NEW SOURCE MATERIAL FOR WINTER WHEAT BREEDING FOR RESISTANCE TO DISEASES

The results of immunological studies of winter wheat collection samples and hybrid fami-lies F 6 -F 8 on infectious and provocative backgrounds of the most common diseases were analyzed.

experimental plots and every 20 numbers. Counts of affected plants and determination of the resistance of samples under investigation were carried out according to the scales and procedures given in the methodological recommendations [7,8]. The plant resistance to pathogens was assessed in dynamics; the assessment in the period of maximum development of diseases was considered the basic one.
Results. Phytosanitary status of all crops and winter wheat, in particular, is affected by all environmental factors and their fluctuations. Air and soil temperature and humidity, which influence spore germination, disease progression, changes in dominant hazardous species in pathogen populations, formation of new races, etc., are the most important for the development of fungal diseases in plants.
Recently sharp fluctuations of meteorological factors there have occurred: winters with subzero temperatures that are critical for wheat overwintering with almost frost-free ones alternate; years with dry conditions during the summer vegetation period prevail, and there are years with great amounts of precipitations, mainly shower rains. Almost every second year is characterized by moisture deficiency during the optimal planting terms, cases of late frosts are also noted, etc.
Weather conditions inhibit or provoke the development of various diseases, so a reliable estimation of collection and breeding material should be carried out on artificially formed infectious and provocative backgrounds. The study years (2011-2013) differed both in winter and in spring-summer weather conditions of winter wheat vegetation period.
The overwintering period during January -March in 2011 was rated as satisfactory, while the weather conditions in spring and summer months were favorable for the development of winter wheat leaf diseases and head smut. Deviations both in temperature and in the amount of precipitations upwards as compared with the long-term data were noted (Fig. 1, 2).
The amounts of precipitation in June and in July were remarkably different from the many year values (63.3 mm) -194.6 mm and 91 mm, respectively, at a rather high temperature -20.8-23.0 °C on average per month, which was the impetus for the development of fungal diseases in plants.
The winter wheat overwintering in 2012 was complicated by the autumn drought, and then by the abnormally warm winter. Because of the sharp warming and drought in April and, as a consequence, a rapid recovery of winter crop vegetation, no snow mold on crops was observed. The abundant May morning dew in 2012 contributed to infecting leaves by Septoria spot agents, but the pathological process was slowed down because of the subsequent drought in May, June and July (27.2, 48.3 and 20.3 mm of rainfall, respectively), high temperatures and low air humidity. The development of the powdery mildew pathogen, which is adapted to wider temperature and humidity ranges, continued in winter wheat plants.

Fig. 2. The rainfall amounts in the spring and summer vegetation periods of winter crops
The winter in 2013 was rather mild; the minimum soil temperature at the depth of winter wheat tillering node did not drop below -6 °C. The overwintering of winter crops took place inder satisfactory conditions . In the 1 st decade of April winter wheat vegetation resumed. Huge temperature swings, storms, frosts were observed. The first half of May was also very dry. On the last days of the 2 nd decade of May it rained, mainly shower rains were noted, on the whole 44.8 mm precipitated over this month. The improvement in soil moisturing and air humidity increasing contributed to the penetration and spore germination of fungal diseasestan spot, leaf septoriosis, powdery mildew. In June the warm weather prevailed, the mean monthly temperature reached 22.9 °C, the maximum temperature was 33.1 °C. The precipitations were irregular, mostly shower rains, (the precipitation amount per month was 52.3 mm), the mean monthly relative humidity ranged from 40 % to 88 %, while there were 11 days with the air humidity exceeding 60 %, the soil moisturing was satisfactory. In July the weather was unstable with heavy rains and temperature swings, especially at night and by day. The precipitation amount for July was 66.6 mm; the air humidity ranged from 46 % to 94 %, and in the 3 rd decade of July on all the days the humidity was above 60 %. No brown leaf rust was observed in plants, which is attributed to winter wheat ripening earlier than usual. Among the fungal diseases leaf ones prevailedtan spot and septoriosis.
During the study years the levels of infectious and provocative backgrounds were sufficient to differentiate samples by resistance to the powdery mildew, septoriosis and head smut pathogens. The incidence in the susceptible varieties-standards over the study years ranged from 55 to 65 % in the variety Borvyy (the reference variety of susceptibility to septoriosis), up to 40 % in the variety Agassis (the reference variety of susceptibility to powdery mildew), and from 70 to 90% in Donetskaya 48 (the reference variety of susceptibility ti head smut). The natural background of snow mold amounted to 90 % in 2011 and 2013. During the study years rust diseases ~ 54 ~ did not show a wide manifestation on winter wheat crops; the test material was not differentiated by resistance to them . Since signs of diseases on winter wheat crops depend on meteorological factors, and disease intensity varies from year to year, a reliable estimate of collection and breeding material can be obtained only provided a minimum three-year study on infectious or provocative backgrounds of pathogens. After all, even if an infection is introduced and optimal conditions for its development are created, levels of infectious backgrounds vary from year to year. Every year the number of samples in nurseries of resistant forms reaches 100-150.
On the basis of the results of three-year studying sources of resistance were identified. Thus, over the period of 2011-2013 among the collection samples 6 sources of individual resistance were identified, of which 4 sources -to septoriosis (L-25-OKH, Lutsina, Omskaya 6, Unikum), 2 sources -to head smut (Tarasovskaya/Belotserkovskaya, Polukarlik); 4 sources of group resistance to septoriosis and powdery mildew (KS 91112, IPM 296-06, Alana, Zarytsya); and 1 source of group resistance to powdery mildew and head smut (Ulya). The immunological parameters of the selected sources of resistance are summerized in Table 1.
Subsequently the sources selected will be crossed with susceptible varieties for hybridological analysis in F 2 and estimation of their donor properties, ie their ability to propagate the resistance trait to offspring.
Another focus of work with the selected sources and donors of disease resistance is hybridizing them with highly productive and varieties adapted to the growing conditions with following selections from hybrid generations. For example, in 2013 seven constant lines, which were the best resistant to diseases according to the field counts, were selected from hybrid populations F 6 -F 8 , and the structural elements of their yield were analyzed ( Table 2).
These lines are submitted for expert examination to the National Centre of Plant Genetic Resources of Ukraine (NCPGRU) with the following characteristics: -LCH -115-2012 -Podolyanka/AS-182 -resistance to powdery mildew of 6 points, resistance to septoriosis of 7 points, the capacity yield at the rate of the standard Podolyanka, 1000-seed weight is higher than that of the standard.  * -According to the data of trials at the Ustimovskaya Experiment Station , 2011 and 2012.
In 2011 the last 4 lines were tested in the Kharkiv and Poltava regions (Ustimovskaya Experiment Station); the data of these tests are summerized in the characterization of the lines.
After undergoing expert review in the Laboratory of Genetic Resources of Cereals the line LCH 821/10 was registered in NCPGRU and itemized under No. UA0108203 in the National Catalog and under Rregistration Certificate No. 1176; the line LCH 117/12 -UA0108195 and No 1175, respectively, d/d 25 February 2014. The lines registered are new valuable source material for breeding, since they combine group resistance to leaf diseases (7 points ), resistance to biotic factors (frost resistance of 6.5-7 points) and high yield capacity (790-800 g/m 2 ).
Conclusions. Thus, as a result of immunological assay conducted on artificial infectious and provocative backgrounds for the last three study years (2011-2013) sources of individual (6 samples) and group (5 samples) resistance to leaf diseases and head smut were identified. By hybridization and multiple selections on infectious and provocative backgrounds seven new lines with a complex of valuable economic characteristic, which can be used as improved donors in breeding programs, were created. The two best lines are registered in NCPGRU (Certificate Nos. 1175, 1176 d/d 25.02.2014).
Therefore, the search for new sources of resistance to diseases, determination of their donor properties and creation on their basis of new source material with a complex of valuable features are the mainstream directions of research.
Material and Methods. The study material was winter wheat collection samples and wheat lines F 6 -F 7 derived from previously identified sources of resistance. The samples were immunologically characterized in the infectious provocative nursery of scientific crop rotation at the Plant Production Institute nd. a V.Ya. Yuryev of NAAS of Ukraine. Sowing was carried out in the optimal time frame for the culture (for leaf diseases) and later (to provoke head smut infection in plants) with hand drills, on 3-5 rows, each 1 m long, with the row spacing of 15-20 cm and bare fallow as a predecessor. Counts of affected plants and determination of the resistance of samples under investigation were carried out according to the scales and procedures given in the methodological recommendations. Results. On the basis of the results of three-year studying sources of resistance were identified.
Thus, over the period of 2011-2013 among the collection samples 6 sources of individual resistance were identified, of which 4 sources -to septoriosis (L-25-OKH, Lutsina, Omskaya 6, Unikum), 2 sources -to head smut (Tarasovskaya/Belotserkovskaya, Polukarlik); 4 sources of group resistance to septoriosis and powdery mildew (KS 91112, IPM 296-06, Alana, Zarytsya); and 1 source of group resistance to powdery mildew and head smut (Ulya). Seven constant lines, which were the best resistant to diseases according to the field counts, were selected from hybrid populations Winter wheat, source material, resistance, sources, samples, lines, hybridization