Variation in tolerance mechanisms to fluazifop-P-butyl among selected zoysiagrass lines

Weed Science ◽  
2019 ◽  
Vol 67 (3) ◽  
pp. 288-295 ◽  
Author(s):  
Wenwen Liu ◽  
Gregory E. MacDonald ◽  
J. Bryan Unruh ◽  
Kevin E. Kenworthy ◽  
Laurie E. Trenholm ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Herbicide Tolerance ◽  
Acetyl Coa Carboxylase ◽  
Tolerance Mechanisms ◽  
Physiological Mechanisms ◽  
Breeding Programs ◽  
Susceptible Line ◽  
Metabolite Profiles ◽  
Biomass Reduction ◽  
New Cultivars

AbstractBreeding herbicide tolerance into new cultivars can improve safety and weed control in turfgrass systems. The sensitivity to fluazifop-P-butyl of 27 zoysiagrass (Zoysiaspp.) lines was screened under greenhouse conditions to identify potential tolerant germplasm for breeding programs. The herbicide rate that caused 50% biomass reduction (GR50) and the rate that caused 50% injury (ID50) were calculated to select the three most-tolerant and the five most-susceptible lines for studying the physiological mechanisms responsible for fluazifop-P-butyl tolerance. The differences in GR50and ID50between susceptible and tolerant lines ranged from 4-fold to more than 10-fold. Cytochrome P450–mediated metabolism was not detected in fluazifop-P-butyl–tolerant lines. Sequencing of theACCasegene confirmed that none of the seven previously reported mutations conferring resistance to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides in other species were present in any of the tolerant or susceptible zoysiagrass lines studied. An Ala-2073-Thr substitution was identified in two tolerant lines, but this mutation did not completely explain the tolerant phenotype. No clear differences in absorption and translocation rates of14C-radiolabeled fluazifop-P-butyl were observed among most lines, with the exception of a susceptible line that exhibited greater translocation than two of the tolerant lines. Metabolite profiles did not differ between tolerant and susceptible lines. Our results suggest that the diversity in tolerance to fluazifop-P-butyl in zoysiagrass germplasm is most likely the result of a combination of different, minor, additive non–target site mechanisms such as translocation rate and compartmentation after absorption.

scholarly journals Maize gene bank collections as potentially valuable breeding material

Genetika ◽  
2010 ◽  
Vol 42 (1) ◽  
pp. 9-21 ◽  
Author(s):  
Jelena Vancetovic ◽  
Snezana Mladenovic-Drinic ◽  
Milosav Babic ◽  
Dragana Ignjatovic-Micic ◽  
Violeta Andjelkovic
Keyword(s):  
Genetic Resources ◽  
Herbicide Tolerance ◽  
Gene Bank ◽  
Maize Breeding ◽  
Breeding Programs ◽  
Effective Utilization ◽  
Maize Populations ◽  
Predominant Type ◽  
Superior Genotypes ◽  
Maize Gene

Characterization and evaluation of the genetic resources provide breeders with valuable information on an effective utilization of the genetic resources in breeding programs. In this paper we present the results of different research programs aimed at identification of superior genotypes among MRI gene bank accessions, regarding stress tolerance (drought and herbicides), better nutritional quality (phosphorus) and specific traits (cytoplasmic male sterility - CMS). Fifty-two genotypes were identified as a potential source for drought tolerance. Considering herbicide tolerance only genotypes with resistance to the Pivot were found. Within 100 sources of CMS in the collection S cytoplasm was identified as the predominant type. Phytate analysis of 60 maize populations identified three groups of populations - with low (8), intermediate (25) and high (27) phytate content. The results of these researches, which are a part of pre-breeding activities, will be included in MRI breeding programs, with the aim of developing new genotypes with improved traits important in commercial maize breeding and seed production.

Nitrogen use efficiency: re-consideration of the bioengineering approach

Botany ◽  
2010 ◽  
Vol 88 (2) ◽  
pp. 103-109 ◽  
Author(s):  
Elizabeth K. Brauer ◽  
Barry J. Shelp
Keyword(s):  
Glutamate Synthase ◽  
Utilization Efficiency ◽  
Molecular Physiology ◽  
Physiological Mechanisms ◽  
Breeding Programs ◽  
Molecular Approaches ◽  
Starting Point ◽  
N Assimilation ◽  
Use Efficiency ◽  
N Use

There is considerable confusion about N use efficiency (NUE) in the plant literature. We would like to propose the simple and ubiquitous definitions described by Good et al. (2004) as a starting point for studies of NUE. Based on this terminology, there is evidence from breeding programs for variation in both uptake efficiency (UpE) and utilization efficiency (UtE). Molecular physiology studies typically address mechanisms for improving NUE, but often do not calculate NUE or even acquire appropriate data for calculating NUE. Herein, we report in detail on recent studies involving molecular approaches for improving NUE, and calculate changes in NUE where possible. The evidence suggests that there is potential for improving usage index and UpE in dicots and UpE and UtE in monocots by overexpressing enzymes for N assimilation, specifically glutamine synthetase 1, glutamate synthase, and alanine aminotransferase. If decreased fertilizer-N input and improved NUE are truly goals of the plant biology community, researchers are encouraged to (i) consider the use of both wild type and azygous controls, (ii) compare general NUE (on the basis of grain or biomass yield per unit of applied N) of overexpression mutants and controls at both limiting and non-limiting N levels, (iii) select an appropriate type of specific NUE for assessing the physiological mechanisms involved (uptake versus internal utilization), and (iv) confirm promising results under field conditions.

scholarly journals SWEETPOTATO FLAVOR - EXISTING STATUS AND FUTUREOUTLOOK

HortScience ◽  
1993 ◽  
Vol 28 (4) ◽  
pp. 262A-262
Author(s):  
J. Kays ◽  
Wayne J. McLaurin
Keyword(s):  
Genetic Diversity ◽  
Current Understanding ◽  
Breeding Programs ◽  
Flavor Chemistry ◽  
Staple Crops ◽  
Baked Potato ◽  
New Cultivars ◽  
Selection Of

Flavor is a primary trait in the selection of foods. The role of flavor in acceptance of the sweetpotato, flavors status as a selection trait in existing breeding programs, and our current understanding of the flavor chemistry of the sweetpotato was reviewed. The sweetpotato, unlike most staple crops, has a very distinct and dominant flavor. In typical breeding programs, however, flavor is generally one of the last traits screened. A tremendous diversity and range of flavors has been reported within the sweetpotato germplasm (e.g., acidic, bland, baked potato, boiled potato. carrot, chalky, chemical, citrus, earthy, Ipomoeo/terpene, lemon, musty, pumpkin, salty, squash (titer type), starchy, sweet, sweetpotato (traditional), terpene, and turnip. These results indicate that the genetic diversity for flavor present in sweetpotato germplasm will allow making substantial changes in the flavor of new cultivars, thus potentially opening previously unexploited or under-exploited markets. Implementation involves solving two primary problems: 1) identification of desirable flavor ideotypes; and development of procedures that allow maximizing the selection of specific flavor types.

scholarly journals Metabolome-based prediction of yield heterosis contributes to the breeding of elite rice

2019 ◽  
Vol 3 (1) ◽  
pp. e201900551
Author(s):  
Zhiwu Dan ◽  
Yunping Chen ◽  
Weibo Zhao ◽  
Qiong Wang ◽  
Wenchao Huang
Keyword(s):  
Population Structure ◽  
Predictive Models ◽  
Phenotypic Selection ◽  
Growth Conditions ◽  
Galactose Metabolism ◽  
Breeding Programs ◽  
Precision Breeding ◽  
Predictive Variables ◽  
Guide Field ◽  
Metabolite Profiles

Improvement of the breeding efficiencies of heterotic crops adaptive to different conditions can mitigate the food shortage crisis due to overpopulation and climate change. To date, diverse molecular markers have been used to guide field phenotypic selection, whereas accurate predictions of complex heterotic traits are rarely reported. Here, we present a practical metabolome-based strategy for predicting yield heterosis in rice. The dissection of population structure based on untargeted metabolite profiles as the initial critical step in multivariate modeling performed better than the screening of predictive variables. Then the assessment of each predictive variable’s contribution to predictive models according to all latent factors was more precise than the conventional first one. Metabolites belonging to specific pathways were closely associated with yield heterosis, and the up-regulation of galactose metabolism promoted robust yield heterosis in hybrids under different growth conditions. Our study demonstrates that metabolome-based predictive models with correctly dissected population structure and screened predictive variables can facilitate accurate predictions of yield heterosis and have great potential for establishing molecular marker–based precision breeding programs.

scholarly journals Herbicide Tolerance Mechanisms in Eastern Black Nightshade (Solanum ptycanthum)

HortScience ◽  
1996 ◽  
Vol 31 (4) ◽  
pp. 577d-577
Author(s):  
Vamsgita Kolasani ◽  
John Masiunas
Keyword(s):  
Herbicide Resistance ◽  
Herbicide Tolerance ◽  
Tolerance Mechanisms ◽  
Selected Lines ◽  
Eastern Black Nightshade ◽  
Solanum Ptycanthum ◽  
Black Nightshade ◽  
Paraquat Tolerance

Eastern black nightshade is one of the problematic weeds in vegetables and soybeans in the Midwest. It is representative of a rapidly growing complex of broadleaf weeds where herbicide resistance would be expected to occur. Eastern black nightshade calli lines that are resistant and susceptible to acifluorfen were maintained on the medium without the herbicide. After two years, these lines were tested for tolerance to acifluorfen and paraquat. Tolerance to acifluorfen was maintained in the previously selected lines. The lines were also cross tolerant to paraquat. Plants were regenerated from these calli lines and grown in the greenhouse. 14C-acifluorfen and 14C-paraquat uptake, translocation, and metabolism were studied.

scholarly journals Breeding tropical forages

2011 ◽  
Vol 11 (spe) ◽  
pp. 27-34 ◽  
Author(s):  
L Jank ◽  
CB Valle ◽  
RMS Resende
Keyword(s):  
Beef Cattle ◽  
Cattle Herd ◽  
Beef Production ◽  
Breeding Programs ◽  
Tropical Forage ◽  
The World ◽  
Tropical Forages ◽  
New Cultivars ◽  
Apomictic Reproduction

Brazil has the largest commercial beef cattle herd and is the main beef exporter in the world. Cultivated pastures are the basis for the Brazilian beef production, and occupy an area of 101.4 million hectares. However, very few forage cultivars are commercially available, and the majority of these are of apomictic reproduction, thus genetically homogeneous. Tropical forage breeding is at its infancy, but much investment and efforts have been applied in the last three decades and some new cultivars have been released. In this paper, origin of different species, modes of reproduction, breeding programs and targets are discussed and the resulting new cultivars released are presented.

Postemergence Herbicide Tolerance Variation in Peanut Germplasm

Weed Science ◽  
2015 ◽  
Vol 63 (2) ◽  
pp. 546-554 ◽  
Author(s):  
Ramon G. Leon ◽  
Barry L. Tillman
Keyword(s):  
Herbicide Tolerance ◽  
Dry Weight ◽  
Mechanisms Of Action ◽  
Breeding Programs ◽  
Breeding Lines ◽  
Mini Core Collection ◽  
Selection Strategies ◽  
Commercial Cultivars ◽  
Peanut Cultivars ◽  
Lower Tolerance

Although herbicide tolerance is not usually evaluated until the final stages of breeding programs, this trait is very important for grower adoption of new peanut cultivars. Understanding herbicide tolerance of breeding lines could help breeders develop selection strategies that maximize herbicide tolerance in new commercial cultivars. However, little is known about herbicide tolerance variability in peanut germplasm. Thirty-five randomly selected breeding lines from the peanut mini-core collection and cultivars ‘Florida-07’ and ‘Georgia-06G’ were evaluated for tolerance to 11 herbicides under greenhouse conditions. Variation among peanut lines in herbicide tolerance, measured as dry weight reductions (DWR), was similar across herbicides and was normally distributed. Florida-07 and Georgia-06G were in the lower two quartiles of injury and DWR among the evaluated peanut lines. Dose–response experiments showed that the most tolerant breeding lines had I50(the rate required to cause 50% injury) and GR50(the rate required to reduce dry weight 50%) values 0.4 to 2.5 times higher than the most susceptible lines, depending on the herbicide. A breeding line had a dicamba GR5013 times higher than the most susceptible line and 2.8 and 4.7 times higher than Florida-07 and Georgia-06G, respectively. The most tolerant lines were consistently tolerant to herbicides with different mechanisms of action, suggesting that nontarget site mechanisms are more likely to be responsible for the tolerance than target-site mutations. These results confirmed peanut-breeding programs would greatly benefit from screening breeding lines for tolerance to key herbicides and developing an herbicide-tolerance catalog. This information can be used when designing new crosses to reduce the risk of developing cultivars with low herbicide tolerance especially considering that one-half of the breeding lines exhibited lower tolerance than the commercial cultivars.

scholarly journals Genetic Basis for Varied Levels of Injury to Sweet Corn Hybrids from Three Cytochrome P450-metabolized Herbicides

2008 ◽  
Vol 133 (3) ◽  
pp. 438-447 ◽  
Author(s):  
Jerald K. Pataky ◽  
Michael D. Meyer ◽  
Joseph D. Bollman ◽  
Chris M. Boerboom ◽  
Martin M. Williams
Keyword(s):  
Cytochrome P450 ◽  
Sweet Corn ◽  
Herbicide Tolerance ◽  
Cooperative Extension Service ◽  
Corn Hybrids ◽  
University Of Wisconsin ◽  
Intermediate Response ◽  
Predicted Values ◽  
The University ◽  
Corn Hybrid

Some sweet corn (Zea mays L.) hybrids and inbreds can be severely injured or killed after postemergence applications of certain P450-metabolized herbicides. Consequently, existing hybrids are regularly evaluated for tolerance to new herbicides, and new hybrids are evaluated for tolerance to existing herbicides. In 2005 and 2006, the University of Wisconsin Cooperative Extension Service coordinated 12 trials in six states in which a total of 149 sweet corn hybrids were evaluated for tolerance to three cytochrome P450-metabolized herbicides: nicosulfuron, foramsulfuron, and mesotrione. Hybrid responses differed substantially within and among locations. The objective of this study was to determine if alleles affecting herbicide sensitivity (e.g., cytochrome P450 alleles) were associated with differences in levels of injury to sweet corn hybrids in these trials. Based on responses of F2 progeny to nicosulfuron, foramsulfuron, and mesotrione, 95 hybrids were classified as homozygous for alleles conditioning herbicide tolerance; 47 hybrids were classified as heterozygous with one allele each conditioning tolerance and sensitivity; and two hybrids were classified as homozygous for alleles conditioning sensitivity. When trial mean levels of injury after applications of mesotrione, nicosulfuron, and foramsulfuron in the herbicide trials were above 1%, 4%, and 5%, respectively, the response of the three genotypic classes of hybrids followed a consistent pattern. Homozygous-sensitive hybrids were injured most severely and often were killed by the two acetolactate synththase-inhibiting herbicides, nicosulfuron and foramsulfuron. Heterozygous hybrids had an intermediate response to all three herbicides that was more similar to homozygous-tolerant hybrids than homozygous-sensitive hybrids; however, injury to heterozygous hybrids was 1.5 to 2.3 times greater and significantly (P < 0.05) different from homozygous-tolerant hybrids based on t tests of group means and comparisons of predicted values from regressions of genotypic means on trial means. Based on responses of the 149 hybrids in this trial, the potential for and level of crop injury from use of nicosulfuron, mesotrione, and foramsulfuron on any specific sweet corn hybrid is conditioned largely by alleles at a single locus.

scholarly journals Heritability of Terbacil Herbicide Tolerance in Strawberry

HortScience ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 311-313
Author(s):  
C.A. Weber
Keyword(s):  
Recurrent Selection ◽  
Herbicide Tolerance ◽  
Significant Progress ◽  
Selection Procedures ◽  
Tert Butyl ◽  
Combining Abilities ◽  
Diallel Design ◽  
New Cultivars ◽  
Partial Diallel

A partial diallel design was used to investigate the inheritance of tolerance to terbacil herbicide in cultivated strawberry, Fragaria ×ananassa Duch. Two tolerant cultivars, `Honeoye' and `Earliglow', two moderately tolerant cultivars, `Lester' and `Allstar', and two susceptible cultivars, `Red Chief' and `Guardian' were used as parents to create populations that segregated for tolerance to the herbicide. Tolerance rankings of the populations closely coincided with expected rankings based on the published tolerance levels of parental cultivars. `Honeoye' and `Earliglow' derived populations had the highest average tolerance ratings, while `Guardian' derived populations had the lowest tolerance ratings. Heritability was estimated at h2 = 0.50, indicating that significant progress in increasing the tolerance of new cultivars to terbacil can be achieved through traditional recurrent selection procedures. General and specific combining abilities suggest that the tolerant cultivars in this study may be fixed in their tolerance and that increased mean tolerance will be most apparent in progenies combining tolerant and susceptible cultivars. As such, a broader pool of germplasm may be needed to develop cultivars that are more tolerant than those in this study. Chemical names: terbacil (3-tert-butyl-5-chloro-6-methyluracil)

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