VARIETAL SPECIFICITY OF OPTO-BIOLOGICAL PROPERTIES AND PHYTOMETRIC PARAMETERS OF WINTER WHEAT CROPS

Identification of varietal specificity of opto-biological properties of field crops is necessary for adequate interpretation of satellite images, rapid determination of phytometric parameters of crops, indication of the level of their development and justification of corrective technological solutions. The aim of the research was to evaluate the opto-biological properties and phytometric parameters of diverse biological varieties of winter wheat; identify their relationship and inter-variety variability in high-tech reference crops based on satellite and ground monitoring. Field studies were conducted in 2019-2020 on the site of competitive ecological variety testing laid on the experimental field of the Orenburg State Agrarian University in the zone of the southern steppes of the Orenburg Cis-Urals (Preduralye). During the study, we found that agrocenoses of different winter wheat varieties differ markedly in opto-biological properties expressed in normalized difference vegetation index (NDVI) values. Varieties ‘Grom’, ‘Don 95’, ‘Bystritsa’, ‘Spartak’, ‘Stanichnaya’ and ‘Sintetik’ were characterized by the lowest average NDVI values during the growing season (0.57-0.59). Higher NDVI values (0.67) were observed in the crops of ‘Zhemchuzhina Povolzhya’, ‘Kolos Orenburzhya’, ‘Orenburgskaya 105’, ‘Rifey’ and ‘Pionerskaya 32’ varieties. The variability between the varieties according to the lowest (0.51 – ‘Grom’, 0.52 – ‘Don 95’) and the highest (0.69 – ‘Kolos Orenburzhya’, 0.70 – ‘Pionerskaya 32’, 0.69 – ‘Orenburgskaya 105’) NDVI values during the maximum assimilation apparatus development reached 0.17-0.19 units (phase of full spring tillering). By the heading, when NDVI was 0.78–0.79 and 0.85 units, respectively, this difference somewhat leveled but, in general, remained significant – at the level of 0.08-0.11 units (10.9–14.9 %). The largest leaf area (30 thousand m2/ha) was typical for the crops of ‘Saratovskaya 17’, ‘Kolos Orenburzhya’, ‘Orenburgskaya 105’, ‘Rifey’ and ‘Pionerskaya 32’. There was no direct inter-variety relationship between the leaf area and NDVI of winter wheat crops (R 2= 0.38).