Genomic characterisation and dissection of the onset of resistance to acetyl CoA carboxylase-inhibiting herbicides in a large collection of Digitaria insularis from Brazil

An in-depth genotypic characterisation of a diverse collection of Digitaria insularis was undertaken to explore the neutral genetic variation across the natural expansion range of this weed species in Brazil. With the exception of Minas Gerais, populations from all other states showed high estimates of expected heterozygosity (HE > 0.60) and genetic diversity. There was a lack of population structure based on geographic origin and a low population differentiation between populations across the landscape as evidenced by an average Fst value of 0.02. On combining haloxyfop [acetyl CoA carboxylase (ACCase)-inhibiting herbicide] efficacy data with neutral genetic variation, we found evidence of the presence of two scenarios of resistance evolution in this weed species. Whilst populations originating from north-eastern region demonstrated an active role of gene flow, populations from the mid-western region displayed multiple, independent resistance evolution as the major evolutionary mech..., Plant material
A total of 205 D. insularis weed populations were used in the study. The populations were collected from the most relevant soybean- (and corn) growing regions across Brazil inhabiting crop fields and crop margins in the southern, mid-western, south-eastern, and north-eastern regions. Briefly, these 205 populations originated from seven states including Mato Grosso (77), Mato Grosso do Sul (10), Minas Gerais (19), Bahia (24), Goiás (20), Paraná (PR) and Rio Grande do Sul (18). The detailed information on the geographic origin and geographic coordinates are provided in the supplementary table (Table S1). Some collection sites (1/5th of the collection) had a history of multiple herbicide treatments on the crop including glyphosate, ACCase inhibitors such as haloxyfop or clethodim alone, or in mixtures and/or ALS inhibitors (Table S1). The populations were collected in 2020 and 2021 and were investigated for their sensitivity to ACCase inhibitors haloxyfop and clethodim at mu..., , # Genomic characterization and GWAS of Digitaria insularis

An in-depth genotypic characterisation of a diverse collection of Digitaria insularis was undertaken to explore the neutral genetic variation across the natural expansion range of this weed species in Brazil. With the exception of Minas Gerais, populations from all other states showed high estimates of expected heterozygosity (HE > 0.60) and genetic diversity. There was a lack of population structure based on geographic origin and a low population differentiation between populations across the landscape as evidenced by average Fst value of 0.02. On combining haloxyfop [acetyl CoA carboxylase (ACCase)-inhibiting herbicide] efficacy data with neutral genetic variation, we found evidence of presence of two scenarios of resistance evolution in this weed species. Whilst populations originating from north-eastern region demonstrated an active role of gene flow, populations from the mid-western region displayed multiple, independ...