Wheat dwarf virus and its impact on the 2020 harvest in some regions of Ukraine

Goal. Identify the virus that causes symptoms of dwarfism and non-earing of winter wheat (reduced or no ear formation), and investigate its effect on plant yields. Methods. Visual diagnostics, enzyme-linked immunosorbent assay in double sandwich modification (DAS-ELISA), polymerase chain reaction, biometric, determination of yield and its structure, statistical data processing. Results. A study of winter wheat varieties from Vinnytsia, Khmelnytsky, Kyiv, Chernihiv and Cherkasy regions with symptoms of dwarfism, yellowing of leaves and non-earing. ELISA and PCR have shown that the disease is caused by Wheat dwarf virus. The absence of Wheat streak mosaic virus, Barley yellow dwarf virus, Brome mosaic virus and Wheat spindle mosaic virus (Wheat streak mosaic virus) was shown in the studied samples. It was found that the dwarf wheat virus significantly reduces the number of grains in the ear (3.3 times), the weight of grains from the ear (3.4 times) and the weight of 1000 grains (1.9—3.3 times) depending on the degree of damage plants (from moderate to severely affected). Conclusions. The circulation of dwarf wheat virus in agrocenoses of five regions of Ukraine and a significant negative impact of the disease on the yield of winter wheat plants have been established. The obtained results indicate the need for constant monitoring and testing of plants for the presence of wheat dwarf virus in Ukraine.

Ancient Wheat Species (Triticum sphaerococcum Perc. and T. persicum Vav.) in Organic Farming: Influence of Sowing Density on Agronomic Traits, Pests and Diseases Occurrence, and Weed Infestation

Crop management should be determined to reintroduce ancient wheat. This study aimed to determine: i. the response of the yield of ancient wheat on sowing density; ii. the impact of sowing density on plant health, weed infestation and pest occurrence. Field experiments were carried out in Poland, on three organic farms. The factors were: (1) wheat species: Persian wheat (Triticum persicum Vav.) and Indian dwarf wheat (T. sphaerococcum Perc.), (2) sowing density (400, 500, and 600 grains m−2). Increasing the sowing density of T. sphaerococcum from 400 to 600 grains m−2 increases the grain yield and reduces the pest pressure (Oulema spp. and Aphididae). Sowing densities did not affect the severity of powdery mildew at stem elongation as well as root rot and eyespot at the development of fruit. At the highest sowing density, the leaf area with tan spot symptoms was the highest. The eyespot symptoms occurred more frequently and the damaged plant surface caused by Oulema spp. was larger on T. sphaerococcum. Persian wheat turned out to be more susceptible to weed infestation. Indian dwarf wheat and Persian wheat are useful for organic farming, and the sowing density should be 500 or 600 grains m−2 and 400 grains m−2, respectively.

Recovery of Wheat Heritage for Traditional Food: Genetic Variation for High Molecular Weight Glutenin Subunits in Neglected/Underutilized Wheat

Club wheat (Triticum aestivum L. ssp. compactum (Host) Mackey), macha wheat (T. aestivum L. ssp. macha (Dekapr. & A.M. Menabde) Mackey) and Indian dwarf wheat (T. aestivum L. ssp. sphaerococcum (Percival) Mackey) are three neglected or underutilized subspecies of hexaploid wheat. These materials were and are used to elaborate modern and traditional products, and they could be useful in the revival of traditional foods. Gluten proteins are the main grain components defining end-use quality. The high molecular weight glutenin subunit compositions of 55 accessions of club wheat, 29 accessions of macha wheat, and 26 accessions of Indian dwarf wheat were analyzed using SDS-PAGE. Three alleles for the Glu-A1 locus, 15 for Glu-B1 (four not previously described), and four for Glu-D1 were detected. Their polymorphisms could be a source of genes for quality improvement in common wheat, which would permit both their recovery as new crops and development of modern cultivars with similar quality characteristics but better agronomic traits.