The interrelation of burr burial, seed yield and dormancy in strains of subterranean clover

1976 ◽  
Vol 27 (6) ◽  
pp. 787 ◽  
Author(s):  
WJ Collins ◽  
CM Francis ◽  
BJ Quinlivan
Keyword(s):  
Seed Weight ◽  
Initial Level ◽  
Seed Viability ◽  
Selection Criterion ◽  
Subterranean Clover ◽  
Viable Seed ◽  
Individual Seed ◽  
Wide Range ◽  
Embryo Dormancy ◽  
Simple Selection

Prevention of burr burial drastically reduced the yield of viable seed in subterranean clover. This occurred through reductions in total burr number, number of mature burrs, number of seeds per burr, individual seed weight and seed viability. Strains differed markedly in their ability to produce seed in unburied burrs. A simple selection criterion based on changes in individual seed weight was proposed as a guide to screening for this character. When this criterion was applied to a wide range of strains, it appeared that later-maturing types were the most capable at producing seed in unburied burrs. The initial level of hardseededness was lower in seed from unburied burrs; also the rate of breakdown of hardseededness was faster in this seed, although the size of the effect varied between strains. Defoliation during the flowering period increased the initial level of hardseededness in seed from both buried and unburied burrs. Seed produced in buried burrs generally had a faster rate of breakdown of embryo dormancy than seed from unburied burrs, although the response varied between strains. The implications of these findings for future breeding and improvement in subterranean clover are discussed.

Embryo dormancy in subterranean clover seeds. I. Environmental control

1971 ◽  
Vol 22 (4) ◽  
pp. 599 ◽  
Author(s):  
BJ Quinlivan ◽  
HI Nicol
Keyword(s):  
Temperature Change ◽  
Temperature Regime ◽  
Initial Level ◽  
Environmental Control ◽  
Subterranean Clover ◽  
Trifolium Subterraneum ◽  
Moist Soil ◽  
Germination Inhibitors ◽  
Embryo Dormancy ◽  
Summer Temperatures

Embryo dormancy in seeds of subterranean clover (Trifolium subterraneum) is at a maximum at field maturity in the spring. High summer temperatures are the causative agent in the subsequent breakdown of embryo dormancy, the germination inhibitors in the seeds apparently being susceptible to heat. There is no evidence for germination inhibitors in the pod and burr material, nor is there any evidence to support the hypothesis of an environmentally imposed dormancy, for germination is relatively fast at 15 ? 25�C, a temperature regime equivalent to the daily temperature change of summer moist soil. There are differences between cultivars in the initial level of embryo dormancy and in the subsequent rate of breakdown.

Johnsongrass (Sorghum halepense) Management as Influenced by Herbicide Selection and Application Timing

2014 ◽  
Vol 28 (1) ◽  
pp. 142-150 ◽  
Author(s):  
Dennis B. Johnson ◽  
Jason K. Norsworthy
Keyword(s):  
Seed Weight ◽  
Field Experiments ◽  
Seed Viability ◽  
Sorghum Halepense ◽  
Viable Seed ◽  
Single Application ◽  
Application Timing ◽  
Boot Stage ◽  
Soil Seedbank ◽  
100 Seed Weight

Field experiments were conducted in 2009 and 2012 at Fayetteville, AR, to compare four herbicides across three application timings for johnsongrass control and to evaluate the effect of late-season herbicide applications on johnsongrass control, fecundity, seed viability, and progeny emergence. In the first experiment, glyphosate at 840 g ae ha−1and clethodim at 68 and 136 g ai ha−1provided 75 to 94% control of 15- to 60-cm tall johnsongrass and up to 98% stand reduction 4 wk after treatment (WAT). Glufosinate and nicosulfuron were generally effective on ≤30-cm tall johnsongrass; however, efficacy declined as johnsongrass size increased. In the second experiment, glyphosate at 840 g ha−1provided at least 89% johnsongrass control when applied at boot or after panicle emergence and up to 95% stand reduction 3 WAT. Applications of glyphosate at 420 and 840 g ha−1, clethodim at 68 and 136 g ha−1, and glufosinate at 740 g ai ha−1at the boot stage reduced viable seed production of treated plants 94 to 99%. Irrespective of rate, glyphosate and clethodim applied at boot stage reduced progeny emergence by 77 to 95% and 100-seed weight of treated plants 62 to 96% compared to the nontreated check. This research demonstrates the importance of herbicide selection, particularly for controlling johnsongrass plants larger than 30 cm. Additionally, the results demonstrate the benefits of a single application of glyphosate or clethodim at the boot stage of johnsongrass for decreasing the soil seedbank and reducing the success of johnsongrass progeny in future years.

The effect of burr burial on the seed of some early maturing subterranean clover cultivars

1971 ◽  
Vol 11 (48) ◽  
pp. 35 ◽  
Author(s):  
BJ Quinlivan ◽  
CM Francis
Keyword(s):  
Seed Development ◽  
Seed Weight ◽  
Seed Viability ◽  
Subterranean Clover ◽  
Soil Surface ◽  
Trifolium Subterraneum ◽  
Cultivar Differences ◽  
Seed Content ◽  
Early Maturing ◽  
Agricultural Regions

Seven early maturing cultivars of subterranean clover (Trifolium subterraneum) showed large between cultivar differences in terms of burr and seed development above the soil surface. The indices used for determining differences between buried and unburied burrs were burr and seed weight, and seed viability and impermeability. With all cultivars seed formed above the soil surface weighed less and had a lower viable and impermeable seed content. The results are discussed in terms of the selection and breeding of subterranean clover cultivars suitable for the low rainfall agricultural regions of Western Australia

scholarly journals Seed germination requirements of Hypericum scruglii, an endangered medicinal plant species of Sardinia (Italy)

Botany ◽  
2020 ◽  
Vol 98 (10) ◽  
pp. 615-621 ◽  
Author(s):  
Marco Porceddu ◽  
Martina Sanna ◽  
Sara Serra ◽  
Maria Manconi ◽  
Gianluigi Bacchetta
Keyword(s):  
Medicinal Plant ◽  
Seed Bank ◽  
Seed Viability ◽  
Base Temperature ◽  
Endemic Plant ◽  
Endangered Medicinal Plant ◽  
High Viability ◽  
Wide Range ◽  
Baseline Information ◽  
Germination Requirements

Hypericum scruglii Bacch., Brullo & Salmeri is an endangered endemic plant of Sardinia, and the phloroglucinol compounds identified in this species have been reported to inhibit the activity of the Human Immunodeficiency Virus. Seed banks are a genetic repository that effectively preserve taxa of conservation interest, and they hold knowledge about the biology and germination ecophysiology of the taxa they preserve. The main goals of this study were to investigate the germination requirements for H. scruglii, to evaluate the seed viability after eight years of long-term conservation and to suggest an efficient protocol for germination. Seeds stored at –25 °C in the seed bank were tested at temperatures from 5 to 30 °C and 25/10 °C. Base temperature (Tb) and thermal time (θ50) for germination were estimated. Seeds of H. scruglii germinated over a wide range of temperatures, responding positively to high temperatures and 25/10 °C. Tb was estimated at 4.92 °C, and θ50 was estimated at 198.27 degree days. The high viability detected in seeds of H. scruglii allows us to suggest the use of seeds stored in a seed bank when fresh material for plant propagation is scarce. Our results provide new and useful baseline information for implementing conservation and multiplication strategies for this endangered medicinal plant.

scholarly journals Do applications of systemic herbicides when green fruit are present prevent seed production or viability of Alliaria petiolata (garlic mustard)?

2021 ◽  
pp. 1-17
Author(s):  
Leo Roth ◽  
José Luiz C. S. Dias ◽  
Christopher Evans ◽  
Kevin Rohling ◽  
Mark Renz
Keyword(s):  
Seed Production ◽  
Seed Viability ◽  
Early Spring ◽  
Alliaria Petiolata ◽  
Late Spring ◽  
Garlic Mustard ◽  
Viable Seed ◽  
Application Timing ◽  
Control Seed ◽  
Second Year

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) postemergence to established, second-year A. petiolata populations at three locations when petals were dehiscing, and evaluated control, seed production and seed viability. Postemergence glyphosate applications at this timing provided 100% control of A. petiolata by 4 weeks after treatment at all locations whereas triclopyr efficacy was variable, providing 38-62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, we found a 71-99% reduction in number of viable seed produced plant-1 regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals were dehiscing is a viable alternative to cutting or hand-pulling at this timing as it substantially decreased viable A. petiolata seed production. Management Implications Postemergence glyphosate and triclopyr applications in the early spring to rosettes are standard treatments used to manage A. petiolata. However, weather and other priorities limit the window for management, forcing field practitioners to utilize more labor-intensive methods such as hand-pulling. It is not known how late in the development of A. petiolata these herbicides can be applied to prevent viable seed production. Since prevention of soil seedbank replenishment is a key management factor for effective long-term control of biennial invasive species, we hypothesized late spring foliar herbicide applications to second year A. petiolata plants when flower petals were dehiscing could be an effective management tool if seed production or viability is eliminated. Our study indicated that glyphosate applications at this timing provided 100% control of A. petiolata plants by 4 weeks after treatment at all locations, whereas triclopyr efficacy was inconsistent. Although both glyphosate and triclopyr decreased viable seed production to nearly zero at one of our three study locations, the same treatments produced significant amounts of viable seed at the other two locations. Our findings suggest late spring glyphosate and triclopyr applications should not be recommended over early spring applications to rosettes for A. petiolata management, as our late spring application timing did not prevent viable seed production, and may require multiple years of implementation to eradicate populations. Nonetheless, this application timing holds value in areas devoid of desirable understory vegetation compared to no management practices or mechanical management options including hand-pulling when fruit are present, as overall viable seed production was reduced to similar levels as these treatments.

scholarly journals Adriamycin - efficacy and possible adverse effects

2016 ◽  
Vol 17 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Agnieszka Pedrycz ◽  
Agnieszka Kramkowska
Keyword(s):  
Adverse Effects ◽  
Topoisomerase I ◽  
Myocardial Injury ◽  
Initial Level ◽  
Chemical Substance ◽  
Bilayer Membrane ◽  
Anticancer Effects ◽  
Wide Range ◽  
Knowledge Of Cancer ◽  
Pegylated Form

AbstractAdriamycin (doxorubicin) is a chemical substance in the anthracycline class with a wide range of applications in oncology and hematology. The mechanism of action of Adriamycin is related to formation of irregular bonds between nucleobases of DNA and inhibition of key enzymes of DNA synthesis - topoisomerase I and II as well as to formation of free radicals damaging DNA.A major limitation in the drug use is associated with its adverse effects such as cardiotoxicity and hepatotoxicity.The mechanism of myocardial injury by Adriamycin is linked to an increase in oxidative stress associated with impaired mitochondrial function and structure.Cardiotoxicity of anthracyclines is classified as: acute, chronic or late (delayed).Hepatotoxicity of Adriamycin as a damage of the liver is associated with a dysfunction of this organ. Adriamycin studies have shown increased level of transaminase present in 40% of patients treated with Adriamycin. The state was transient and asymptomatic, returning to the initial level even when treatment continued.Knowledge of cancer diseases contributed to a successive creation of two improved forms of Adriamycin (doxorubicin) – nonpegylated and pegylated formulas of the drug.The mechanism of anticancer effects of liposomal Adriamycin is similar to the mechanism of conventional Adriamycin, but placement of the molecules of active substance in liposomes has significant influence on the distribution of the drug.In order to increase the distribution of the drug, a special form of liposomal Adriamycin has been created by covering the surface of the liposomes with a hydrophilic polymer - (MPEG). This process, known as pegylation, decreases the interactions between the lipid bilayer membrane and the plasma components. Pegylated form of the drug is associated with a higher incidence of acute complications.

scholarly journals Flowering, Fecundity, Seed Germination, and Seed Viability of Viburnum opulus L. Cultivars

2009 ◽  
Vol 27 (1) ◽  
pp. 31-36
Author(s):  
Janine R. Conklin ◽  
James C. Sellmer
Keyword(s):  
Seed Germination ◽  
Seed Production ◽  
Seed Viability ◽  
Biological Traits ◽  
Limited Information ◽  
Viable Seed ◽  
Invasive Potential ◽  
Short Term ◽  
Viburnum Opulus ◽  
Tetrazolium Test

Abstract Mature specimens of Viburnum opulus and cultivars ‘Leonard's Dwarf’ and ‘Roseum’ were assessed over 2 years for flower and seed production, seed germination, and seed viability as determined by a tetrazolium test to understand their invasive potential. ‘Aureum’, ‘Compactum’, ‘Losely's Compact’, ‘Nanum’, and ‘Xanthocarpum’ were also tested for germination and viability of seeds. Cultivars differed in flower and seed production, seed germination, and seed viability. ‘Roseum’ prolifically produced highly viable seed that germinated at moderate rates under greenhouse conditions (8,354, 100%, and 73%, respectively). Viburnum opulus and ‘Leonard's Dwarf’ produced fewer viable seed which showed moderate to low germination rates (609, 100%, and 53%; 712, 100%, and 5%, respectively). ‘Aureum’ and ‘Xanthocarpum’ seeds germinated at moderate rates (55 and 25%, respectively) and were highly viable (100%). ‘Compactum’, ‘Losely's Compact’, and ‘Nanum’ germinated at low rates or failed to germinate (0, 0, and 5%, respectively), yet seeds were moderately viable (37, 65, and 55%, respectively). Seeds of all cultivars germinated at low rates or failed to germinate at both outdoor sites (0 to 5%) which suggests these plants may be weakly invasive. Short-term studies on biological traits such as these provide only limited information to assess the invasive potential of cultivars.

scholarly journals Phenotypic Characterization of 183 Turkish Common Bean Accessions for Agronomic, Trading, and Consumer-Preferred Plant Characteristics for Breeding Purposes

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 272 ◽  
Author(s):  
Muhammad Azhar Nadeem ◽  
Tolga Karaköy ◽  
Mehmet Zahit Yeken ◽  
Ephrem Habyarimana ◽  
Ruştu Hatipoğlu ◽  
...  
Keyword(s):  
Common Bean ◽  
Plant Height ◽  
Seed Yield ◽  
Environmental Conditions ◽  
Seed Weight ◽  
Seed Length ◽  
Plant Weight ◽  
Wide Range ◽  
Days To Maturity ◽  
100 Seed Weight

Plant landraces represent a repository of a gene pool, local adaptation of their domestic species, and thereby are considered a great source of genetic variations. Such genetic variation can be helpful to mitigate the current and future food challenges. A total of 183 common bean accessions including three commercial varieties collected from 19 Turkish provinces were grown to record their morpho-agronomic variations and to evaluate the best performing accessions under multi-environmental conditions. Plant height, days to maturity, pods weight, seed length, and 100-seed weight were used to evaluate the best performing accessions under different environmental conditions. A wide range of variations for traits like days to maturity (99–161), plant height (21–168.7 cm), seed length (7.41–16.4 mm), seeds per plant (17.8–254.4), and 100-seeds weight (24.97–73.8 g) were observed and can be useful for breeding purposes. The analytic results derived from the first three eigenvectors suggested that plant height, plant weight, 100-seed weight, and days to flowering were biologically significant bean traits. Seed yield per plant was positively and significantly correlated with plant weight and pods weight. Genotype × environment biplot discriminated the studied common bean accessions based on their plant height and growth habit. Plant height, days to maturity, seed width, and first pod height were found highly heritable traits and were least affected by environmental forces. Among 19 provinces, accessions of Bilecik showed maximum pods per plant, seed yield per plant and 100-seed weight, while Erzincan and Sivas provinces reflected the prevalence of bushy and early maturing accessions. Information provided herein comprehensively explored the occurrence of genotypic variations which can be used for the development of candidate varieties responding to breeder, farmer, and consumer preferences.

Seed-Mediated Gene Flow in Wheat: Seed Bank Longevity in Western Canada

Weed Science ◽  
2009 ◽  
Vol 57 (1) ◽  
pp. 124-132 ◽  
Author(s):  
Ryan L. Nielson ◽  
Marc A. McPherson ◽  
John T. O'Donovan ◽  
K. Neil Harker ◽  
Rong-Cai Yang ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Gene Flow ◽  
Seed Size ◽  
Spring Wheat ◽  
Seed Bank ◽  
Seed Viability ◽  
Wheat Crop ◽  
Western Canada ◽  
Viable Seed ◽  
Wheat Seed

Development of genetically modified (GM) wheat has raised concerns about the movement and persistence of transgenes in agroecosystems and the ability of growers to segregate GM from conventional wheat. Wheat as a crop has been studied extensively but the population biology of volunteer wheat is not well characterized. Artificial seed bank studies were conducted in western Canada to provide baseline data on volunteer wheat seed persistence. Seed from two cultivars of Canadian western red spring wheat, ‘AC Splendor’ and ‘AC Superb’, were buried in mesh bags at three depths (0, 2, and 15 cm) in two different environments in the fall of 2003 and 2004. In addition, in 2004, ‘AC Superb’ seed were separated into small and large seed lots and buried with a medium seed lot to examine the influence of seed size on seed bank persistence. Seeds were withdrawn at intervals to assess seed germination and viability and regression analysis conducted on the viable seed at each sample period, after burial. Seed viability was variable within years and sites, and declined exponentially over time. In the spring, approximately 6 mo after initiation, viable seed ranged from 1 to 43%. With the exception of a single site and year, seeds on the soil surface persisted significantly longer than buried seeds and increasing burial depth accelerated loss of viability. The maximum viability of wheat seeds at 0, 2, and 15 cm depth in the spring following planting was 43, 7, and 2%, respectively. The extinction of viability for 99% (EX99) of the seed was estimated from regression analysis. The EX99values of seeds buried at 0, 2, and 15 cm ranged from 493 to 1,114, 319 to 654, and 175 to 352 d after planting (DAP), respectively, with the exception of one site in 2003 where burial depths were not different and all had an EX99value of 456 DAP. Seed size and cultivar did not significantly affect persistence, with the exception of one site in 2003 where the difference in EX99values was 20 DAP. The rapid loss of seed viability limits temporal gene flow via volunteers in years following a wheat crop. Results provide data on spring wheat biology to aid in Canadian environmental biosafety assessments of GM wheat and will be incorporated into a mechanistic model to predict wheat gene flow on the Canadian prairies.

Effect of genotype and environment on pod wall proportion in white lupin: consequences to seed yield

1999 ◽  
Vol 50 (4) ◽  
pp. 575 ◽  
Author(s):  
L. C. Lagunes-Espinoza ◽  
C. Huyghe ◽  
J. Papineau ◽  
D. Pacault
Keyword(s):  
Genetic Correlation ◽  
Seed Yield ◽  
Seed Weight ◽  
Selection Criterion ◽  
White Lupin ◽  
Phenotypic Correlation ◽  
Genotypic Differences ◽  
Environmental Variance ◽  
Environment Effect ◽  
Pod Wall

One means of increasing seed yield in white lupin may be the modification of the harvest index in the reproductive compartment by a reduction of the proportion of pod walls. Genetic and environmental effects on the pod wall proportion and yield components were evaluated. Thirty-five genotypes of spring-sown material were sown in 6 different locations across France in 1996 and 1997, accounting for a total of 10 site × year combinations. The existence of a genetic variation for the pod wall proportion among studied genotypes was demonstrated (0.26–0.34). Highly significant genotypic differences for the pod wall proportion, seed number per pod, seed weight per pod, mean seed weight, flowering time, and seed yield were observed among lupin genotypes. The heritability of pod wall proportion was moderate, the phenotypic correlation between this character and seed yield was significant and negative, and the genetic correlation was high and negative. The environmental variance contributed a major part of the total variation. The genotype × environment effect for the pod wall proportion was small, which suggests that the selection of genotypes with low and stable pod wall proportion in different environments will be possible. The strong negative genetic correlation between pod wall proportion and seed yield supports the feasibility of using the character as a selection criterion for a higher seed yield.

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