Features of identification of stages of growth of grain sorghum

Abstract

Purpose. To study the stages of growth of grain sorghum on the example of the application of the Vanderlip and Reeves scale for the study of sorghum varieties of domestic selection.Methods. Field research was conducted during 2012–2018 in the soil and climatic conditions of DP DG “Salyvinkivske”, located in the Right-Bank Forest-Steppe Zone of Ukraine. Grain sorghum varieties of domestic selection were used for research and the peculiarities of the manifestation of growth stages were identified visually and on the basis of the peculiarities of sorghum plant organ formation at the embryonic level.Results. The Vanderlip and Reeves scale describes the stages of sorghum growth on a scale from 0 to 9 and is based on the visual manifestation of the traits. It is determined that at the stage of emergence (Stage 0) the influence of environmental factors and agronomic techniques is critical. But in phase 3 of the leaves (Stage 1) the plants cannot compete effectively with the weeds. In phase 5 of the leaves (Stage 2) the plants are sensitive to the negative effects of pests and weeds. Also, lack of nutrients, moisture or drought can significantly reduce yields. Differentiation of the growth point (Stage 3) corresponds to the period of rapid growth of sorghum plants, and therefore the lack of mobile forms of nitrogen can cause growth restrictions. But during the appearance of the flag leaf (Stage 4) on the level of productivity of sorghum plants are factors of lack of sufficient nutrients and moisture in the soil, it is necessary to continue pest control. During the ejection of panicles (Stage 5) and flowering (stage 6), plants react most critically to the provision of moisture and the onset of the driest conditions of the growing season. At the stage of milk ripeness (stage 7), drought slows down the rate of grain filling, and excessive moisture contributes to the development of diseases.Conclusions. Using the Vanderlip and Reeves scale to identify growth stages does not require special knowledge of the peculiarities of the formation of sorghum at the embryonic level. At the same time, it is comparable to other scales and evenly covers the main phases of plant growth and development.