Pollen- and Seed-Mediated Gene Flow in Kochia (Kochia scoparia). Issue 4 (December 2016)

• Record Type: Journal Article
• Authors: Beckie, Hugh J.; Blackshaw, Robert E.; Hall, Linda M.; Johnson, Eric N.
• Is Part Of: Weed science. Volume 64: Issue 4(2016)
• Page Start: 624
• Page End: 633
• Publication Date: 2016-12
• Subjects: Glyphosate, -- kochia, Kochia scoparia (L.) Schrad., KCHSC; ALS-inhibitor resistance, -- glyphosate resistance, -- herbicide resistance, -- multiple resistance, -- pollen flow; 632.505
• DOI: 10.1614/WS-D-16-00038.1
• Languages: English
• ISSNs: 0043-1745

Abstract

Abstract : Efficient natural dispersal of herbicide-resistance alleles via seed and pollen can markedly accelerate the incidence of herbicide-resistant weed populations across an agroecoregion. Studies were conducted in western Canada in 2014 and 2015 to investigate pollen- and seed-mediated gene flow in kochia. Pollen-mediated gene flow (PMGF) from glyphosate-resistant (GR) to non-GR kochia was quantified in a field trial (hub and spoke design) at Saskatoon, Saskatchewan. Seed-mediated gene flow of acetolactate synthase (ALS) inhibitor-resistant kochia as a function of tumbleweed speed and distance was estimated in cereal stubble fields at Lethbridge, Alberta and Scott, Saskatchewan. Regression analysis indicated that outcrossing from GR to adjacent non-GR kochia ranged from 5.3 to 7.5%, declining exponentially to 0.1 to 0.4% at 96 m distance. However, PMGF was significantly influenced by prevailing wind direction during pollination (maximum of 11 to 17% outcrossing down-wind). Seed dropped by tumbleweeds varied with distance and plant speed, approaching 90% or more (ca. 100, 000 seeds or more) at distances of up to 1, 000 m and plant speeds of up to 300 cm s –1 . This study highlights the efficient proximal (pollen) and distal (seed) gene movement of this important GR weed.