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ARS Home » Midwest Area » Madison, Wisconsin » Vegetable Crops Research » Research » Research Project #434431

Research Project: Pollinators and Gene Flow

Location: Vegetable Crops Research

Project Number: 5090-21000-068-00-D
Project Type: In-House Appropriated

Start Date: Mar 26, 2018
End Date: Mar 25, 2023

Objective:
Objective 1: Identify pollinator behaviors, pollinator management strategies, and crop production strategies that together mitigate unintended gene flow. Sub-objective 1.1: Pollinator behavior and plant reproductive strategies affect gene flow risk. Sub-objective 1.2: Visual and Olfactory cues that attract pollinators can guide the development of pollinator or crop management strategies that reduce gene flow and increase yield. Objective 2: Determine the impacts of cultivated carrot genes on the genomic landscape of wild carrot.

Approach:
Objective 1. This objective is divided into two sub-objectives, each with three hypotheses to be tested. Sub-Objective 1.1. We will use a combination of field and greenhouse experiments to test the hypotheses within this subobjective. For example, the rules bees use when moving between patches or fields will be tested using patches of distinct sizes and isolation distances and measuring the number of transitions made by bees from a center glyphosate-resistant patch to the different conventional patches. The number of gene flow events in the different conventional patches, identified by the presence of glyphosate-resistant seeds, will also be used to test the decision making process of bumble bees. Greenhouse experiments will examine the pattern of seed deposition on flowers visited in succession by three bee species, honey bees, leafcutting bees and bumble bees. We will use glyphosate-resistant pollen donor and conventional pollen recipients and examine the number and proportion of glyphosate-resistant seeds on flowers visited in succession to determine the seed curve for each bee species. Sub-Objective 1.2. To determine the preference of each of three bee species to visual and/or olfactory cues, we will perform greenhouse experiments and quantify approaches and landings to different visual and/or olfactory cues. To identify a blend derived from nest cells that attract leafcutting bees, we will capture and identify the chemicals present in the bee cell using Gas Chromatography-Mass Spectrometry (GC-MS); determine whether there is a behavioral response and then use couple gas chromatography – electroantennographic detection (GC-EAD) to identify physiological responses. Finally, the electrophysiologically active constituents will be tested using a behavioral assay. Objective 2. We will use genotyping by sequencing on both cultivated carrots used in a breeding program and wild carrots in close proximity to the breeding area and far away to detect the presence of cultivated carrot genes in wild carrot populations. The presence of cultivated genes in wild populations represents introgression. We will determine the extent of introgression of cultivar genes in wild carrot populations.