Inheriting the resistance of sunflower to tribenuron methyl under insufficient humidification in the southern Steppe of Ukraine

Abstract

Aim. This study aimed to investigate the inheritance of resistance to sulfonylurea herbicides in sunflower under conditions of insufficient humidification in the southern Steppe of Ukraine. Methods. Isolation, castration, hybridization, herbicide application (Granstar Pro 75 % w.g., containing tribenuron methyl as the active substance (a.s.)), evaluation of herbicide resistance, and statistical analysis of the acquired data. Results. The investigation into the inheritance of resistance to sulfonylurea herbicides involved the utilization of both resistant (SURES-1, OS 1099 V, OS 2017 V) and non-resistant (Od 1002 B, Od 1318 V, OS 1295 V) sunflower genotypes. Through crossing, four F1 hybrid combinations were generated, namely OS 2017 V × OS 1099 V, SURES-1 × Od 1002 B, SURES-1 × Od 1318 V, and Od 1318 V x OS 1295 V. Subsequent treatment of F1 plants with the herbicide Granstar Pro 75 % w.g. revealed that three combinations (OS 2017 V × OS 1099 V, SURES-1 × Od 1002 B, SURES-1 × Od 1318 V) exhibited complete resistance to the herbicide. In the second generation, following herbicide treatment, the hybrid combinations SURES-1 × Od 1002 B and SURES-1 × Od 1318 V displayed segregation into resistant and non-resistant plants. Conversely, the plants in the combination OS 2017 V × OS 1099 V maintained complete resistance to the herbicidal effects. Conclusions. The investigation, conducted in the challenging climatic conditions of the southern Steppe of Ukraine, demonstrated complete resistance to sulfonylurea herbicides in three hybrid combinations of both F1 and F2 generations. Notably, the combination OS 2017 V × OS 1099 V exhibited uniform resistance throughout the second generation, devoid of segregation. Moreover, the results of F2 segregation analysis in the SURES-1 × Od 1002 B and SURES-1 × Od 1318 V populations indicated that resistance to tribenuron methyl is primarily governed by the presence of a dominant gene allele. These findings offer valuable insights for the development of sunflower hybrids with enhanced herbicide resistance, particularly in regions with adverse climatic conditions.