Impact of transgene genome location on gene migration from herbicide-resistant wheat (Triticum aestivumL.) to jointed goatgrass (Aegilops cylindricaHost)

Jointed goatgrass is a major weed in the wheat-producing areas of the western U.S. It shares the D genome with wheat, and interspecific hybrids between the two species occur in the field. The objective of this research was to determine if wheat X jointed goatgrass hybrids could serve to transfer genes from wheat to jointed goatgrass. A backcrossing program was initiated in the greenhouse between wheat X jointed goatgrass hybrids and either jointed goatgrass or wheat to determine the potential for seed set and the restoration of self-fertility. Seed was set by backcrossing with either species as the recurrent parent. Female fertility increased from 2% in the hybrid to 37% in the BC2 plants with jointed goatgrass as the recurrent parent. Partial self-fertility was restored in the second backcross (BC2) generation using jointed goatgrass as the recurrent parent. This indicates that genes could be transferred between wheat and jointed goatgrass after only two backcrosses. The number of bivalents observed in the plants during meiosis appeared to be key to increasing female fertility and self-fertility. Based on the results of this study, it is possible for genes to move from wheat to jointed goatgrass. Any release of a herbicide-resistant wheat should be accompanied by a management plan that would minimize the potential for gene movement between these species.

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Production of herbicide-resistant jointed goatgrass (Aegilops cylindrica) × wheat (Triticum aestivum) hybrids in the field by natural hybridization

Weed Science ◽

10.1017/s004317450008961x ◽

1998 ◽

Vol 46 (6) ◽

pp. 632-634 ◽

Cited By ~ 64

Author(s):

Steven S. Seefeldt ◽

Robert Zemetra ◽

Frank L. Young ◽

Stephen S. Jones

Keyword(s):

Management Strategies ◽

Natural Hybridization ◽

Efficacy Study ◽

Wheat Seed ◽

Aegilops Cylindrica ◽

Herbicide Resistant ◽

Jointed Goatgrass ◽

Hybrid Plants ◽

Resistance Trait ◽

Viable Seeds

Imazamox-resistant hybrids resulted from a cross between jointed goatgrass and an imazamox-resistant wheat (cv. FS-4 IR wheat). Two imazamox-resistant hybrids were discovered in a research plot where FS-4 IR wheat seed had been replanted from the harvest of an imazamox efficacy study conducted the year before at a different location. These hybrid plants survived imazamox applied at 0.053 and 0.069 kg ai ha−1in the field and produced seven viable seeds (BC1). This seed germinated, and chromosomes were counted from the roots (2N number ranged from 39 to 54). In the greenhouse, six of the seven plants survived an application of 0.072 kg ai ha−1imazamox, which confirmed that the resistance trait had been passed to these progeny. A large amount of phenotypic variation was observed in the mature BC1plants. A genetic description of the movement of the resistant gene is proposed based on the case of the gene being located on the D and the A or B genomes. Management strategies to reduce the occurrence of herbicide-resistant hybrids are presented.

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Interspecific Hybridization: Potential for Movement of Herbicide Resistance from Wheat to Jointed Goatgrass (Aegilops cylindrica)

Weed Technology ◽

10.1614/wt-04-217r.1 ◽

2005 ◽

Vol 19 (3) ◽

pp. 674-682 ◽

Cited By ~ 28

Author(s):

Bradley D. Hanson ◽

Carol A. Mallory-Smith ◽

William J. Price ◽

Bahman Shafii ◽

Donald C. Thill ◽

...

Keyword(s):

Pacific Northwest ◽

Great Plains ◽

Herbicide Resistance ◽

Field Experiments ◽

Introgressive Hybridization ◽

Acetolactate Synthase ◽

The United States ◽

Aegilops Cylindrica ◽

Herbicide Resistant ◽

Jointed Goatgrass

The transfer of herbicide resistance genes from crops to related species is one of the greatest risks of growing herbicide-resistant crops. The recent introductions of imidazolinone-resistant wheat in the Great Plains and Pacific Northwest regions of the United States and research on transgenic glyphosate-resistant wheat have raised concerns about the transfer of herbicide resistance from wheat to jointed goatgrass via introgressive hybridization. Field experiments were conducted from 2000 to 2003 at three locations in Washington and Idaho to determine the frequency and distance that imidazolinone-resistant wheat can pollinate jointed goatgrass and produce resistant F1hybrids. Each experiment was designed as a Nelder wheel with 16 equally spaced rays extending away from a central pollen source of ‘Fidel-FS4’ imidazolinone-resistant wheat. Each ray was 46 m long and contained three rows of jointed goatgrass. Spikelets were collected at maturity at 1.8-m intervals along each ray and subjected to an imazamox screening test. The majority of all jointed goatgrass seeds tested were not resistant to imazamox; however, 5 and 15 resistant hybrids were found at the Pullman, WA, and Lewiston, ID, locations, respectively. The resistant plants were identified at a maximum distance of 40.2 m from the pollen source. The overall frequency of imazamox-resistant hybrids was similar to the predicted frequency of naturally occurring acetolactate synthase resistance in weeds; however, traits with a lower frequency of spontaneous mutations may have a relatively greater risk for gene escape via introgressive hybridization.

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Herbicide-Resistant Grass Weed Development in Imidazolinone-Resistant Wheat: Weed Biology and Herbicide Rotation

Weed Technology ◽

10.1614/wt-03-167r ◽

2004 ◽

Vol 18 (3) ◽

pp. 860-868 ◽

Cited By ~ 7

Author(s):

Curtis R. Rainbolt ◽

Donald C. Thill ◽

Joseph P. Yenish ◽

Daniel A. Ball

Keyword(s):

Winter Wheat ◽

Seed Bank ◽

Cropping Systems ◽

Soil Seed Bank ◽

Wild Oat ◽

Downy Brome ◽

Weed Biology ◽

Soil Seed Banks ◽

Herbicide Resistant ◽

Jointed Goatgrass

A general life cycle model was modified to demonstrate how agronomic practices and weed biology factors affect the rate of appearance of herbicide-resistant downy brome, jointed goatgrass, and wild oat in Pacific Northwest wheat cropping systems. The model suggests herbicide rotation strategies for cropping systems that include imidazolinone-resistant wheat as a weed management tool. Simulation of continuous annual imidazolinone-resistant winter wheat and imazamox herbicide use resulted in the resistant soil seed banks of downy brome, jointed goatgrass, and wild oat surpassing their susceptible soil seed banks in 5, 7, and 10 yr, respectively. Reducing the initial seed bank density of downy brome before beginning a rotation that includes imidazolinone-resistant winter wheat reduces the likelihood of selecting for herbicide-resistant biotypes. The best simulated management option for reducing the total jointed goatgrass soil seed bank in low-precipitation areas is an imidazolinone-resistant winter wheat–fallow rotation. Rotations that include winter and spring crops and rotations that include non–group 2 herbicides minimize herbicide resistance selection pressure and reduce the wild oat soil seed bank.

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Selective Control of Jointed Goatgrass (Aegilops cylindrica) with Imazamox in Herbicide-Resistant Wheat

Weed Technology ◽

10.1017/s0890037x00044948 ◽

1999 ◽

Vol 13 (1) ◽

pp. 77-82 ◽

Cited By ~ 33

Author(s):

Daniel A. Ball ◽

Frank L. Young ◽

Alex G. Ogg

Keyword(s):

Winter Wheat ◽

Pacific Northwest ◽

Wheat Cultivar ◽

Wheat Yield ◽

Wheat Grain ◽

Winter Wheat Cultivar ◽

Aegilops Cylindrica ◽

Herbicide Resistant ◽

Jointed Goatgrass ◽

Selective Control

Jointed goatgrass (Aegilops cylindrica) is a serious problem for winter wheat producers throughout the western U.S. Interference from this weed can severely reduce grain yield and contaminate harvested grain, resulting in dockage losses. There are currently no selective herbicides registered for controlling jointed goatgrass in wheat. Imazamox, an imidazolinone herbicide, was applied to an imidazolinone herbicide-resistant (IMI) wheat mutant of the winter wheat cultivar ‘Fidel.’ Jointed goatgrass control from spring postemergence application of imazamox ranged from 61 to 97% when applied at 36 g/ha. Negligible crop injury from imazamox treatment was observed at 36 g/ha at several locations under dryland environments in the U.S. Pacific Northwest. Wheat yield was increased 19 to 41% by imazamox treatment in three of four experiments. Percent dockage resulting from jointed goatgrass spikelet contamination of harvested wheat grain was eliminated by imazamox treatment. Introduction of the IMI trait into commercial wheat cultivars could provide an effective method for selective control of jointed goatgrass in winter wheat.

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Winter wheat competition against jointed goatgrass (Aegilops cylindrica) as influenced by wheat plant height, seeding rate, and seed size

Weed Science ◽

10.1614/ws-04-006r ◽

2004 ◽

Vol 52 (6) ◽

pp. 996-1001 ◽

Cited By ~ 23

Author(s):

Joseph P. Yenish ◽

Frank L. Young

Keyword(s):

Winter Wheat ◽

Plant Height ◽

Seed Size ◽

Wheat Variety ◽

Wheat Yield ◽

Cultural Control ◽

Wheat Seed ◽

Seeding Rate ◽

Herbicide Resistant ◽

Jointed Goatgrass

Jointed goatgrass is a troublesome weed in winter wheat with selective control only possible with a herbicide-resistant crop. Even with herbicide-resistant wheat, cultural control is still an important part of jointed goatgrass management. A study was conducted in 1998 and 2000 to determine whether using larger sized seed of a tall wheat variety at an increased seeding rate would reduce the effect of jointed goatgrass on winter wheat. Wheat seed size, seeding rate, and variety height had no effect on jointed goatgrass plant density. Tall (∼130 cm) wheat reduced mature jointed goatgrass biomass 46 and 16% compared with short (∼100 cm) wheat in years 1 and 2 of the experiment, respectively. Spikelet biomass was also reduced approximately 70 and 30% in the same respective years. One thousand–spikelet weight of jointed goatgrass was reduced 37 and 7% in years 1 and 2, respectively, when grown in competition with taller compared with shorter wheat. Moreover, dockage was 80 and 30% less in years 1 and 2, respectively, when grown in competition with taller than shorter wheat. Mature jointed goatgrass height was similar regardless of the competitive wheat height. However, jointed goatgrass was as much as 18% taller than the short wheat and 15% shorter than the tall wheat. Seeding rate had the most consistent effect on wheat yield. Wheat seed yield was about 10% greater with 60 than 40 seed m−1of row when competing with jointed goatgrass. Results of this study indicate that growers could use a tall winter wheat variety to improve crop competition against jointed goatgrass. Results also indicate that plant breeders should consider plant height because herbicide-resistant varieties are developed for the integrated management of jointed goatgrass.

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Cloning of New Herbicide Resistant Gene in Soil Metagenomics and Generation of Transgenic Rice Plants

ACTA AGRONOMICA SINICA ◽

10.3724/sp.j.1006.2014.01190 ◽

2014 ◽

Vol 40 (7) ◽

pp. 1190

Author(s):

Yun-Peng WANG ◽

Jing-Yong MA ◽

Rui MA ◽

Jian MA ◽

Wen-Guo LIU

Keyword(s):

Transgenic Rice ◽

Herbicide Resistant ◽

Rice Plants ◽

Resistant Gene ◽

Transgenic Rice Plants ◽

Soil Metagenomics

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Monarch butterfly and milkweed declines substantially predate the use of genetically modified crops

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1811437116 ◽

2019 ◽

Vol 116 (8) ◽

pp. 3006-3011 ◽

Cited By ~ 20

Author(s):

J. H. Boyle ◽

H. J. Dalgleish ◽

J. R. Puzey

Keyword(s):

Genetically Modified ◽

Danaus Plexippus ◽

Genetically Modified Crops ◽

Monarch Butterfly ◽

The United States ◽

Gm Crops ◽

Herbicide Resistant ◽

The Past ◽

Scientific Attention ◽

Herbicide Use

Monarch butterfly (Danaus plexippus) decline over the past 25 years has received considerable public and scientific attention, in large part because its decline, and that of its milkweed (Asclepias spp.) host plant, have been linked to genetically modified (GM) crops and associated herbicide use. Here, we use museum and herbaria specimens to extend our knowledge of the dynamics of both monarchs and milkweeds in the United States to more than a century, from 1900 to 2016. We show that both monarchs and milkweeds increased during the early 20th century and that recent declines are actually part of a much longer-term decline in both monarchs and milkweed beginning around 1950. Herbicide-resistant crops, therefore, are clearly not the only culprit and, likely, not even the primary culprit: Not only did monarch and milkweed declines begin decades before GM crops were introduced, but other variables, particularly a decline in the number of farms, predict common milkweed trends more strongly over the period studied here.

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Establishing white clover (Trifolium repens) as a living mulch: weed control and herbicide tolerance

Weed Technology ◽

10.1017/wet.2021.45 ◽

2021 ◽

pp. 1-28

Author(s):

Nicholas T. Basinger ◽

Nicholas S. Hill

Keyword(s):

Weed Control ◽

White Clover ◽

Cover Crops ◽

Herbicide Tolerance ◽

Single Application ◽

Weed Species ◽

Living Mulch ◽

Herbicide Resistant ◽

Research And Education ◽

Weed Emergence

Abstract With the increasing focus on herbicide-resistant weeds and the lack of introduction of new modes of action, many producers have turned to annual cover crops as a tool for reducing weed populations. Recent studies have suggested that perennial cover crops such as white clover could be used as living mulch. However, white clover is slow to establish and is susceptible to competition from winter weeds. Therefore, the objective of this study was to determine clover tolerance and weed control in established stands of white clover to several herbicides. Studies were conducted in the fall and winter of 2018 to 2019 and 2019 to 2020 at the J. Phil Campbell Research and Education Center in Watkinsville, GA, and the Southeast Georgia Research and Education Center in Midville, GA. POST applications of imazethapyr, bentazon, or flumetsulam at low and high rates, or in combination with 2,4-D and 2,4-DB, were applied when clover reached 2 to 3 trifoliate stage. Six weeks after the initial POST application, a sequential application of bentazon and flumetsulam individually, and combinations of 2,4-D, 2,4-DB, and flumetsulam were applied over designated plots. Clover biomass was similar across all treatments except where it was reduced by sequential applications of 2,4-D + 2,4-DB + flumetsulam in the 2019 to 2020 season indicating that most treatments were safe for use on establishing living mulch clover. A single application of flumetsulam at the low rate or a single application of 2,4-D + 2,4-DB provided the greatest control of all weed species while minimizing clover injury when compared to the non-treated check. These herbicide options allow for control of problematic winter weeds during clover establishment, maximizing clover biomass and limiting canopy gaps that would allow for summer weed emergence.

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Effects of cereal rye seeding rate on waterhemp (Amaranthus tuberculatus) emergence and soybean growth and yield

Weed Technology ◽

10.1017/wet.2021.28 ◽

2021 ◽

pp. 1-25

Author(s):

Mandy Bish ◽

Brian Dintelmann ◽

Eric Oseland ◽

Jacob Vaughn ◽

Kevin Bradley

Keyword(s):

Crop Production ◽

Production Systems ◽

Soil Seed Bank ◽

Linear Regression Analysis ◽

Growth And Yield ◽

Seeding Rate ◽

Early Season ◽

Cereal Rye ◽

Herbicide Resistant ◽

Growing Seasons

Abstract The evolution of herbicide-resistant weeds has resulted in the necessity to integrate non-chemical control methods with chemicals for effective management in crop production systems. In soybean, control of the pigweed species, particularly herbicide-resistant waterhemp and Palmer amaranth, have become predominant concerns. Cereal rye planted as a winter cover crop can effectively suppress early-season weed emergence in soybean, including waterhemp, when planted at a rate of 123 kg ha−1. The objectives of this study were to determine the effects of different cereal rye seeding rates (0, 34, 56, 79, 110, and 123 kg ha−1) on early-season waterhemp suppression and soybean growth and yield. Soybean was planted into fall-seeded cereal rye, which was terminated within four days of soybean planting. The experiment was conducted over the 2018, 2019, and 2020 growing seasons in Columbia, Missouri. Effects of cereal rye on early-season waterhemp suppression varied by year and were most consistent at 56 kg ha−1 or higher seeding rates. Linear regression analysis of cereal rye biomass, height, or stand at soybean planting showed inverse relationships with waterhemp emergence. No adverse effects to soybean growth or yield were observed at any of the cereal rye seeding rates relative to plots that lacked cereal rye cover. Result differences among the years suggest that the successfulness of cereal rye on suppression of early-season waterhemp emergence is likely influenced by the amount of waterhemp seed present in the soil seed bank.

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