Purpose. Comparative studies of the photosynthetic apparatus of winter wheat varieties of modern and earlier breeding in the relation to their productivity. Methods. Field, pot experiment, biometrical, gas analysis, analytical and statistical ones. Results. It is found that the modern high-yielding winter wheat varieties have a higher rate of flag leaf photosynthesis during generative period of development, particularly at grain filling period, improved ability to store assimilates in stem and effectively use them later for grain growth. The modern varieties form crop canopy with greater leaf area and chlorophyll indexes and larger photosynthetic capacity and maintain functional activity of photosynthetic apparatus longer at the end of the growing season. Conclusions. The superiority for grain productivity of modern high-yielding wheat varieties, originated from the Institute of Plant Physio­logy and Genetics, NAS of Ukraine, over varieties released before the “green revolution”, results from increased capacity and durability of functioning the crop photosynthetic apparatus, higher CO2 assimilation rate and optimization of source-sink relations in whole plant.

Oats technological indices have been analyzed. Influence of growing conditions on natural weight, kernel size, and hoodness is established. The study summary indicates essential dependence of natural weight and hoodness and precipitation at the stage of grain formation in coated grain oats varieties. Moisture supply in the period of grain formation essentially influenced the percentage of coated grains formation and natural weight score in naked grain varieties. Morphometric analyzes of oats caryopsis was completed using the method of machine vision. Correlation between technological indices and morphometric cha­racteristics of naked and coated grain of oats was determined. Also, essential dependence of hoodness on 1000 seeds weight and the lack of essential correlation with morphometric characteristics of the calliopsis were established. Calliopsis width essentially influenced the weight of 1000 seeds. Metric indices of naked grain oats calliopsis exposed close correlation with kernel size and natural weight. Weight of 1000 seeds exposed essential varietal distinctness and was determined by genetic peculiarities of varieties