Influence of phosphomide, a chemical mutagen, on agrobiological signs of soft spring wheat Triticum aestivum L

The method of chemical mutagenesis allows in a relatively short time to obtain a material with new features and properties, including completely new mutations. The effectiveness of the application of the method for the creation of selection valuable forms of plants in various soil and climatic conditions is shown in the works of a number of authors. The purpose of this work was to study the effect of the mutagen namely phosphomid in different concentrations on the agrobiological characters at the hybrid form and the initial cultivars of spring soft wheat ( Triticum aestivun L.). Two domestic cultivars (Scant 1, Scant 3, var. lutescens ) and three foreign cultivars (Cara, var. erythrospermum ; Hybrid, var. ferrugineum ; Lutescens 70, var. lutescens ) were the source material. A preliminary study of the varieties was carried out in 2006-2008. In 2009, hybrid combinations involving these varieties were obtained using incomplete diallel crosses and forced pollination. The efficacy of phosphomide, a chemical mutagen, at concentrations of 0.002 and 0.01 % was studied in two varieties (Cara and Scant 3) and F4 hybrid (Cara ½ Scant 3). For the treatment, the seeds were soaked in phosphomide solutions for 3 hours, and the control seeds were soaked in distilled water. Germination energy and morphometric parameters of the seedlings were evaluated in laboratory tests to calculate the growth inhibition indices. In the spring 2014, 25 mutagen-treated seeds were sown in the field (Biostation of Tyumen State University, Tyumen Province) in 4-fold replication separately for each variant of treatment to obtain M1 generation. From individual M1 plants were separately derived M2 generation. Resistance of the specimens toward leaf fungus diseases (powdery mildew, leaf rust and spotting) was assessed under natural infection development (Biostation of Tyumen State University, Tyumen Province) during the entire vegetation period, from appearance of the symptoms till the leaves dried up, using laboratory tests for specific pathogen identification. The results obtained suggest that the use of phosphomide promotes diversity of the breeding material. In the first generation (M1), there was an inhibitory effect of phosphomide on field wheat germination and the morphometric parameters of seedlings (the length of roots and shoots) which depended on the mutagen concentration. The seedlings showed the least tolerance to phosphomide as to the number of germinal roots. The effect of stimulation compared to the control occurred in the hybrid combination Cara ½ Scant 3 as to seed germination energy indices (by 5.9 %) in the laboratory tests and plant viability in the field during the growing season (by 14.0-80.0 %). The mutagen increased significantly the grain weight per 1 m2 in the hybrid (by 16.0 %) while the grain yield in the varieties Cara and Scant 3 decreased by 67.0 and 57.0 %, respectively. In high concentration (0.01 %) the mutagen reduced resistance to powdery mildew and brown rust in the varieties whereas in the hybrid at the same concentration the susceptibility to powdery mildew decreased, and to brown rust - increased. The phenotypic changes in M2 were assessed according to the morphology of the ear, stem, leaves (color, pubescence, shape, size) and biological properties (late ripening, early ripening, winter type plants). In total, there were 12 types described. Plants with a large ear, strong stems, stunted and dwarfs were more common in the hybrid (13.6-20.0 % of the total number of modified forms). The varieties often produced early ripening forms (16.4-24.2 %). The proportion of families with altered plants in the varieties was 5.3 % less than in the hybrid. The highest rate of modifications in the varieties and the hybrid was influenced by 0.01 % concentration. Thus, it is shown that phosphomide at concentrations of 0.002 and 0.01 % is effective to improve agronomically important characteristics in the varieties and intraspecies hybrid of soft spring wheat.