Project Details:

Investigation of Genetic Basis of 2,4-D and Dicamba Resistance in Palmer amaranth

Parent Project: Investigation of Genetic Basis of 2,4-D and Dicamba Resistance in Palmer amaranth
Checkoff Organization:Kansas Soybean Commission
Categories:Weed control
Organization Project Code:2166
Project Year:2021
Lead Principal Investigator:Mithila Jugulam (Kansas State University)
Co-Principal Investigators:

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Information and Results

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Project Summary

Prolonged use of herbicides has resulted in development of resistance in weeds to several classes of herbicides including auxinic herbicides, which have been in use for more than 60 years. However, the incidence of auxinic herbicide resistance is relatively low. Resistance to auxinic herbicides in Palmer amaranth biotypes was discovered in Kansas. The primary goal of this research is to determine the inheritance of 2,4-D and dicamba resistance in Palmer amaranth through classical genetic approaches. F1 and F2 progeny will be generated from crosses between homozygous auxinic herbicide-resistant and -susceptible Palmer amaranth parental lines. 2,4-D and dicamba dose-response studies will be conducted. Chi-square analyses of F2 progeny will be performed. The results from the experiments outlined in this proposal will provide for the first-time information about the inheritance of 2,4-D and dicamba resistance in Palmer amaranth. Understanding the genetic basis of herbicide resistance is important to formulate and recommend viable weed management strategies that can delay the evolution of herbicide resistance. If the outcome from the inheritance studies suggests that a single, nuclear, dominant gene confers 2,4-D or dicamba resistance (i.e., a qualitative trait) in Palmer amaranth, then resistance can spread faster in the populations compared to a recessive trait. In such a situation, cultivation can significantly reduce the amount of seed present in the soil seed bank and limit its spread. On the other hand, if the results suggest that the resistance is a multi-genic (i.e., quantitative) trait, weed management practices including 1) crop rotations, 2) use of herbicides with different modes of action, 3) herbicide mixtures, and 4) application of the maximum labeled dose of the herbicide is highly recommended to reduce the spread of resistance.

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Progress of Work

Updated March 4, 2021:

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Final Project Results

Updated August 11, 2021:

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Benefit to Soybean Farmers

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