Molecular characterization of imidazolinone-resistant Brassica rapa × B. napus hybrids

TORRES CARBONELL, FRANCISCO; URETA, SOLEDAD; PANDOLFO, CLAUDIO; PRESOTTO, ALEJANDRO

ENVIRONMENTAL MONITORING AND ASSESSMENT

SPRINGER

Año: 2020 vol. 192

0167-6369

Herbicide-resistant oilseed rape (Brassica napus) cultivation in our country entails the risk of gene transfer to related wild species. One of these species is the wild turnip (B. rapa), an important weed of winter crops widely distributed in the Pampas region. Despite hybridization risks, Clearfield ® oilseed rape is avail- able in Argentina. In 2008, a B. rapa population, which was sympatric to an imidazolinone-resistant and a con- ventional oilseed rape cultivar, was located on a farm in the main cropping area of the country. Herbicide- resistant individuals were found in the progeny of this population in a herbicide screening test. Therefore, a molecular characterization using cleaved amplified polymorphic sequence (CAPS) and simple sequence repeat (SSR) markers was conducted on these plants to determine their hybrid nature and to establish the origin of the imidazolinone resistance trait. The results of this study, along with information of field records, con- firmed that the resistant plants were first generation interspecific hybrids. Imidazolinone resistance had been effectively transferred from the herbicide-resistant oil- seed rape, even in the particular situation of pollen competition. Oilseed rape resistant cultivars are becom- ing more common in the country. So, considering that seed loss and crop volunteers are common in these species, it is crucial to avoid the dispersion of new resistant weed biotypes as they reduce the effectiveness of chemical control technologies.