ПРОЯВ ГОСПОДАРСЬКИХ ОЗНАК ТРИЛІНІЙНИХ ГІБРИДІВ СОНЯШНИКУ, СТІЙКИХ ДО ГЕРБІЦИДІВ ГРУПИ СУЛЬФОНІЛСЕЧОВИН

The creation of specialized sulfonylurea herbicide-resistant sunflower hybrids ensured reliable protection of this crop fields against dicotyledonous weeds during the post-emergence period. The issue of sulfonylurea resistance levels in three-line hybrid combinations, where at least two parental components are resistant, remains insufficiently studied. Our purpose was to evaluate valuable economic feature expression levels in sulfonylurea herbicide-resistant three-line sunflower hybrids. To accomplish this purpose, we determined 1) the phytotoxic effect of herbicide Gold Star WDG on five three-line sunflower hybrids originated from two resistant and one susceptible parents; 2) the variability of valuable economic features of the hybrids affected by the herbicide in different agro-climatic zones of Ukraine. The study was carried out at the Yuriev Plant Production Institute of NAAS (Kharkiv) and the Institute of Oilseed Crops of NAAS (Zaporizhzhia) in 2021-2022. The herbicide was supplemented with surface-active agent (SAA) Tandem 0.3 L/ha and applied at doses of 50 g/ha (2021) and 35 g/ha (2022) in the phase of 4-6 (2-3 pairs) true leaves. The operating fluid consumption was 200 L/ha. There was no 100% resistance to the herbicide in any experiment. The percentage of resistant plants in 2021 varied from 21.9 to 60.2%, in 2022 - from 33.3 to 78.1%. On average across the hybrids, the proportion of resistant plants increased from 42.3% in 2021 to 51.0% in 2022. Herbicide treatments significantly reduced seed yields and oil content in seeds of most hybrids compared to the control. The smallest yield loss (-0.26 t/ha) was recorded for hyb. 'Skh 81 А' / 'Kh 82 B'//'Kh 201 V' treated with 50 g/ha of Gold Star WDG. The smallest decrease in the oil content in seeds (-0.69%) was observed in hyb. 'Skh 1006 А' / 'Kh 81 B'//'Kh 201 V' treated at 50 g/ha. In the experiments of the IOC NAAS in the northern steppe, the tested hybrids yielded less than or similarly to the reference, classical hyb. 'Yason', depending on the weather conditions. The hybrids were classed as early ripening. As to oil content in seeds, they were superior to the reference hybrid. As to plant height, plants of the hybrids under investigation were mostly as tall as the reference ones. Conclusions. The three-line hybrids derived from two resistant parental components had reduced levels of expression of valuable economic features when treated with herbicide Gold Star at doses of 50 and 35 g/ha. However, expression of these features should be assessed individually for each hybrid combination. The studied hybrids are competitive in terms of expression levels of valuable economic features; however, additional studies of other regimens of sulfonylurea herbicide application are required. [ABSTRACT FROM AUTHOR]