scholarly journals Field Evaluation of Herbicide-resistant Transgenic Broccoli

HortScience ◽  
2000 ◽  
Vol 35 (5) ◽  
pp. 930-932 ◽  
Author(s):  
D. Waterer ◽  
S. Lee ◽  
G. Scoles ◽  
W. Keller

This study examined the field performance and herbicide resistance of lines of broccoli (Brassica oleracea Italica Group) generated from plants transformed for resistance to the herbicide glufosinate by Agrobacterium-mediated gene transfer. Seedling vigor and vegetative growth characteristics of the first recombinant generation (R1) produced by selfing the transformed lines were comparable to those of the F1 parent (cv. Cruiser) and an equivalent nontransformed F2 line. In hand-weeded trials, marketable yields of the R1-transformed lines were comparable to the parental line or the corresponding nontransformed F2 line. A single application of the recommended rate of the nonselective herbicide glufosinate slowed the growth and reduced yields of nontransformed broccoli, but had little effect on head quality or yields of most transformed lines. Inheritance of herbicide resistance in the R1 progeny of the R0 transgenic plants followed standard Mendelian ratios for a completely dominant trait controlled by a single gene. The results confirm the potential for improvement of broccoli through the incorporation of herbicide resistance by gene transfer technology. Chemical name used: 2-amino-(4-hydroxymethylphosphinyl)butanoic acid (glufosinate, phosphinothricine).

2021 ◽  
pp. 1-28
Author(s):  
Nicholas T. Basinger ◽  
Nicholas S. Hill

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.


Weed Science ◽  
2021 ◽  
pp. 1-25
Author(s):  
Qian Yang ◽  
Xia Yang ◽  
Zichang Zhang ◽  
Jieping Wang ◽  
Weiguo Fu ◽  
...  

Abstract Barnyardgrass (Echinochloa crus-galli) is a noxious grass weed which infests rice fields and causes huge crop yield losses. In this study, we collected twelve E. crus-galli populations from rice fields of Ningxia province in China and investigated the resistance levels to acetolactate synthase (ALS) inhibitor penoxsulam and acetyl-CoA carboxylase (ACCase) inhibitor cyhalofop-butyl. The results showed that eight populations exhibited resistance to penoxsulam and four populations evolved resistance to cyhalofop-butyl. Moreover, all of the four cyhalofop-butyl-resistant populations (NX3, NX4, NX6 and NX7) displayed multiple-herbicide-resistance (MHR) to both penoxsulam and cyhalofop-butyl. The alternative herbicides bispyribac-sodium, metamifop and fenoxaprop-P-ethyl cannot effectively control the MHR plants. To characterize the molecular mechanisms of resistance, we amplified and sequenced the target-site encoding genes in resistant and susceptible populations. Partial sequences of three ALS genes and six ACCase genes were examined. A Trp-574-Leu mutation was detected in EcALS1 and EcALS3 in two high-level (65.84- and 59.30-fold) penoxsulam-resistant populations NX2 and NX10, respectively. In addition, one copy (EcACC4) of ACCase genes encodes a truncated aberrant protein due to a frameshift mutation in E. crus-galli populations. None of amino acid substitutions that are known to confer herbicide resistance were detected in ALS and ACCase genes of MHR populations. Our study reveals the widespread of multiple-herbicide resistant E. crus-galli populations at Ningxia province of China that exhibit resistance to several ALS and ACCase inhibitors. Non-target-site based mechanisms are likely to be involved in E. crus-galli resistance to the herbicides, at least in four MHR populations.


Author(s):  
Lina Kloub ◽  
Sean Gosselin ◽  
Matthew Fullmer ◽  
Joerg Graf ◽  
J Peter Gogarten ◽  
...  

Abstract Horizontal gene transfer (HGT) is central to prokaryotic evolution. However, little is known about the “scale” of individual HGT events. In this work, we introduce the first computational framework to help answer the following fundamental question: How often does more than one gene get horizontally transferred in a single HGT event? Our method, called HoMer, uses phylogenetic reconciliation to infer single-gene HGT events across a given set of species/strains, employs several techniques to account for inference error and uncertainty, combines that information with gene order information from extant genomes, and uses statistical analysis to identify candidate horizontal multi-gene transfers (HMGTs) in both extant and ancestral species/strains. HoMer is highly scalable and can be easily used to infer HMGTs across hundreds of genomes. We apply HoMer to a genome-scale dataset of over 22000 gene families from 103 Aeromonas genomes and identify a large number of plausible HMGTs of various scales at both small and large phylogenetic distances. Analysis of these HMGTs reveals interesting relationships between gene function, phylogenetic distance, and frequency of multi-gene transfer. Among other insights, we find that (i) the observed relative frequency of HMGT increases as divergence between genomes increases, (ii) HMGTs often have conserved gene functions, and (iii) rare genes are frequently acquired through HMGT. We also analyze in detail HMGTs involving the zonula occludens toxin and type III secretion systems. By enabling the systematic inference of HMGTs on a large scale, HoMer will facilitate a more accurate and more complete understanding of HGT and microbial evolution.


1990 ◽  
Vol 30 (4) ◽  
pp. 569 ◽  
Author(s):  
RA Drew ◽  
MK Smith

Field performance is described for tissue cultured plants and conventional propagules of planting material of banana cultivar 'New Guinea Cavendish' (Musa sp., AAA group, Cavendish subgroup). Tissuecultured plants were produced by either regeneration of plants from callus culture or by micropropagation of plants following the release of dormant buds at the leaf axils of explants. The conventional material consisted of suckers and 'bits' (lateral buds and associated corm material). Tissue-cultured plants established more quickly, were taller, and had a shorter time to bunch emergence and harvest of plant crop than conventional planting material. They had significantly (P<0.05) higher yields in terms of bunch weight, which was a function of greater numbers of fingers and hands. These advantages did not extend to the ratoon crop. Sucker production on tissue-cultured plants was significantly (P<0.01) higher up to 8 months after planting, equal to conventional material from 8 months to harvest, and then significantly lower. Twenty-two per cent of the plants derived from callus were off-types compared with 3% in the line produced by axillary bud proliferation. No off-types were observed in conventional planting material.


2013 ◽  
Vol 153 (2) ◽  
pp. 195-204 ◽  
Author(s):  
F. FADHEL ◽  
A. J. JELLINGS ◽  
S. KENNEDY ◽  
M. P. FULLER

SUMMARYBreeding trials for swede (Brassica napus var. napobrassica) in 2000–2010 showed that 0·85 of the incidence of brown heart (BH) in the trials was associated with genotypes that are progeny of Ag31, Or13 and Me77c. In order to investigate this and the effect of treatment with boron (B), established varieties and improved parent lines carrying male sterility (ms), and their F1 hybrids (test hybrids), were grown in a field trial in the UK in 2011 and subjected to four B treatments (0·00, 1·35, 1·80 and 2·70 kg B/ha). The results confirmed that BH incidence and severity was affected by genotype but could be ameliorated by B application. Genotype Ag31 was very susceptible while Or13 and Me77c were of intermediate susceptibility and the hybrids between susceptible parents were also sensitive. Genotypes Gr19 and Ly01 were highly resistant even in the absence of B application. Hybrids between resistant and susceptible lines were highly resistant. The use of ms had no influence on BH. Resistance to BH was a dominant trait: homozygous dominant (BHBH) or heterozygous (BHbh) genotypes confer this trait, while susceptibility is recessive (bhbh). Some quantitative variation existed, suggesting that resistance was not a single gene effect. There was a significant negative correlation (r=−0·632) between root B content and the severity of BH in susceptible genotypes. Severe BH was associated with 12–21·5 μg B/g of root dry weight at zero B applied. Moderate discolouration was associated with 19·5–24·8 μg B/g recorded at moderate B applied and only Ag31 showed BH at 2·70 kg B/ha. Resistant varieties had root contents of 23 μg B/g or more while susceptible varieties required a minimum of 31 μg B/g to offset BH.


2020 ◽  
pp. 1-15
Author(s):  
Amit J. Jhala ◽  
Jason K. Norsworthy ◽  
Zahoor A. Ganie ◽  
Lynn M. Sosnoskie ◽  
Hugh J. Beckie ◽  
...  

Abstract Pollen-mediated gene flow (PMGF) refers to the transfer of genetic information (alleles) from one plant to another compatible plant. With the evolution of herbicide-resistant (HR) weeds, PMGF plays an important role in the transfer of resistance alleles from HR to susceptible weeds; however, little attention is given to this topic. The objective of this work was to review reproductive biology, PMGF studies, and interspecific hybridization, as well as potential for herbicide resistance alleles to transfer in the economically important broadleaf weeds including common lambsquarters, giant ragweed, horseweed, kochia, Palmer amaranth, and waterhemp. The PMGF studies involving these species reveal that transfer of herbicide resistance alleles routinely occurs under field conditions and is influenced by several factors, such as reproductive biology, environment, and production practices. Interspecific hybridization studies within Amaranthus and Ambrosia spp. show that herbicide resistance allele transfer is possible between species of the same genus but at relatively low levels. The widespread occurrence of HR weed populations and high genetic diversity is at least partly due to PMGF, particularly in dioecious species such as Palmer amaranth and waterhemp compared with monoecious species such as common lambsquarters and horseweed. Prolific pollen production in giant ragweed contributes to PMGF. Kochia, a wind-pollinated species can efficiently disseminate herbicide resistance alleles via both PMGF and tumbleweed seed dispersal, resulting in widespread occurrence of multiple HR kochia populations. The findings from this review verify that intra- and interspecific gene flow can occur and, even at a low rate, could contribute to the rapid spread of herbicide resistance alleles. More research is needed to determine the role of PMGF in transferring multiple herbicide resistance alleles at the landscape level.


2021 ◽  
pp. 1-51
Author(s):  
Amit J. Jhala ◽  
Hugh J. Beckie ◽  
Carol Mallory-Smith ◽  
Marie Jasieniuk ◽  
Roberto Busi ◽  
...  

Abstract The objective of this paper was to review the reproductive biology, herbicide-resistant (HR) biotypes, pollen-mediated gene flow (PMGF), and potential for transfer of alleles from HR to susceptible grass weeds including barnyardgrass, creeping bentgrass, Italian ryegrass, johnsongrass, rigid (annual) ryegrass, and wild oats. The widespread occurrence of HR grass weeds is at least partly due to PMGF, particularly in obligate outcrossing species such as rigid ryegrass. Creeping bentgrass, a wind-pollinated turfgrass species, can efficiently disseminate herbicide resistance alleles via PMGF and movement of seeds and stolons. The genus Agrostis contains about 200 species, many of which are sexually compatible and produce naturally occurring hybrids as well as producing hybrids with species in the genus Polypogon. The self-incompatibility, extremely high outcrossing rate, and wind pollination in Italian ryegrass clearly point to PMGF as a major mechanism by which herbicide resistance alleles can spread across agricultural landscapes, resulting in abundant genetic variation within populations and low genetic differentiation among populations. Italian ryegrass can readily hybridize with perennial ryegrass and rigid ryegrass due to their similarity in chromosome numbers (2n=14), resulting in interspecific gene exchange. Johnsongrass, barnyardgrass, and wild oats are self-pollinated species, so the potential for PMGF is relatively low and limited to short distances; however, seeds can easily shatter upon maturity before crop harvest, leading to wider dispersal. The occurrence of PMGF in reviewed grass weed species, even at a low rate is greater than that of spontaneous mutations conferring herbicide resistance in weeds and thus can contribute to the spread of herbicide resistance alleles. This review indicates that the transfer of herbicide resistance alleles occurs under field conditions at varying levels depending on the grass weed species.


1992 ◽  
Vol 6 (3) ◽  
pp. 615-620 ◽  
Author(s):  
Jodie S. Holt

At least 57 weed species, including both dicots and monocots, have been reported to have biotypes selected for resistance to the triazine herbicides. In addition, at least 47 species have been reported to have biotypes resistant to one or more of 14 other herbicides or herbicide families. These herbicides include the aryloxyphenoxypropionics, bipyridiliums, dinitroanilines, phenoxys, substituted areas, and sulfonylureas, with two or more resistant biotypes each, as well as several other herbicides in which resistance is less well documented. Although evolved resistance presents a serious problem for chemical weed control, it has also offered new potential for transferring herbicide resistance to crop species. Mechanisms of resistance that are due to single or a few genes have become the focus of biotechnology, as the probability of their successful transfer to crop species is high.


Weed Science ◽  
2019 ◽  
Vol 67 (6) ◽  
pp. 605-612 ◽  
Author(s):  
Xiangying Liu ◽  
Shihai Xiang ◽  
Tao Zong ◽  
Guolan Ma ◽  
Lamei Wu ◽  
...  

AbstractThe widespread, rapid evolution of herbicide-resistant weeds is a serious and escalating agronomic problem worldwide. During China’s economic boom, the country became one of the most important herbicide producers and consumers in the world, and herbicide resistance has dramatically increased in the past decade and has become a serious threat to agriculture. Here, following an evidence-based PRISMA (preferred reporting items for systematic reviews and meta-analyses) approach, we carried out a systematic review to quantitatively assess herbicide resistance in China. Multiple weed species, including 26, 18, 11, 9, 5, 5, 4, and 3 species in rice (Oryza sativa L.), wheat (Triticum aestivum L.), soybean [Glycine max (L.) Merr.], corn (Zea mays L.), canola (Brassica napus L.), cotton (Gossypium hirsutum L.)., orchards, and peanut (Arachis hypogaea L.) fields, respectively, have developed herbicide resistance. Acetolactate synthase inhibitors, acetyl-CoA carboxylase inhibitors, and synthetic auxin herbicides are the most resistance-prone herbicides and are the most frequently used mechanisms of action, followed by 5-enolpyruvylshikimate-3-phosphate synthase inhibitors and protoporphyrinogen oxidase inhibitors. The lack of alternative herbicides to manage weeds that exhibit cross-resistance or multiple resistance (or both) is an emerging issue and poses one of the greatest threats challenging the crop production and food safety both in China and globally.


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