There is no cross resistance. For example, varieties with the STS 2 herbicide resistant gene but lacking the Roundup Ready gene will die if sprayed with labelled Roundup branded herbicides. Likewise, corn hybrids with the Liberty Link 3 gene for resistance to Liberty 3 herbicide will die if treated with labelled Roundup branded herbicides. When growers choose to plant a herbicide-resistant seed, it is vital to know which variety is planted on which acre in order to match herbicide programs. Evaluating yield potential.
Yield is determined by many factors.
Besides the genetic potential of the seed, defensive traits, such as Phytophthora root rot or soybean cyst nematode resistance, can have a dramatic impact on a variety's performance. This is especially true when these pests are present in high concentrations. In addition, weed competition can reduce yields significantly. Because of these factors, the best opportunity to maximize return per acre is to match carefully seed and herbicide programs to each acre. In some cases, this may require a seed with a herbicide-resistant trait.