Evaluation of wheat cultivars for seedling tolerance to atrazine

Abstract

Abstract Winter wheat ( Triticum aestivum L.) is sometimes planted after maize ( Zea mays L.) or sorghum ( Sorghum bicolor (L.) Moench) has been harvested. If the herbicide atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)- s -triazine] was used on the maize or sorghum crop, the residue can reduce the stand of wheat. The objective of this research was to develop a screening technique to differentiate the seedling response of wheat cultivars to atrazine. Wheat was grown in the greenhouse in flats containing a Captina silt loam soil (fine-silty, mixed, mesic typic Fragiudult) treated with atrazine rates ranging from 0 to 1.0 mg kg −1 . Survival ratings made after 4 weeks indicated that atrazine rates used to differentiate among genotypes should be less than 0.4 mg kg −1 . To determine the proper concentration to use for screening cultivars, another experiment was conducted using eight atrazine rates ranging from 0 to 0.4 mg kg −1 . Based upon results from this study, 120 cultivars and lines were screened at 0.25 mg kg −1 atrazine for 4 weeks. ‘TexRed’, ‘Maverick’, AR 67-3-19, ‘McNair 1813’, and ‘Potomac’ had the highest survival ratings among genotypes. This screening procedure is an effective preliminary method to identify wheat genotypes with seedling resistance to atrazine.