Biometric parameters of the assimilating surface of sunflower plants

Abstract

The growth, development of sunflower plants and the for- mation of their leaf apparatus determine the amount of accu- mulated dry matter, affect crop productivity and depend on a number of regulated and unregulated factors. The aim of the article was to identify the influence of soil and climatic con- ditions of the years of research, genetic features of hybrids and technological techniques on the growth, development and formation of the assimilating apparatus of sunflower hybrids of different maturity groups. Methods. Field research was conducted in 2023-2024 in the conditions of the Ternopil region in accordance with generally accepted methods. The experiment was established using the split-plot method. The area of the sown plot was 60 m2, the accounting plot was 42 m2 with four-fold repetition. The predecessor in the experi- ment was winter wheat. During the growing season of sun- flower plants, phenological observations of plant growth and development were conducted.Results. The obtained research results showed that as the plants grew and developed, the leaf surface area increased. The maximum values were obtained during the flowering period of plants, which corresponded to 65-68 microstages of the ВВСН. Later, a decrease in the indicator was noted. This trend was observed in all hybrids that we studied, regardless of the maturity group. The highest indi- cators were obtained in the variant using N80P80K120, which varied from 40.8 to 45.6 thousand m2/ha. In the early matu- rity group, the parameters were from 40.8 to 41.4 thou- sand m2/ha, medium-early – 42.2-42.4 thousand m2/ha, medium – 44.9-45.6 thousand m2/ha. Conclusions. The maximum assimilating surface was formed by the hybrid of the middle ripeness group P64LL155 45.6 thousand m2/ha and the variant with the use of N80P80K120. A direct correla- tion was established between the area of plant blades and yield with a correlation coefficient of 0.978.