Abstract
Inheritance of glyphosate resistance in a Palmer amaranth biotype from North Carolina was studied. Glyphosate rates for 50% survival of glyphosate-resistant (GR) and glyphosate-susceptible (GS) biotypes were 1288 and 58 g ha−1, respectively. These values for F1 progenies obtained from reciprocal crosses (GR×GSandGS×GRwere 794 and 501 g ha−1, respectively. Dose response of F1 progenies indicated that resistance was not fully dominant over susceptibility. Lack of significant differences between dose responses for reciprocal F1 families suggested that genetic control of glyphosate resistance was governed by nuclear genome. Analysis of F1 backcross (BC1F1) families showed that 10 and 8 BC1F1 families out of 15 fitted monogenic inheritance at 2000 and 3000 g ha−1glyphosate, respectively. These results indicate that inheritance of glyphosate resistance in this biotype is incompletely dominant, nuclear inherited, and might not be consistent with a single gene mechanism of inheritance. Relative 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) copy number varied from 22 to 63 across 10 individuals from resistant biotype. This suggested that variableEPSPScopy number in the parents might be influential in determining if inheritance of glyphosate resistance is monogenic or polygenic in this biotype.
Highlights
Glyphosate has become the world’s most widely used herbicide since its commercialization in 1974, because it is effective, economical, and comparatively safe to the environment [1, 2]
Inheritance of glyphosate resistance as an incompletely dominant trait controlled by nuclear genes has been reported in other weed species [17, 27,28,29]
Values for percent survival of both sets of F1 families at a given glyphosate dose were not significantly different from each other (Figure 1 and Table 1), indicating that genetic control of glyphosate resistance is governed by the nuclear genome and that there is no maternal or cytoplasmic inheritance involved
Summary
Glyphosate has become the world’s most widely used herbicide since its commercialization in 1974, because it is effective, economical, and comparatively safe to the environment [1, 2]. Glyphosate is used to control a wide array of weed species including both grasses and broadleaf weeds [3, 4]. When glyphosate-resistant (GR) crops {including canola (Brassica napus L.), corn (Zea mays L.), cotton (Gossypium hirsutum L.), and soybean (Glycine max (L.) Merr.)} were commercialized beginning from 1996 to 1998, glyphosate revolutionized production of these crops by enabling growers to use this herbicide for weed control in standing crops [1]. Glyphosate resistance has been confirmed in 13 weed species in the United States, including Palmer amaranth The extent of GR Palmer amaranth biotypes has been well documented [8,9,10], information is limited about the genetic control of resistance in this species. Among other factors, is an important component affecting the evolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
