| Abstrakt: |
Aim of this study was to determine the efficiency of developing and forming the productivity elements of sorghum crops, selected in Ukraine, with the purpose of optimizing their productivity. Field studies were conducted in the soil and climatic conditions of the Central Forest-Steppe zone of Ukraine in 2012-2018 within the DPDH Salyvinkivske and at the Bila Tserkva Research and Selection Station of the Institute of Bioenergy Crops and Sugar Beet of the National Academy of Agricultural Sciences of Ukraine. Sorghum varieties of domestic breeding were used for the studies: common sorghum (bicolor): Odeskyi 205, Lan 59 and sweet sorghum: Huliver, Dovista. The following experimental factors were investigated: Factor A: Hybrid. Factor B: The phase of foliar fertilization: growth and development scales for sorghum plants according to BBCH 21-24, 31 and 37, according to Kuperman BBCH, IV and VI-VII. Factor B: Treating the plants with Vympel 2 growth stimulator (0.5 l/ha). The differences between the investigated scales and common features were determined via the comparison of phenological phases and organogenesis stages based on the specificities of organ formation of sorghum plants and using the results of morphophysiological analysis. The results of the comparison of growth and development scales for sorghum crops demonstrated that Feekes scale and the scale of Keller & Baggiolini are derivatives of the unified extended growth and development scale (BBCH) and describe the growth and development of sorghum plants in a less detailed way. Thus, the experimental studies were conducted with the consideration of BBCH and Kuperman scales which uniformly highlight the main growth and development stages of plants. It was also determined that from I to VII stage of organogenesis Kuperman scale classifies growth and development stages of sorghum crops based on the state of the apical dome and the initiation of vegetative and reproductive organs of the plant on it. Thus, it is difficult to determine early stages accurately without the morphophysiological analysis. Foliar application of Vympel 2 growth stimulator on microstages 21-24 by the unified extended BBCH scale promoted faster growth and development of grain sorghum plants and the formation of higher grain productivity. For instance, Odeskyi 205 variety produced the yield of 5.26 t/ha, and the yield of Lan 59 was 5.70 t/ha. The introduction of a growth stimulator at the third stage of organogenesis according to Kuperman also contributed to the increase in comparison with the control variants, but the yield for the studied varieties was 5.10 and 5.56 t/ha. Similar introduction of the growth stimulator on the fields of sweet sorghum hybrids contributed to better productivity indices and quality of the received produce in comparison with the control variants. For instance, in case of applying Vympel 2 growth stimulator to Huliver hybrid, its biomass yield on microstages 21-24 was 93.5 t/ha, the dry matter harvest was 18.9 t/ha and the overall sugar content in the stem juice was 14.9 %, while these indices for Dovista hybrid amounted to 98.8 t/ha, 19.8 t/ha and 15.7 % respectively. After the introduction of a growth stimulator on the third stage of organogenesis according to Kuperman, the biomass yield of Huliver hybrid was 92.1 t/ha, the dry matter harvest - 18.4 t/ha and the overall sugar content in the stem juice - 14.8 %, while those of Dovista hybrid were 97.3 t/ha, 19.3 t/ha and 15.6 % respectively. The results of comparing growth and development scales for sorghum crops demonstrated the suitability of BBCH and Kuperman scales to describe the state of plants and good agreement between them. However, the identification according to the scale of F.M. Kuperman on early stages of sorghum growth and development is too complicated in practice, requiring specific skills and morphophysiological analysis. Such scales as Keller & Baggiolini and Feekes are derivatives of BBCH scale with the specification of some phases of plant growth and development. To stimulate growth processes, foliar fertilization on early stages of sorghum growth and development should be done based on the data of plant growth and development microstages. For instance, after the introduction of Vympel 2 growth stimulator on microstages 21-24 according to BBCH, the increase in the yield of grain sorghum, compared to its application on the third stage of organogenesis, was by 0.14-0.16 t/ha, and the increase in the biomass yield of sweet sorghum was 1.6 t/ha respectively. Foliar fertilization on later stages of growth and development of grain sorghum and sweet sorghum, aimed at forming higher quality of the produce, does not require accurate identification of microstages of plant growth and development; thus, it is possible to determine the time of applying stimulators efficiently both based on the data of BBCH scale and on the scale, developed by F.M. Kuperman. [ABSTRACT FROM AUTHOR] |
