STUDIES ON GENE FLOW FROM HERBICIDE RESISTANT TO WEEDY SUNFLOWER

Gene flow is a main concern associated with the use of herbicide resistant sunflower crops because it could transfer herbicide resistance traits to weedy sunflower. In order to estimate potential gene flow from imazamox and tribenuron-methyl resistant sunflower hybrids to weedy sunflower, field experiments and DNA analysis were conducted. The progeny of weedy sunflower which grown near imazamox (WS1) and tribenuron-methyl (WS2) resistant hybrid in previous experiments were used. In the field experiment, recommended rates of imazamox and tribenuron-methyl were applied to WS1 and WS2, respectively, and plants surviving were recorded. Herbicides effect on fresh weight of survived plants were also determined. The presence of mutations responsible for sunflower resistance to herbicides (imazamox and tribenuron-methyl) checked based on DNA analysis of selected survived plants. Percentage of survived plants in field experiment was recorded at maturity and depend on weedy sunflower accession (WS1 or WS2) and distance of their mother plants from resistant sunflower hybrid in previous experiment and was higher for WS2 (50.25%) than for WS1 (24.50%). As DNA analysis were not confirmed the presence of the point mutations responsible for sunflower resistance to imazamox and tribenuron-methyl.