Inheritance of Provisia rice resistance to quizalofop-p-ethyl under laboratory and greenhouse environments

The BASF Corporation recently developed Provisia rice that is resistant to the ACCase inhibitor quizalofop-p-ethyl (QPE) for control of grassy weeds and that is complementary to the existing Clearfield((R)) technology. The objective of this research was to determine the inheritance of resistance to QPE in different populations of rice evaluated under laboratory and greenhouse conditions. Five QPE-resistant lines and 13 susceptible U.S. varieties and breeding lines were used to develop 16 F-1 populations that showed dominant gene control for QPE resistance in the greenhouse. Germinating seeds and young seedlings from 16 F-2 and 12 BC1F1 populations, along with corresponding susceptible and resistant parents, were exposed to minimum lethal concentrations of QPE. The results indicated that resistance to QPE under the two environments was governed by a single dominant Mendelian gene with no observable maternal effects. Allele-specific SNP markers for QPE resistance were developed that also followed Mendelian segregation in four F-2 and six BC1F1 populations. Results from this study have direct implications for breeding strategies of inbred and hybrids varieties resistant to QPE in the laboratory and greenhouse and for effective stewardship of the Provisia technology.