Influence of the light regime on the growth and development of winter wheat in agrocenosis of the Right Bank Forest Steppe of Ukraine

Abstract

The activity of winter wheat plants is largely determined by the presence of optimal light regime, which, of course, is due to both meteorological factors and the influence of seeding rate, which depends on the density of stems. The urgency of the research is due to the search for new approaches to the development of elements of technology for growing winter wheat, taking into account the soil and climatic conditions of the right-bank Forest-Steppe of Ukraine.

Winter wheat is one of the oldest and most widespread crops on earth. Thus, the share of land under crops of this crop was less than 25% of the sown area. In the conditions of climate change in Ukraine with the increase of positive and active temperatures during the growing season, reduction of precipitation, spread of soil and air drought, the role of varieties in maintaining its stable productivity and further increasing their productivity will increase significantly. A study of the influence of sunlight on the growth and development of winter wheat plants. It is proved that the growth rate of plants also depends on the intensity of light. It is  noted that the plants grow the fastest in the morning, the minimum growth rate is in the evening. In this regard, in full accordance with the above data, the reaction of winter wheat to the spectral composition of the rays. 

Numerous studies have shown that essentially no anatomical or morphological properties of plants, as well as the differentiation of aboveground parts, which is observed in natural growth conditions, remains unchanged under direct sunlight. The rate of plant growth also depends on the intensity of light. Plants grow more slowly at night than at night, as low light significantly slows growth. The plants grow the fastest in the morning, the minimum growth rate is in the evening. That is why morning and evening light is most favorable for plant growth and development. In this regard, in full accordance with the above data, there is a reaction of wheat to the spectral composition of the rays. For photosynthetic activity, wheat makes the best use of the red-orange part of the spectrum

Field research on the topic of the dissertation was conducted during 2019-2021 on the basis of the research farm «Agronomichesky» of Vinnytsia National Agrarian University in the village of Agronomichne, Vinnytsia district, Vinnytsia region. 

The aim of the study was to study the influence of light regime on the growth and development of winter wheat hybrids depending on fertilizer backgrounds and seeding rates in agrocenoses of the Right Bank Forest-Steppe of Ukraine. High-yielding Patras and Tobac hybrids were used in the studies. Growing technology for winter wheat plants in research areas is generally accepted for soil and climatic conditions of the right-bank Forest-Steppe of Ukraine. 

Therefore, for photosynthetic activity, wheat makes the best use of the red-orange part of the spectrum. It was determined that the best illumination in wheat cenoses in the tube exit phase was at the sowing rates of 1.5 million seeds / ha in 2020 (2550 lux). It is proved that in the period of milk ripeness the illumination of plants at different seeding rates was significantly lower, because in this period the leaf surface area is the highest. Therefore, during this period, the greatest penetration of light into the middle of the stem was observed at the seeding rate of 3 million seeds / ha. Thus, studies have shown that the light in wheat cenoses, both in the tube phase and in the milk ripeness phase, largely depends on the distribution of plants in the area, which is related to the seeding rate. Analysis of variance showed that the most significant share of the impact on illumination in both the tube exit phase and the milk ripeness phase was the seeding rate: in the first case it was 46%, in the second –  49%. The conditions of the year also had a significant impact on the stages of the growing season, they were also a significant share, and their impact was estimated at 32 and 36%, respectively.

Thus, studies have shown that the light in wheat cenoses, both in the tube phase and in the milk ripeness phase, largely depends on the distribution of plants in the area, which is related to the seeding rate.