Characterization of resistance to the wheat stem sawfly in spring wheat landrace accessions from targeted geographic regions of the world

Plant landraces have long been recognized as potential gene pools for biotic and abiotic stress-related genes. This research used spring wheat landrace accessions to identify new sources of resistance to the wheat stem sawfly (WSS) (Cephus cinctus Norton), an important insect pest of wheat in the northern Great Plains of North America. Screening efforts targeted 1409 accessions from six geographical areas of the world where other species of grain sawflies are endemic or where a high frequency of accessions possesses the resistance characteristic of solid stems. Resistance was observed in approximately 14% of accessions. Half of the lines displayed both antixenosis and antibiosis types of resistance. Among the resistant accessions, 41% had solid or semi-solid stems. Molecular genetic screening for haplotypes at the solid stem QTL, Qss.msub.3BL, showed that 15% of lines shared the haplotype derived from ‘S-615’, the original donor of the solid stem trait to North American germplasm. Other haplotypes associated with solid stems were also observed. Haplotype diversity was greater in the center of origin of wheat. Evaluation of a representative set of resistant landrace accessions in replicated field trials at four locations over a three year period identified accessions with potential genes for reduced WSS infestation, increased WSS mortality, and increased indirect defense via parasitoids. Exploitation of distinct types of plant defense will expand the genetic diversity for WSS resistance currently present in elite breeding lines.     

Synthesis and fungicidal activity of phenanthridinotriazines: A structure–activity relationship study

A series of analogous tetracyclic 1, 12b-dihydro-4H-1,2,4-triazino[4,3-f] phenanthridines and 4H,12bH-1,2,5-oxadiazino[5,6-f]phenanthridines was prepared and tested for control of Erysiphe graminis f. sp. tritici (the causal agent of powdery mildew in wheat). Several analogs showed exceptional activity at doses as low as 6.25 mg litre^?1 with substituted analogs VII, X , and XIV being the most potent. Singly substituted tetrahydrotriazinyl or oxadiazenyl rings with lipophilic aromatic components appeared to be the key requirements for optimal powdery mildew control. Substitution of the heterocyclic ring with multiple groups attenuated activity.     

Lymphoproliferation in captive wild ruminants affected with malignant catarrhal fever: 25 cases (1977-1985)

The severity of lymphoproliferative disease associated with malignant catarrhal fever was extremely variable among 25 animals at the San Diego Wild Animal Park. Severe lymphoproliferative disease was seen in 3 of 10 Formosan Sika deer (Cervus nippon taiouanus), 3 of 6 Indian Axis deer (Cervus a axis), 3 of 6 Barasingha deer (Cervus d duvauceli), and 1 of 3 Nilgai (Boselaphus tragocamelus). Two Sika deer and 2 Barasingha deer had lesions morphologically indistinguishable from lymphosarcoma. Our findings were consistent with the hypothesis that alcelaphine herpesvirus-1 has oncogenic potential.     

A kinetic study of the acetylation of cellulose, hemicellulose and lignin components in wood

The rates of acetylation of Deal, Larch, Southern Yellow Pine and Sitka Spruce using acetic anhydride in xylene have been measured and compared with the composition of the woods. Although these woods have similar macroscopic characteristics, the correlation between rate of acetylation and composition remains unclear, although the holocellulose may play a role in converting the hydrophilic hydroxyl groups to hydrophobic acetyl groups. The rate of acetylation of Larch at 373 K was insignificant but the other wood samples showed significant acetylation at this temperature. The activation energies for the acetylation process suggest that several routes may be involved.     

Alpha-amylase/subtilisin Inhibitor Levels in Australian Barleys

An enzyme-linked immunosorbent assay (ELISA) was used to determine the bifunctional alpha-amylase/subtilisin inhibitor (BASI) content of barley grain from 11 cultivars grown in six diverse locations in Australia. The inhibitor ranged from 119 to 254 μg/g in 57 barley samples. Genotype had a significant (P<0·05) effect on BASI content but there was no effect due to environment. Total protein varied independently of BASI and was influenced by environment and genotype. BASI content was higher (P<0·05) in malting barley than in feed barley and was correlated positively (r=0·29;P<0·05) with alpha-amylase activity in corresponding malts. The ELISA used monoclonal and polyclonal antibodies raised against purified BASI. In immunoblot analysis the monoclonal antibody showed high specificity for the inhibitor in barley and also detected the inhibitor in wheat. Low levels of inhibitor (mean 3·2 μg/g) were found in 12 Australian wheat cultivars using the ELISA developed for barley. The assay had a linear working range of 5–50 ng/mL with a detection limit of 2 ng/mL. Reproducibility between assays was good (CV=4·9%) but mean recoveries were high, ranging from 116–129% when purified inhibitor was added to barley extracts. The ELISA may have useful applications in brewing research and barley breeding programmes.