Colonization of the winter wheat (Triticum aestivum L.) rhizoplane by root-inhibiting nonfluorescent pseudomonads was investigated in laboratory and greenhouse studies with genetically marked (rifampicin resistant) isolates. Colonization was similar at root zone temperatures of 5, 10, and 15°C but was dependent on soil type, with higher populations occurring in the soil with lower organic matter and microbial biomass. Rhizoplane populations of test strains were over tenfold higher on roots in pasteurized soil than in non-pasteurized soil or vermiculite. Deleterious effects on growth of winter wheat were related to the extent of rhizoplane colonization by the bacteria; approximately 10⁶ colony forming units (cfu) mg⁻¹ root were required for significant inhibition of root growth. The shoots and roots of winter wheat were significantly shorter on plants inoculated with the inhibitory bacteria in pasteurized or methyl bromide fumigated soil as well as in nonpasteurized Ritzville soil (Calciorthidic Haploxerolls). The difference in early stages of plant growth, especially shoots, between bacterized (seed treated with antibiotic-resistant inhibitory bacteria) and nonbacterized winter wheat increased with time. The antibiotic-resistant bacteria maintained a high population on the roots during this period. The bacteria were observed to extensively colonize winter wheat roots (rhizobacteria) and are considered a potential constraint on winter wheat yield in the Pacific Northwest.

shIn soil environments (brown soil formed on loess or loess-like sediments) with definite specialized crop rotations (1 - maize, sugar beet, barley, clover, winter wheat, 2 - winter wheat, winter wheat, maize, winter wheat) the occurrence of toxin forming fungi from genera Aspergillus, Fusarium, Penicillium and Trichothecium has been ascertained. Actinomycetes of genus Streptomyces and fungi of genus Penicillium were isolated from the soils. The microorganisms showed specific capacities pertaining to the adsorption of aflatoxins: B1, B2, G1 and G2. The efficiency of the process of aflatoxin adsorption occurs within 38.6% and 97.4% and depends on the properties of strains, number of cells and growth dura

Where furrow irrigation is practiced, the residue from the previous crop must be removed from the soil surface to prevent furrow blockage, resulting in disuniform irrigation. High energy and labor costs have caused some producers to consider burning the residue rather than incorporating it. Thus, a 14-year study was conducted on a clay loam soil (fine, mixed, mesic Torrertic Paleustall) in north Texas to test the long-term effects of straw management on land cropped continuously to irrigated winter wheat (Triticum aestivum L). The study included three management treatments: i) residue incorporated into the soil, ii) residue mechanically removed, and iii) residue burned. All other management practices were identical. All treatments caused the soil organic matter in the top IS cm to increase from 1.29 2 years after being broken from native sod to 2.11% during the study. Incorporation of wheat residue did not increase soil organic matter to a greater extent than burning or removing wheat residue. Soil water infiltration was not affected by burning. While grain yield showed considerable variation among years, there were no differences in yield attributable to burning or incorporation of wheat residue.

A newly created and acknowledged winter wheat variety in Yugoslavia is "Sivka" created in the Plant Improvement and Production Institute in Zagreb. "Sivka" is a high-yielding winter wheat variety, having red-grey colour of maturing ears, with very short awn on terminal spikelets, medium-high stalk, satisfactory lodging resistance, very good cold, mildew and black wheat rust resistance, satisfactory leaf rust resistance, good adaptability to later autumn sowing terms and later harvest and gives a good quality grain with improved properties.