Photosynthetic efficiency of sorghum (Sorghum bicolor) under the effect of elements of cultivation technology

Abstract

Purpose. To determine photosynthetic efficiency of Sorghum bicolor hybrids under the foliar application of microfertilizers and plant growth regulators.
 Methods. The research was carried out in 2019–2021 in the experimental site of the Scientific Research Center of the Bila Tserkva National Agrarian University (Kyiv region). Sorghum hybrids 'Brigga' and 'Yutami' wereused in the study. The sowings were treated during the growing season with microfertilizers Alfa-Grow-Extra, 2 l/ha (1st treatment in the 5-leaf stage, 2nd treatment in the 9-leaf stage, 3rd treatment in the emergence of panicle stage) and Intermag-Corn, 2 l/ha (1st treatment in the 5-leaf stage, 2nd and 3rd treatments with an interval of 7 days) and plant growth regulators Regoplant, 50 ml/la and Stimpo, 20 ml/ha in the in the 5-leaf stage.
 Results. It was established that in the panicle emergence stage, the best indicators of the leaf area in the hybrid 'Brigga' were obtained with foliar application of the microfertilizer Intermag-Corn in combination with the growth regulator Regoplant – 49.1 thousand m2/ha, in 'Yutami' – with the application of Intermag-Corn in the composition with Regoplant or Stimpo – 52.9 thousand m2/ha, while in the control this figure was 48.1 thousand m2/ha. At the time of full grain maturity, 14.49 and 16.68 t/ha of dry matter were formed by the hybrids 'Brigga' and 'Yutami' in the treatment with Alpha-Grow-Extra with Stimpo growth regulator. In the interstage period from panicle emergence to flowering, the photosynthetic potential of the hybrid 'Brigga' was on average 0.44 thousand m2/ha × days, in 'Yutami' – 0.52 thousand m2/ha × days. In the interstage period from flowering to full maturity, in the hybrid 'Brigga' when treated with microfertilizer Alpha-Grow-Extra in combination with growth regulator Stimpo, the net productivity of photosynthesis was 3.33 g/m2 of dry matter per day, and in the case of using microfertilizer Intermag-Corn in combination with Stimpo growth regulator – 3.14 g/m2 per day. In the case of growing the 'Yutami' hybrid under foliar application of Alpha-Grow-Extra or Intermag-Corn, the best indicators of net photosynthesis productivity were obtained in the combination with Stimpo growth regulator – 3.19 and 3.19 g/m2 per day of dry matter, respectively.
 Conclusions. The studied elements of the technology, especially foliar application of microfertilizers, effectively influenced the course of photosynthesis processes and, accordingly, ensured the formation better indicators of sorghum productivity.