GENETICS OF GROUP 14 HERBICIDE TOLERANCE IN LENTIL
Date
2019-06-12
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Degree Level
Doctoral
Abstract
Extremely weak competition with weeds and limited herbicide options dictate the need to explore new avenues in weed control for lentil. Sulfentrazone and fluthiacet methyl are two herbicides of group 14 which have not previously been used in lentil production.
Tolerance to these two products was investigated through a set of field trials in combination with electrolyte leakage assays. The result of field trials showed that sulfentrazone has a more significant effect on the yield. The electrolyte leakage assay results confirm existence of variable levels of herbicide tolerance.
A set of 110 diverse lentil genotypes was then used in multi-environment trials to test the association between genetic markers and traits related to damage due to exposure to fluthiacet methyl. Several groups of genes were detected; among the candidate genes were cytochrome P450s, glutathione-S-transferases, some stress-related genes and50 genes involve in plant growth and development. This suggests that a non-target site resistance mechanism in combination with plant regrowth is the main cause for the observed differences in tolerance. A follow-up study on the importance of cytochrome P450s and glutathione-S-transferase demonstrated that cytochrome P450s play an important role in tolerance to both herbicides, while glutathione-S-transferase plays more sporadic role.
As a target site of sulfentrazone and fluthiacet methyl, protoporphyrinogen oxidase genes were sequenced across multiple lentil genotypes. Several single nucleotide polymorphisms (SNPs) were detected to cause amino acid substitution in target enzymes. Based on single marker analysis, one SNP was found to play a role in tolerance to fluthiacet methyl. Finally, mutation breeding was used to generate material with a higher level of tolerance to both herbicides. After initial screening, several mutant lines were selected for further validation. In the case of sulfentrazone no lines had higher levels of tolerance, but for fluthiacet methyl, two mutant lines showed promise.
The potential for use of sulfentrazone and fluthiacet methyl in lentil production exists, but it requires extensive breeding effort to produce genetic material with herbicide resistance. The knowledge collected in this research creates the blueprint for future work and development of herbicide-resistant lentil varieties.
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Keywords
lentil, Lens culinaris, protoporphyrinogen oxidase, herbicide, PPO inhibitors, sulfentrazone, fluthiacet methyl, electrolyte leakage assay, GWAS, mutation breeding
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Plant Sciences
Program
Plant Sciences