Genetic basis of dinitroaniline herbicide resistance in a highly resistant biotype of goosegrass (Eleusine indica)

The inheritance of dinitroaniline herbicide resistance was investigated based on the dinitroaniline response phenotype of F-1 plants and segregation analysis in F-2 and F-3 progenies, Reciprocal crosses were made between two susceptible (S) biotypes and two resistant (R) biotypes, Seven F-1 hybrids were identified by isoenzyme analysis, and F-2 and F-3 populations were derived from these F-1 plants by selfing, The dinitroaniline response phenotype of F-1 plants and F-2 and F-3 seedlings was determined using a root growth bioassay, F-1 plants were phenotypically susceptible (i,e,, identical to their S parental plants), indicating that resistance is recessive to susceptibility, Nonparental phenotypes were not observed, and data from reciprocal crosses gave no indication of maternal or paternal inheritance, F-2 seedlings were classified as either S or R phenotype, The observed segregation ratio of S to R seedlings fit only a 3:1 (S:R) ratio, Segregation data indicated the dinitroaniline herbicide-response phenotype is inherited as a single nuclear gene, and it identified two alleles (i,e,, Drp(s) and Drp(r)) at this single locus, The 3:1 segregation ratio was confirmed by analysis of F-3 progenies, Taken together, results from F-1, F-2 and F-3 plants were consistent with dinitroaniline herbicide resistance being inherited as a single, recessive nuclear gene.