THE INFLUENCE OF THE PLANT PROTECTION SYSTEM ON THE YIELD STRUCTURE OF CORN HYBRIDS WHEN GROWN UNDER IRRIGATION CONDITIONS IN THE SOUTH OF UKRAINE

Abstract

The purpose of the article to investigate the effect of plant protection systems on the elements of productivity of corn hybrids of different FAO groups when grown under irrigation conditions in the south of Ukraine. Research methods. The research was conducted in 2017–2019 at the experimental field of the Institute of Irrigated Agriculture of the National Academy of Sciences (now the Institute of Climate-oriented Agriculture of the National Academy of Sciences). Factor A – corn hybrids of different FAO groups: Stepovy (FAO 190), Skadovsky (FAO 290), Ingulsky (FAO 350), Chongar (FAO 420), Arabat (FAO 430) selected by the Institute of Irrigated Agriculture of the National Academy of Sciences. Factor B – protection system: control, water treatment; biological; chemical; integrated The corn cultivation technology was generally accepted for irrigated conditions and met the requirements of the corn production technology for the agro-ecological conditions of the Steppe zone of Ukraine. Research results. The growth of the indicator "weight of 1000 seeds" up to 308 g was recorded in the plots with the Arabat hybrid (FAO 430) under integrated plant protection. Its decrease by 1.6 times (to 187 g) was manifested in the Stepovy hybrid (FAO 180), which was grown without plant protection. The average mass of 1,000 grains (246, 252 g) had biological and chemical plant protection, and the difference between them was insignificant – only 2.4%. This indicator of grain size was minimal in areas without plant protection (control), where it was equal to 235 g. The largest weight of 1,000 grains reached under integrated plant protection was 264 g, which exceeded the control by 12.3%, and variants with biological and chemical plant protection by 7.3 and 4.8%, respectively. Adherence to integrated plant protection with the late-ripening Arabat hybrid (FAO 430) led to a significant increase in grain yield compared to the untreated control by 33.8% (up to 11.12 t/ha). It was established that among the corn hybrids studied in the field experiments under irrigation, on average, the highest yield (9.50–10.31 t/ha) in terms of factor A is formed by mid-late and late group hybrids Chongar (FAO 420), Arabat (FAO 430). Conclusions. The Arabat hybrid (FAO 430) had the maximum number of grains on one cob – 597 pcs. under integrated plant protection, and in the early-ripening Steppovy hybrid (FAO 180) without plant protection, it was significantly reduced by 48.3%. The weight of 1,000 grains increased to 308 g in the version with the Arabat hybrid (FAO 430) with integrated plant protection, and for the cultivation of the Stepovy hybrid (FAO 180) without plant protection, it decreased by 1.6 times (to 187 g). On average, over the years of research, it was established that hybrids of early, mid-early, and mid-ripening groups provided the maximum grain yield in compliance with integrated plant protection. For individual hybrids Stepovy (FAO 180), Skadovsky (FAO 290), the use of biological plant protection significantly increased grain yield by 7.9–14.3%. The medium-ripe Ingul hybrid (FAO 350) also significantly increased the grain yield by 2.66 t/ha with integrated plant protection when compared with the Stepovy hybrid (FAO 180). Regarding the Chongar hybrid (FAO 420), on average over the years of research, the grain yield in the control version and with biological protection was practically the same and amounted to 9.05 and 9.33 t/ha, respectively. The maximum grain yield at the level of 9.50–10.31 t/ha was formed by mid-late hybrids Chongar (FAO 420) and Arabat (FAO 430).