Registration of WA-HT1, a Camelina Line with Resistance to Residual Levels of ALS Inhibitor Herbicides

Camelina (camenlina sativa L. Crantz) is highly sensitive to soil residual levels of many acetolactate synthesis (ALS) inhibitor herbicides. Other crops with resistance to these herbicides have been developed through mutation. Development of camelina with this resistance would allow greater flexibility for the crop in rotation with other crops. The SM4 (sulfonylurea mutant 4) line, previously derived by mutagenesis, showed increased resistance to both imidazolinone and sulfonylurea herbicides. The mutation was controlled by a single semidominant gene and was derived in the 'Cheyenne' background. Progeny plants with good vigor from the SM4 variant were crossed to the plants from cultivar Calena, which has consistently performed well in Camelina trials the US Pacific Northwest. Lines from this cross that had good seed yields and were homozygous for the gene controlling resistance were advanced by pedigree selection at Washington State University. Selection for seedling vigor, seed yield, and oil content resulted in the F-6-derived line WA-HT1 (GP-37, PI 683517). The WA-HT1 line is severely stunted if specified field rates of imazamox (Beyond) herbicide is directly applied but is tolerant to residual levels of the herbicide encountered from carryover of previous applications. Use of the WA-HT1 line will reduce the risk associated with growing camelina in crop rotations that use group 2 herbicides.