Molecular diagnosis of ALS and ACCase genes and detection of po-tential mutations and responsible for herbicide resistance in Raphanus raphanistrum L. weed from five Iraqi governorates

Abstract

A field experiment was conducted during the winter season of 2022-2023 in one of the agricultural experimental fields at Ibn Al-Bitar Vocational School, located in Al-Hussainiya district of Kerbala governorate. The aim was to evaluate the efficacy of certain chemical herbicides in controlling wild radish weeds and to identify potential mutations in the ALS and ACCase genes responsible for resistance to some chemical herbicides. The experiment was designed according to a randomized complete block design (RCBD) with a split-plot arrangement and three replications. The main plots included five groups of wild radish seeds from five Iraqi governorates (Najaf, Karbala, Babylon, Wasit and Diwaniyah), while the subplots included four chemical herbicides (Navigator, Tatsteler, Mark Zone and Decimate), in addition to the untreated control. Laboratory results showed the presence of missense mutations in the ALS (Synthase acetolactate) gene in the seeds of Karbala, specifically a missense mutation at codon 349. For the seeds from Najaf,  a frame shift mutation was identified, affecting codons 165, 166, 167, 168, 169 and 170. Additionally, a missense mutation was detected in the ACCase (Acetyl-CoA carboxylase) gene in the seeds of Babylon in codon 229. Regarding the field results, the seeds from Wasit weeds excelled by exhibiting the lowest average weed height and chlorophyll content after 60 and 90 days of spraying (60.82 cm and 33.12 SPAD, 80.25 cm and 37.57 SPAD for the two periods, respectively). In contrast, the seeds from Diwaniyah wild radish (Raphanus raphanistrum L.) weeds excelled in terms of control and inhibition percentages after 60 and 90 days of spraying (41.63% and 31.52%, 39.71% and 30.32% for the two periods, respectively). Additionally, Navigator herbicide was notably effective in reducing the height of wild radish weeds, decreasing chlorophyll content, and achieving the highest control and inhibition percentages.