The effects of smut (Ustilago destruens) on seed production, dormancy, and viability in fall panicum (Panicum dichotomiflorum)

1995 ◽  
Vol 73 (10) ◽  
pp. 1628-1634 ◽  
Author(s):  
Thevaki Govinthasamy ◽  
Paul B. Cavers
Keyword(s):  
Key Words ◽  
Seed Production ◽  
Seed Dormancy ◽  
Seed Viability ◽  
Large Seed ◽  
Viable Seeds ◽  
Panicum Dichotomiflorum

Fall panicum (Panicum dichotomiflorum var. geniculatum), an abundant annual weed in southwestern Ontario, suffers large seed losses from the smut Ustilago destruens. From 19 to 83% of plants were infected in three sites surveyed. Some infected plants were completely sterile, but others produced small numbers of viable seeds. Most of these seeds did not give rise to smut-infected plants if they were not exposed to smut teliospores in the soil over winter. Compared with seeds from uninfected plants, those from infected plants had lower percent viability and weaker dormancy. When seeds from either infected or uninfected plants were mixed with smut teliospores over winter, 39% of the resulting plants were smut infected, compared with less than 1% of plants from seeds overwintered without smut teliospores. Seeds mixed with smut teliospores over winter did not lose viability, but some of them were slower to germinate the following spring. Key words: smut, fall panicum, seed viability, seed dormancy, germination, Ustilago destruens, Panicum dichotomiflorum.

The biology of Canadian weeds.: 97. Barbarea vulgaris R.Br.

1991 ◽  
Vol 71 (1) ◽  
pp. 149-166 ◽  
Author(s):  
Marilyn A. MacDonald ◽  
Paul B. Cavers
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Seed Production ◽  
Seed Dormancy ◽  
Rapid Growth ◽  
Barbarea Vulgaris ◽  
Weed Biology ◽  
Southern Ontario ◽  
Grain Crops ◽  
Disturbed Areas

Barbarea vulgaris R.Br. is an introduced weed of recently disturbed areas, small-seeded grain crops, roadsides and pastures. It is abundant in southern Ontario, Quebec and the northeastern U.S.A.; frequent in the Maritimes, British Columbia and the northwest coastal U.S.A.; and rare south of 33°N, north of 50°N and across the prairies. The weediness of this species largely results from its prolific seed production, enforced and induced seed dormancy, and its rapid growth under favourable conditions. Key words: Barbarea vulgaris, yellow rocket, weed biology

Seed production of Pinus sylvestris after release cutting

2000 ◽  
Vol 30 (6) ◽  
pp. 982-989 ◽  
Author(s):  
Christer Karlsson
Keyword(s):  
Pinus Sylvestris ◽  
Seed Production ◽  
Seed Quality ◽  
Seed Viability ◽  
Tree Height ◽  
Tree Age ◽  
Cone Production ◽  
Crown Length ◽  
Viable Seeds ◽  
Individual Trees

The effects of release cutting on cone, seed production, and seed quality were investigated in 1995-1996 among Scots pine (Pinus sylvestris L.) seed trees in central Sweden. The effects of diameter, height, crown length, and age of trees on cone production were also examined. Cone and seed production were about five times higher in seed trees that had been released for 4 or 5 years, compared with control trees in the unreleased forest. Seed trees released for less than 3 years had about the same level of cone production as the controls. After release, the number of cones increased more in the lower part of the tree crowns than in the uppermost 2 m. The mean 1000-seed weight, seed viability, and number of viable seeds per cone were not significantly different between released and unreleased trees. In 1996, there were about eight times more cones than in 1995, probably because summer temperatures were higher in 1994 than in 1993, the years when the respective flower buds were initiated. Within the investigated range of diameters, 250-430 mm at breast height, a 10-mm increase in diameter was correlated with a 10% increase in mean cone production. However, the variation in cone production between individual trees was considerable. Tree height, length of green crown, and tree age showed no significant correlations with cone production.

Effects of 2,4-D on Seed Production and Embryo Development of Curly Dock

Weed Science ◽  
1969 ◽  
Vol 17 (4) ◽  
pp. 533-536 ◽  
Author(s):  
M. A. Maun ◽  
P. B. Cavers
Keyword(s):  
Acetic Acid ◽  
Seed Production ◽  
Lithium Salt ◽  
Seed Viability ◽  
Rumex Crispus ◽  
Viable Seeds ◽  
Almost All ◽  
Dichlorophenoxy Acetic Acid ◽  
Days After Anthesis ◽  
Number Of Seeds

Lithium salt of (2,4-dichlorophenoxy)acetic acid (2,4-D) (1000 ppm) was sprayed on plants of curly dock (Rumex crispus L.) 12 days before anthesis, at an thesis, 7 days after anthesis, and 34 days after anthesis. Treatment 12 days before anthesis completely prevented the formation of viable seeds. Two percent of the seeds had minute embryos after treatment at anthesis, but even these seeds did not germinate. Embryos were present in 91% of the seeds from plants treated 7 days after anthesis. These embryos ranged in size from 0.5 to 2.5 mm. The total weight of seeds obtained was significantly less than the control and only 5 to 15% of these seeds were capable of germination. Spraying the inflorescences 34 days after anthesis did not affect the number of seeds produced or seed viability. Almost all plants remained alive after the harvest.

Impact of post-anthesis glyphosate on woolly cupgrass seed production, seed weight and seed viability

2015 ◽  
Vol 95 (6) ◽  
pp. 1193-1197 ◽  
Author(s):  
Robert E. Nurse ◽  
Stephen J. Darbyshire ◽  
Marie-Josée Simard
Keyword(s):  
Seed Production ◽  
Seed Weight ◽  
Soil Seed Bank ◽  
Seed Viability ◽  
Leaf Sheath ◽  
Embryo Viability ◽  
Weed Growth ◽  
Woolly Cupgrass ◽  
Eriochloa Villosa ◽  
Viable Seeds

Nurse, R. E., Darbyshire, S. J. and Simard, M.-J. 2015. Impact of post-anthesis glyphosate on woolly cupgrass seed production, seed weight and seed viability. Can. J. Plant Sci. 95: 1193–1197. Herbicides are generally applied at early stages of crop and weed growth to protect crop yield. Few studies have evaluated the effect of late (post-anthesis) applications of glyphosate as a management option to limit the seed production of weed escapes, such as woolly cupgrass (Eriochloa villosa). We propagated woolly cupgrass under greenhouse conditions and then applied three glyphosate treatments post-anthesis including: (1) an untreated control; (2) 900 g a.e. ha−1; and (3) 1800 g a.e. ha−1. Terminal inflorescences were collected 21 d after glyphosate application, and seed production, seed weight and embryo viability were assessed. Post-anthesis glyphosate applications did not influence seed production, but reduced seed weight and viability by 50 and 96%, respectively. Therefore, glyphosate applied just before the woolly cupgrass inflorescence begins to emerge from the leaf sheath (as late as the R1 stage in soybeans) is an effective strategy to manage woolly cupgrass reproduction and stop viable seeds from entering the soil seed bank or other dispersal pathways.

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 Fungal colonizers and seed loss in lodgepole pine orchards of British Columbia

Botany ◽  
2019 ◽  
Vol 97 (1) ◽  
pp. 23-33
Author(s):  
Paul Y. de la Bastide ◽  
Jonathon LeBlanc ◽  
Lisheng Kong ◽  
Terrie Finston ◽  
Emily M. May ◽  
...  
Keyword(s):  
British Columbia ◽  
Seed Production ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Seed Viability ◽  
Molecular Approaches ◽  
Seed Loss ◽  
Natural Range ◽  
Fungal Microbiome ◽  
Host Tissues

Lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) is an important lumber species in Canada, and seed orchards are expected to meet the increased demand for seed. However, seed production has been consistently low in the Okanagan region orchards of British Columbia, Canada. To determine whether the fungal microbiome contributes to seed loss, histological and molecular approaches were used. Seed production was studied at seven Okanagan orchards, all outside the natural range of lodgepole pine, and at one near Prince George, within its natural range. Seed losses were highest in the Okanagan, compared with Prince George. The role of fungal colonizers in consuming seed during the last stages of maturation is described. Fungal hyphae were frequently observed at all locations in developing seed, particularly once storage substances accumulated. Fungi identified from host tissues using molecular and morphological techniques included Alternaria, Cladosporium, Fusarium, Penicillium, and Sydowia. The opportunistic foliar pathogen Sydowia polyspora, which is known to have a variable biotrophic status, was detected at most orchards within different host tissues (seeds, needles, and conelets), in association with pollen, and in the air column. Reduced seed viability observed in Okanagan orchards is most likely due to a combination of factors, including composition of the fungal microbiome.

scholarly journals Potential Role of Sequential Glufosinate and Foramsulfuron Applications for Management of Fescues (Festucaspp.) in Wild Blueberry

2017 ◽  
Vol 31 (1) ◽  
pp. 100-110 ◽  
Author(s):  
Scott N. White ◽  
Shanthanu Krishna Kumar
Keyword(s):  
Field Study ◽  
Seed Production ◽  
Potential Role ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Early Spring ◽  
Seedling Mortality ◽  
Wild Blueberry

Sheep and hair fescue are perennial, tuft forming grasses that spread by seed and form dense sods in wild blueberry fields. These sods compete with the crop for resources and hinder harvest. Field and greenhouse studies were conducted in 2015 to evaluate 1) the effect of sequential glufosinate and foramsulfuron applications on suppression of fescues in the greenhouse and field, and 2) efficacy of glufosinate and foramsulfuron on fescue seedlings when applied at 2, 4, 6, and 8 wk after seedling emergence in the greenhouse. Glufosinate applications at 750 and 1,005 g ai ha−1followed by foramsulfuron application at 35 g ai ha−1reduced fescue leaf number and biomass relative to foramsulfuron application alone in the greenhouse. In the field study, fescue flowering tuft density, tuft inflorescence height, seed production, and seed viability were reduced by foramsulfuron alone, but there was a trend towards lower seed production and tuft height when fescues were treated with glufosinate at 1,005 g ha−1followed by foramsulfuron. Foramsulfuron caused low seedling mortality at all application timings evaluated, but glufosinate caused >90% mortality in seedlings when applied at 2, 4, 6, or 8 wk after seedling emergence. Our results suggest that sequential applications of these herbicides are less effective under field conditions relative to results obtained in the greenhouse, though burndown glufosinate applications may have a role in reducing fescue seedling recruitment. Additional research should be conducted to determine the effect of early spring and autumn glufosinate applications on fescue seedling recruitment and suppression of established fescue tufts with subsequent foramsulfuron applications.

scholarly journals Non-Deep Physiological Dormancy in Seed and Germination Requirements of Lysimachia coreana Nakai

Horticulturae ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 490
Author(s):  
Saeng Geul Baek ◽  
Jin Hyun Im ◽  
Myeong Ja Kwak ◽  
Cho Hee Park ◽  
Mi Hyun Lee ◽  
...  
Keyword(s):  
Seed Germination ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Seed Viability ◽  
Cold Stratification ◽  
Dormancy Breaking ◽  
Viability Test ◽  
Physiological Dormancy ◽  
Different Temperatures ◽  
Germination Requirements

This study aimed to determine the type of seed dormancy and to identify a suitable method of dormancy-breaking for an efficient seed viability test of Lysimachia coreana Nakai. To confirm the effect of gibberellic acid (GA3) on seed germination at different temperatures, germination tests were conducted at 5, 15, 20, 25, 20/10, and 25/15 °C (12/12 h, light/dark), using 1% agar with 100, 250, and 500 mg·L−1 GA3. Seeds were also stratified at 5 and 25/15 °C for 6 and 9 weeks, respectively, and then germinated at the same temperature. Seeds treated with GA3 demonstrated an increased germination rate (GR) at all temperatures except 5 °C. The highest GR was 82.0% at 25/15 °C and 250 mg·L−1 GA3 (4.8 times higher than the control (14.0%)). Additionally, GR increased after cold stratification, whereas seeds did not germinate after warm stratification at all temperatures. After cold stratification, the highest GR was 56.0% at 25/15 °C, which was lower than the GR observed after GA3 treatment. We hypothesized that L. coreana seeds have a non-deep physiological dormancy and concluded that 250 mg·L−1 GA3 treatment is more effective than cold stratification (9 weeks) for L. coreana seed-dormancy-breaking.

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 Effect of desiccation temperature on viability of immature dandelion (Taraxacum agg.) seeds dried in mowed inflorescences

2010 ◽  
Vol 56 (No. 12) ◽  
pp. 580-583 ◽  
Author(s):  
Z. Martinková ◽  
A. Honěk
Keyword(s):  
Seed Dispersal ◽  
High Temperatures ◽  
Seed Viability ◽  
Late Summer ◽  
Seed Maturation ◽  
Ripe Seed ◽  
Viable Seeds

After flowering has ceased, dandelion (Taraxacum agg.) capitula close to enable maturation of seeds. In late summer the period of seed maturation lasts for 9 days. The capitula mowed later than 4 days after the start of this period and desiccated at 25°C produce viable seeds. If cut and prostrated on insolated ground inflorescences can experience temperatures exceeding 50°C which may impair seed viability. We determined the effect of desiccation temperature (5, 15, 25, 35, 45 or 55°C) on viability of ripening seeds using inflorescences harvested on September 5, 2008 at Prague-Ruzyne (50°05'N, 14°18'09 E), five days after flowering ceased (about 4 days before seed dispersal). As control, ripe seeds were collected at dispersal on the same day and desiccated at identical temperatures. Desiccated seeds were germinated at constant 17°C. Ripening seeds of maturing capitula only remained germinable if desiccation temperatures were ≤ 35°C (optimum 25°C) and were killed at 45 and 55°C. The viability of ripe seed was not affected by any of the desiccation temperatures. Time of germination of 50% seeds that germinated was significantly shorter in ripe than ripening seeds. Exposure of mowed dandelion inflorescences on insolated ground (solarization) may thus decrease production of viable seeds because of high temperatures experienced during desiccation.  

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