THE DYNAMICS OF A DRY MATTER ACCUMULATION IN THE INITIAL PERIOD OF GROWTH OF FOUR VARIETIES OF THE "STAY-GREEN" TYPE OF MAIZE (ZEA MAYS L.)

The aim of the study was to determine the impact of weather conditions (temperature, precipitation) on the dynamics of dry matter accumulation and nitrogen nutritional status of maize plants in the type of stay-green". Four varieties were evaluated: NK Cooler, Delitop, NK Gazelle, NK Ravello. Thermal conditions and humidity in the period from sowing to the phase of 5-6 leaves (BBCH 15/16) shaped the dynamics of dry matter accumulation and nitrogen nutritional status of plants. The differences were found in tested varieties of stay-green" in terms of the dynamics of initial growth, expressed by the dynamics of dry matter accumulation and their nitrogen nutritional status. In most of the analyzed characteristics, the variety of NK Cooler was characterized by favorable values of these characteristics, as compared to other varieties. The genetic variation of tested varieties is derived from the heterosis cultivation process of F1 hybrids. Currently, cultivated maize varieties (including stay-green") are F1 hybrids characterized by identical genotype and varietal differences arise from components of parental hybrid genotype (paternal and maternal), as presented in the paper.