus (BYDV). The accessions tested belong to the species bicornis, biuncialis, caudata, crassa, columnaris, comosa, cylindrica, kotschyi, longissima, mutica, neglecta (= triaristata 4 ×), ovata, peregrina, searsii, sharonensis, speltoides, tauschii (= squarrosa), triuncialis, umbellulata, uniaristata, vavilovii and ventricosa. The first evaluation of virus levels in the different accessions was conducted at International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria, using double antibody sandwich ELISA (DAS-ELISA). Accession reaction ranged from highly resistant to highly susceptible. Thirty-eight Aegilops accessions resistant at ICARDA, were evaluated at Sainte-Foy, Quebec, Canada, by tissue-blot immunoassay. Diversity of response to BYDV infection was again observed in this elite group. Seven accessions belonging to the species biuncialis, caudata, neglecta and triuncialis were highly BYDV resistant at both locations; five of these originated from Bulgaria. Key words: Introgression, interspecific, Triticum aestivum, BYDV, ELISA, immunoassay, tissue blot

Antibody synthesis, in response to vaccination with a 0.1-ml (1.8 × 108 cells/ml) intraperitoneally injected, heat-killed strain of Flexibacter columnaris, was employed to investigate the effect of tritium irradiation (0, 0.04, 0.4, 4.0, 40 rads total dose for 20 days during embryogenesis) on development of the primary immune response in 5-mo rainbow trout, Salmo gairdneri, reared under essentially pathogen-free conditions. Specific agglutinins to F. columnaris, determined 1-wk pre vaccination, and 3, 5, 7, 9, and 11 wk postvaccination increased rapidly in both control and irradiated fish following vaccination. Agglutinin levels in irradiated fish were suppressed to 50% of control levels at 40 rads during the 9th wk, and 50% of control levels at 4.0 rads during the 11th wk. Electrophoretic separation of serum proteins of both control and irradiated–vaccinated fish demonstrated four major protein fractions. Densitometry analyses demonstrated that fraction IV increased significantly in percent of total protein following antigenic stimulation, suggesting that fraction IV represents the specific humoral antibody to F. columnaris. The relative percent of total protein contained in fraction IV was significantly reduced in irradiated–vaccinated fish. Key words: antibody synthesis, agglutination assay, vaccination, Flexibacter columnaris, tritium, Salmo gairdneri, electrophoresis, serum protein, densitometry, primary immune response

The effect of water temperature upon mortality from experimental infection by Flexibacter columnaris and on mean time to death was investigated in juvenile steelhead trout (Salmo gairdneri), coho salmon (Oncorhynchus kisutch), and spring chinook salmon (Oncorhynchus tshawytscha). Eight temperatures increasing from 3.9 to 23.3 C (39 to 74 F) by increments of 2.8 C (5 F) were studied. Fish were infected by the direct contact method whereby a suspension of the pathogen was added to the water. It was found that at temperatures of 9.4 C (49 F) and below, no deaths due to the experimental infection with F. columnaris occurred. At 12.2 C (54 F) mortality varied from 4 to 20% among the three species, and increased progressively with increasing temperature to 100% in steelhead trout and coho salmon at 20.5 C (69 F), and 70% in chinook salmon at that temperature. With all three salmonid species, an inverse linear relationship was found between water temperature and the log10 of the mean number of days from exposure to death. This means that as the temperature increased above 12.2 C (54 F), the disease process was progressively accelerated, resulting in a minimum time to death at 20.5 or 23.3 C (69 or 74 F) and a maximum at 12.2 C (54 F). The results indicate that under the conditions of these experiments, columnaris disease in salmonids was completely suppressed by water temperatures of 9.4 C (49 F) or below.

Pragmopycnis pithya gen. et sp. nov. is introduced for the conidial state of Pragmopora pithya (Fr.) Groves and is characterized by simple, solitary, brown pycnidia, integrated polyphialides, and hyaline, allantoid, aseptate conidia. A comparison is made with Sirodothis Clements, which provides an earlier name for Pleurophomella Höhnel, a name currently adopted for the conidial states of Tympanis Tode ex Fr. Sirodothis populnea (Thüm.) comb, nov., S. saligna (Höhn.) comb, nov., S. inversa (Fr.) comb, nov., and S. columnaris (Wallr.) comb. nov. are proposed for the named conidial states of four Tympanis species.

A study of the species of Entyloma on North American composites suggests that almost every form can be assigned to one of two phyletic groups. E. polysporum contains most of the forms with densely crowded, rather large teliospores and no conidia. E. Davisii on Rudbeckia hirta and, probably, a fungus on Lepachys columnaris are segregated from it. E. Compositarum contains most of the forms with smaller, uncrowded spores and abundant conidia. E. arnicale and possibly one or two other forms may be regarded as segregates from this species.Emended descriptions of E. polysporum and E. Compositarum are given to clarify the differences between these two species. Corrections are also made in the identification of some exsiccati specimens.Comparisons are made with European forms to the extent that material has been available, but far more study of European specimens is needed to allow assessment of some species.Species concepts for these fungi are discussed, and criteria are suggested for adequate morphological studies.

Survival curves for spores of Aspergillus flavus Link var. columnaris Raper and Fennell were obtained after their irradiation with gamma rays in the presence of Na+, K+, and Ca2+ halogens. Halogens of Na+ and K+ sensitized the spores to the radiation and enhanced sensitization occurred as the dose of radiation was increased. Halogens of Ca2+ protected the spores against a radiation dose of 25 krad but at higher doses although CaCl2 was protective, CaBr2 and CaI2 were radiosensitizers, with CaI2 the most efficient radiosensitizer.

Columbia River fish ladders were surveyed as a possible ecological niche for Chondrococcus columnaris, the causative agent for columnaris disease of fishes. Water samples from Bonneville, McNary, Priest Rapids, and Rocky Reach fish ladders during periods of warm-water temperature and high population density of fishes showed C. columnaris levels of from 0.06 to 4.1 organisms/ml. Samples taken upstream or downstream from the ladders were consistently negative. Average agglutinating titers and incidence of C. columnaris infection in largescale suckers were higher at the Bonneville ladder than at a site several miles downstream Coho salmon from an upper-river fish ladder (Rocky Reach) showed a higher incidence of infection and greater antibody production than at the downriver Bonneville ladder. It is concluded that fish-ladder facilities on the Columbia River are important sites for repetitive exposure of anadromous salmonids to C. columnaris.

Active immunity to Chondrococcus columnaris disease was established in coho salmon (Oncorhynchus kisutch) approximately 3 months old by oral vaccination with heat-killed cells. Average agglutinating titers were 1:17 for control survivors and 1:168 for the orally vaccinated salmon. When rainbow trout (Salmo gairdneri) approximately 3 months old were exposed in a trough to C. columnaris present as a natural contaminant in Columbia River water, 52% of the fish died during the first 6 weeks of the test. Fish that survived the exposure were generally resistant to subsequent challenge. Many age 1 + rainbow trout that survived the C. columnaris infection as juveniles, when sampled after several months of reexposure to the disease, were immune carriers of the pathogen and developed agglutinating antibody titers ranging from 1:80 to 1:640. Titers up to 1:5120 were developed in disease-free yearling rainbow trout by parenteral vaccination.

River fish populations infected with Chondrococcus columnaris disease were surveyed by measurements of C. columnaris agglutinating antibodies in blood sera of fishes and by isolation of the pathogen using microbiological plating methods. Agglutinins were demonstrated in all 13 fish species collected except whitefish (Prosopium williamsoni). Blood serum from samples of fishes at four Columbia River sites during 1965 and three Columbia River sites and one Snake River site during 1969–70 demonstrated single annual cycles of C. columnaris antibody production. During the two annual sampling periods, the magnitude of antibody titers and frequency of fish with agglutinins increased in warm water and declined in cool water. The rise in titers occurred after a winter low, and usually followed the period when the first C. columnaris organisms were isolated from native fish. Agglutinating titers up to 1:5000 were found but most peak titers were between 1:320 and 1:640.