EVALUATION OF CORN HYBRIDS BY THE COEFFICIENT OF VARIATION OF INDIVIDUAL PRODUCTIVITY INDICATORS

The aim of the study was to determine the degree of variability in quantitative traits characterizing the components of individual productivity in mid-early and medium-maturity maize hybrids and to assess their stability across growing years. The study was conducted in 2024–2025 under the conditions of the Agronomic Research Station, a separate subdivision of the National University of Life and Environmental Sciences of Ukraine, located in Bila Tserkva District, Kyiv Region. The research material comprised maize hybrids belonging to the mid-early (FAO 200–299) and medium-maturity (FAO 300–399) maturity groups. The following traits were studied: ear diameter, ear length, number of kernel rows, and number of kernels per row. To assess trait variability, the arithmetic mean, standard deviation, and coefficient of variation were determined. The results showed that the studied hybrids exhibited different levels of variability in individual components of ear structure. The most stable trait was the number of kernel rows: in most cases, the coefficient of variation did not exceed 10%, indicating a high degree of uniformity among hybrids for this trait. The number of kernels per row was characterized predominantly by low and moderate levels of variability. A similar pattern was observed for ear length, although the range of variation among individual genotypes was somewhat wider. The most contrasting trait in terms of variability was ear diameter. In 2024, the coefficient of variation in the mid-early maturity group ranged from 2.79% to 48.68%, with the maximum value recorded for hybrid SDT 9. In 2025, the overall variability of this trait was lower. This indicates different genotype responses to growing-year conditions and the possible manifestation of genotype × environment interaction. A consistently low level of variability across all studied traits over the two-year period was established for hybrid SDT 25 (FAO 380), whereas SDT 14, SDT 19, and SDT 22 exhibited stable values for three traits simultaneously. The results confirm the importance of comprehensive, multi-year evaluation of maize hybrids for identifying genotypes with a high degree of uniformity and stability in the expression of economically valuable traits, as well as for developing a hybrid model with predetermined parameters.