GROWTH, DEVELOPMENT AND SEED PRODUCTIVITY OF SPOTTED MILK THISTLE DEPENDING ON THE APPLICATION OF RETARDANTS, TIMING AND METHODS OF SOWING

The influence of retardants, terms and methods of sowing on the growth, development and seed productivity of the thistle plant in Podillya is analyzed in the article. The terms (with soil temperatures of 10-110 С, 12-130 С and 14-150 С) and sowing methods (solid – 15 cm and wide row – 45 cm) were research. It was established the influence of pre-sowing treatment of seeds with retardants Chlormequatchloride and Tebuconazole, different terms and methods of sowing on the productivity of thistle plant. Phenological observations and biometric measurements were performed. The dynamics of green mass growth and seed productivity depending on the terms and methods of sowing, and application of retardants are determined. It was found that the growth inhibitors Chlormequatchloride and Tebuconazole resulted to increasing of the seed germination and survival of milk thistle plants. Due to the unstable conditions of the temperature regime of the Podillia region, the period of seed germination is quite long (12-16 days) and the seedlings are uneven, so the optimal sowing periods of the thistle culture are intended to the increasing of germination energy and simultaneity seedlings. The survival of plants in the wide-row sowing method (i.e., with a larger area of nutrition) exceeded this indicator for a continuous sowing method. All investigated factors: retardants, method and time of sowing influenced on the survival of thistle plants at the end of vegetation. The highest survival of plants of this culture was found with the use of Tebuconazole (0,5 %) during the third sowing period. The wide-row placement of plants in plots (row spacing 45 cm) caused better plant survival during vegetation period compared to continuous sowing method (row spacing 15 cm). The use of the preparations Chlormequatloride and Tebuconazole influenced on the biometric characteristics of the crop – linear growth of plants increased, the number of leaves, shoots and inflorescences grew. These indices of growth and development of the culture increased in the wide-row sowing method (compared to continuous sowing), as well as a larger number of shoots were formed, on which full baskets with seeds grew. In the process of ontogeny of the thistle spotted the aboveground organs changed their ratio. The largest part of the leaves of this culture is noted in the budding phase for sowing of the second term. The opposite tendency was observed in the change in growth of shoots: in the budding phase their mass was greatest in early sowing. Pre-sowing seed treatment with retardants, the third sowing term in a wide-row way led to the increase of the seed productivity of milk thistle. The highest germination of milk thistle seeds was in the third term of the sowing at a soil temperature of 14-15° C, especially with pre-sowing treatment of the seeds with an aqueous solution of 0,5 % Tebuconazole.