Stability of Herbicide Resistance and GUS Expression in Transgenic Hybrid Poplars (Populus sp.) During Four Years of Field Trials and Vegetative Propagation

We assessed the stability of transgene expression in 79 transgenic lines (i.e., transformation events) of hybrid poplars during several years of field trials. The transgenic lines were comprised of 40 lines of hybrid cottonwoods (P. trichocarpa × P. deltoides) that were grown at three field sites, and 39 lines of hybrid aspens (section Leuce, P. alba × P. tremula) that were grown at a single field site. All the lines were transformed with a binary construct that included two genes that confer tolerance to glyphosate (GOX and CP4), a gene encoding resistance to the antibiotic kanamycin (nptII), and a visible marker gene (GUS). Agrobacterium tumefaciens was used for transformation; callogenesis and organogenesis occurred under kanamycin selection. In addition to repeated applications of herbicide to test stability of transgene expression, for the first time, we challenged ramets of 40 lines that had not previously been tested for herbicide resistance in their fourth season of vegetative growth. We report on the stability of herbicide resistance and GUS expression and evidence for somaclonal variation in growth and leaf morphology.

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The Impact of Different Environmental Conditions during Vegetative Propagation on Growth, Survival, and Biochemical Characteristics in Populus Hybrids in Clonal Field Trial

Forests ◽

10.3390/f12070892 ◽

2021 ◽

Vol 12 (7) ◽

pp. 892

Author(s):

Valda Gudynaitė-Franckevičienė ◽

Alfas Pliūra

Keyword(s):

Climate Change ◽

Phenotypic Plasticity ◽

Environmental Conditions ◽

Vegetative Propagation ◽

Genotypic Variation ◽

Hybrid Poplar ◽

Field Trials ◽

Biochemical Traits ◽

Suburban Areas ◽

Growing Conditions

To have a cleaner environment, good well-being, and improve the health of citizens it is necessary to expand green urban and suburban areas using productive and adapted material of tree species. The quality of urban greenery, resistance to negative climate change factors and pollution, as well as efficiency of short-rotation forestry in suburban areas, depends primarily on the selection of hybrids and clones, suitable for the local environmental conditions. We postulate that ecogenetic response, phenotypic plasticity, and genotypic variation of hybrid poplars (Populus L.) grown in plantations are affected not only by the peculiarities of hybrids and clones, but also by environmental conditions of their vegetative propagation. The aim of the present study was to estimate growth and biochemical responses, the phenotypic plasticity, genotypic variation of adaptive traits, and genetically regulated adaptability of Populus hybrids in field trials which may be predisposed by the simulated contrasting temperature conditions at their vegetative propagation phase. The research was performed with the 20 cultivars and experimental clones of one intraspecific cross and four different interspecific hybrids of poplars propagated under six contrasting temperature regimes in phytotron. The results suggest that certain environmental conditions during vegetative propagation not only have a short-term effect on tree viability and growth, but also can help to adapt to climate change conditions and grow successfully in the long-term. It was found that tree growth and biochemical traits (the chlorophyll A and B, pigments content and the chlorophyll A/B ratio) of hybrid poplar clones grown in field trials, as well as their traits’ genetic parameters, were affected by the rooting-growing conditions during vegetative propagation phase. Hybrids P. balsamifera × P. trichocarpa, and P. trichocarpa × P. trichocarpa have shown the most substantial changes of biochemical traits across vegetative propagation treatments in field trial. Rooting-growing conditions during vegetative propagation had also an impact on coefficients of genotypic variation and heritability in hybrid poplar clones when grown in field trials.

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Weed Control and Selectivity of Pethoxamid Alone and in Mixture as a Delayed Preemergence Application to Rice

Weed Technology ◽

10.1017/wet.2018.57 ◽

2018 ◽

Vol 32 (5) ◽

pp. 537-543

Author(s):

John Godwin ◽

Jason K. Norsworthy ◽

Robert C. Scott

Keyword(s):

Weed Control ◽

Herbicide Resistance ◽

Field Trials ◽

Shoot Density ◽

Red Rice ◽

Weed Species ◽

Viable Option ◽

Long Chain Fatty Acid ◽

Herbicide Resistant ◽

Sites Of Action

AbstractThe evolution of herbicide resistance is making it extremely difficult for US rice producers to use chemical control on weed species such as barnyardgrass and red rice. To combat herbicide resistance, it is imperative that alternative herbicide sites of action (SOAs) be incorporated into rice whenever possible. There are currently no very-long-chain fatty acid–inhibiting herbicides (WSSA Group 15) labeled for use in US rice; however, pethoxamid is one such herbicide currently under development. If appropriate rice tolerance and weed control can be established, pethoxamid would represent a unique herbicide SOA for use in US rice. We conducted field trials near Stuttgart, AR, in 2015 and near Colt and Lonoke, AR, in 2016 to assess selectivity of pethoxamid and weed control alone and in combination with other herbicides as a delayed preemergence (DPRE) application in drill-seeded rice. Pethoxamid was applied at 0, 420, or 560 g ai ha–1 alone and in combination with clomazone, imazethapyr, pendimethalin, and quinclorac. Minimal rice injury occurred with any treatment assessed. A reduction in rice shoot density and plant height compared to the nontreated control followed the use of pethoxamid; however, no decrease in yield resulted. The highest levels of barnyardgrass control followed the use of imazethapyr at 91% and quinclorac at 89% regardless of the presence of pethoxamid near Lonoke; however, pethoxamid applied at both rates in combination with clomazone and quinclorac increased barnyardgrass control compared to clomazone and quinclorac applied alone. Near Colt, barnyardgrass control of 92% and 96% resulted from pethoxamid alone, averaged over the high and low rates. Based on these data, rice can tolerate pethoxamid when applied DPRE, and adequate levels of barnyardgrass control can be achieved at the rates evaluated within a program; hence, pethoxamid appears to be a viable option for use in rice to allow for increased rotation of herbicide SOAs to combat herbicide-resistant and difficult-to-control weeds.

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Management of pigweed (Amaranthus spp.) in grain sorghum with integrated strategies

Weed Technology ◽

10.1017/wet.2019.64 ◽

2019 ◽

Vol 33 (5) ◽

pp. 701-709

Author(s):

Marshall M. Hay ◽

J. Anita Dille ◽

Dallas E. Peterson

Keyword(s):

Herbicide Resistance ◽

Management Strategies ◽

Field Trials ◽

Grain Sorghum ◽

Limited Information ◽

Crop Cultivation ◽

Row Crop ◽

Amaranthus Spp ◽

Narrow Row ◽

Density And Biomass

AbstractPigweed is difficult to manage in grain sorghum because of widespread herbicide resistance, a limited number of registered effective herbicides, and the synchronous emergence of pigweed with grain sorghum in Kansas. The combination of cultural and mechanical control tactics with an herbicide program are commonly recognized as best management strategies; however, limited information is available to adapt these strategies to dryland systems. Our objective for this research was to assess the influence of four components, including a winter wheat cover crop (CC), row-crop cultivation, three row widths, with and without a herbicide program, on pigweed control in a dryland system. Field trials were implemented during 2017 and 2018 at three locations for a total of 6 site-years. The herbicide program component resulted in excellent control (>97%) in all treatments at 3 and 8 weeks after planting (WAP). CC provided approximately 50% reductions in pigweed density and biomass for both timings in half of the site-years; however, mixed results were observed in the remaining site-years, ranging from no attributable difference to a 170% increase in weed density at 8 WAP in 1 site-year. Treatments including row-crop cultivation reduced pigweed biomass and density in most site-years 3 and 8 WAP. An herbicide program is required to achieve pigweed control and should be integrated with row-crop cultivation or narrow row widths to reduce the risk of herbicide resistance. Additional research is required to optimize the use of CC as an integrated pigweed management strategy in dryland grain sorghum.

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Breeding of frosthardy rhododendrons

Agricultural and Food Science ◽

10.23986/afsci.72296 ◽

1988 ◽

Vol 60 (4) ◽

pp. 235-254 ◽

Cited By ~ 1

Author(s):

M. Uosukainen ◽

P. M. A. Tigerstedt

Keyword(s):

Tissue Culture ◽

Plant Breeding ◽

Vegetative Propagation ◽

Minimum Temperature ◽

Genetic Material ◽

Field Trials ◽

Severe Damage ◽

Culture Methods ◽

Maternal Parent ◽

New Cultivars

In 1973 a Rhododendron breeding program was started at the Department of Plant Breeding, University of Helsinki. The program was based on the extremely hardy rhododendron material that had been naturally selected at Arboretum Mustila. The aim was to create new frosthardy cultivars that could tolerate minimum temperatures below —35°C in mid-winter. Rhododendron brachycarpum subsp. tigerstedtii Nitz. was used as the maternal parent in the majority of crosses. Also R. smirnowii and R. catawbiense were used as sources for winter hardiness. Totally 148 different combinations were done between species, species and hybrids and between hybrids. The total number of matings was 496. Over 20 000 seedlings were obtained and a total of 13 752 plants were planted in field trials on eight different test sites between 1975—1979. After two extremely cold winters, 1984/85 and 86/87, about 60 % of the plants died or were severely damaged. R. brachycarpum subsp. tigerstedtii crosses with either R. smirnowii or R. calawbiense gave the best genetic material for better climatic adaptation. The progenies of these crosses survived without any severe damage when minimum temperature was as low as 37°C. Tissue culture methods were developed and used in vegetative propagation of selected ortets. By the end of 1987 six clones have been released as new cultivars for commercial propagation.

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Propagation of Pistacia chinensis by Mound Layering

Journal of Environmental Horticulture ◽

10.24266/0738-2898-13.2.109 ◽

1995 ◽

Vol 13 (2) ◽

pp. 109-112

Author(s):

Diane E. Dunn ◽

Janet C. Cole

Keyword(s):

Vegetative Propagation ◽

Field Trials ◽

Shade Tree ◽

Soil Line

Abstract Chinese pistache (Pistacia chinensis, Bunge.) is a commonly recommended landscape shade tree in the nursery and landscape industry. Currently, Chinese pistache trees are propagated commercially from seed, which results in highly variable branch habit and fall color. Mature Chinese pistache, like other Pistacia have proven difficult to root, graft, or bud successfully. This study was initiated to investigate the potential of mound layering as an alternative vegetative propagation method for producing genetically identical clones of superior mature Chinese pistache trees. Results from a greenhouse pre-trial in which trees were cut at two different heights and at three different morphological stages showed that significantly more shoots were produced when stock plants were cut 5 cm (2 in) above the soil line compared to 1 cm (0.4 in), and when trees completely broke dormancy before cutting. Field trials during two consecutive years evaluated four treatments consisting of 1) wound; 2) 17,500 ppm IBA; 3) wound and 17,500 ppm IBA 4) no wound, no IBA. In 1993, 77% and in 1994, 75%of wounded shoots treated with IBA produced roots.

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Drought Tolerance in Digitaria

The Journal of Agriculture of the University of Puerto Rico ◽

10.46429/jaupr.v55i1.11076 ◽

1969 ◽

Vol 55 (1) ◽

pp. 63-69

Author(s):

A. J. Oakes ◽

W. R. Langford

Keyword(s):

Drought Tolerance ◽

Vegetative Propagation ◽

Field Trials ◽

Wet Season ◽

Digitaria Decumbens ◽

Differential Performance ◽

Survival And Growth

Selected clones of 10 Digitaria species were evaluated for drought tolerance in field trials. Grasses were established by vegetative propagation during the wet season. Observations on survival and growth were made at intervals throughout the 25-month duration of the trial. Approximately one-third of the plants failed to survive, with greatest losses occurring during the period of minimum rainfall. Significant differences in survival among species were found; for example, Digitaria decumbens Stent and Digitaria valida Stent are superior to Digitaria diversinervis (Nees) Stapf and Digitaria swazilandensis Stent. Differential performance of clones within species is demonstrated by two accessions; i.e., USDA P.I. 111110 (Digitaria decumbens Stent) and USDA P.I. 299795 (Digitaria setivalva Stent). Pangola grass and select clones of other Digitaria species may be established by vegetative propagation in rainfall belts of 20 to 30 inches per annum with reasonable assurance of success.

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Subtypes of Attention Deficit Hyperactivity Disorder: Evidence From DSM-IV Field Trials

PsycEXTRA Dataset ◽

10.1037/e328282004-012 ◽

1995 ◽

Author(s):

B. B. Lahey ◽

B. Applegate ◽

K. McBurnett ◽

J. Biederman ◽

L. Greenhill ◽

...

Keyword(s):

Attention Deficit Hyperactivity Disorder ◽

Attention Deficit ◽

Field Trials ◽

Hyperactivity Disorder ◽

Dsm Iv

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Designing and Implementing Randomized Field Trials of Interventions in Schools

PsycEXTRA Dataset ◽

10.1037/e541382012-001 ◽

2007 ◽

Author(s):

George Bohrnstedt ◽

Jeanne Poduska ◽

Mike Garet ◽

Sheppard Kellam ◽

David Myers

Keyword(s):

Field Trials ◽

Randomized Field Trials

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Primary Health Care and the ICD-11

Die Psychiatrie ◽

10.1055/s-0038-1670835 ◽

2013 ◽

Vol 10 (01) ◽

pp. 33-37 ◽

Cited By ~ 2

Author(s):

M. Klinkman ◽

D. Goldberg

Keyword(s):

Health Care ◽

Primary Health Care ◽

Mental Disorders ◽

Medical Care ◽

Special Needs ◽

Field Trials ◽

Primary Medical Care ◽

Dsm 5 ◽

Primary Health ◽

Icd 10

SummaryThis paper describes the necessity of adapting the major classifications of mental disorders exemplified by the ICD-11 and the DSM-5 for the special needs of primary medical care. An earlier version of the classification – the ICD-10-PHC – is described, and the process of adapting it is described in detail. The new 28 item version of the classification is described, and the procedures to be adopted in the Field Trials to be held during 2013 are set out, together with the specific problems these field trials will address.

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