scholarly journals Fecundity and Seed Dormancy Variation Within and Among Echinochloa Species

2021 ◽  
Vol 3 ◽  
Author(s):  
Hussain Tahir ◽  
Nilda Roma-Burgos
Keyword(s):  
Seed Production ◽  
Seed Dormancy ◽  
Room Temperature ◽  
Common Garden ◽  
Germination Capacity ◽  
Production Potential ◽  
High Germination ◽  
The Usa ◽  
Soil Seedbank ◽  
Multiple Species

The Echinochloa genus contains two of the world's top five worst weeds. The persistence and weediness of Echinochloa spp. are partly due to its seed longevity and variable seed dormancy. In the USA, specifically in Arkansas, multiple species infest the same field in many cases. Persistence could vary across species and dormancy affects infestation level. Studies were conducted to evaluate the seed production potential and dormancy of Echinochloa species in the State. Ninety-four accessions were characterized in a common garden in Fayetteville, Arkansas, USA. The species were Echinochloa colona (L.) Link, E. crus-galli (L.) P. Beauv, E. muricata P. Beauv and E. walteri (Pursh). Only one accession was identified as E. walteri and was excluded from data analysis. Seeds were after-ripened for 6 months at room temperature and germinated at 32°C day/23°C night with 12-h daylength. Germination was monitored for 14 d. The Echinochloa species in Arkansas were predominantly E. colona (78%). E. colona had the highest seed production and the lowest seed dormancy among species. Dormancy within each species varied greatly, especially for E. colona, with a germination capacity (GC) of 41–99%. Only 2.7% of 73 E. colona accessions were dormant. E. crus-galli had 56–79% GC; 33% of the accessions were dormant. E. muricata had 2–39% germination, with all accessions considered dormant. E. colona had the highest fecundity, with 72,973 seeds per plant. This was 2.3- and 2.6x higher than that of E. crus-galli and E. muricata, respectively. High seed production and high germination capacity must have contributed to the dominance of E. colona among other Echinochloa species. E. muricata is expected to persist longer in the soil seedbank compared to E. colona and E. crus-galli. Seed production, dormancy and longevity will affect interspecies population dynamics in response to management tactics.

Venice Mallow (Hibiscus trionum) Seed Production and Persistence in Soil in Colorado

1996 ◽  
Vol 10 (1) ◽  
pp. 22-28 ◽  
Author(s):  
Philip Westra ◽  
Calvin H. Pearson ◽  
Randal Ristau ◽  
Frank Schweissing
Keyword(s):  
Seed Production ◽  
Seed Dormancy ◽  
Seed Coat ◽  
Crop Production ◽  
Hard Seed ◽  
Hibiscus Trionum ◽  
Soil Seedbank ◽  
Hard Seed Coat ◽  
Insight Into

This study was conducted to gain insight into the soil seedbank dynamics of Venice mallow in two irrigated Colorado soils. Venice mallow plants produced an average of 3100 seeds per plant under noncompetitive irrigated conditions. Venice mallow seeds collected from three regions of Colorado and stored at 25 C averaged 95% dormancy and less than 4% nonviable seeds 6 mo after harvesting. Percent nonviable seeds in soil remained relatively constant over 2 yr. Most seeds germinated within the first 3 mo after burial in the first crop production year. Seed dormancy decreased to an average of 40% after 3 mo of burial in cultivated soil at Fruita and Rocky Ford, and thereafter remained relatively constant for 21 mo. Fruita seeds underwent lessin situgermination than seeds from Greeley or Rocky Ford. Innate seed dormancy was lower at Fruita (27%) than at Rocky Ford (39%). Enforced dormancy remained constant over a 21-mo period and was similar for both locations (32%). Seeds buried for 2 yr at Fruita underwent greaterin situgermination (42%) than at Rocky Ford (27%). At Fruita, the level of enforced dormancy was higher and the level of innate dormancy lower at the 20-cm than the 2-cm depths. Venice mallow seed dormancy likely is due to an impermeable hard seed coat.

Seed dormancy in four Tibetan Plateau Vicia species and characterization of physiological changes in response of seeds to environmental factors

2013 ◽  
Vol 23 (2) ◽  
pp. 133-140 ◽  
Author(s):  
Xiaowen Hu ◽  
Tingshan Li ◽  
Juan Wang ◽  
Yanrong Wang ◽  
Carol C. Baskin ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Seed Dormancy ◽  
Germination Rate ◽  
Soil Surface ◽  
The Tibetan Plateau ◽  
Physical Dormancy ◽  
High Germination ◽  
One Year ◽  
Hydrotime Model ◽  
Aba Biosynthesis

AbstractAlthough seed dormancy of temperate legumes is well understood, less is known about it in species that grow in subalpine/alpine areas. This study investigated dormancy and germination of four Vicia species from the Tibetan Plateau. Fresh seeds of V. sativa were permeable to water, whereas those of V. angustifolia, V. amoena and V. unijuga had physical dormancy (PY). One year of dry storage increased the proportion of impermeable seeds in V. angustifolia, but showed no effect on seed coat permeability in V. amoena or V. unijuga. Seeds of all four species also had non-deep physiological dormancy (PD), which was especially apparent in the two annuals at a high germination temperature (20°C). After 1 year of storage, PD had been lost. The hydrotime model showed that fresh seeds obtained a significantly higher median water potential [Ψb(50)] than stored seeds, implying that PD prevents germination in winter for seeds dispersed without PY when water availability is limited. After 6 months on the soil surface in the field, a high proportion of permeable seeds remained ungerminated, further suggesting that PD plays a key role in preventing germination after dispersal. Addition of fluridone, an inhibitor of abscisic acid (ABA) biosynthesis, evened-out the differences in germination between fresh and stored seeds, which points to the key role of ABA biosynthesis in maintaining dormancy. Further, fresh seeds were more sensitive to exogenous ABA than stored seeds, indicating that storage decreased embryo sensitivity to ABA. On the other hand, the gibberellic acid GA3 increased germination rate, which implies that embryo sensitivity to GA is also involved in seed dormancy regulation. This study showed that PY, PD or their combination (PY+PD) plays a key role in timing germination after dispersal, and that different intensities of dormancy occur among these four Vicia species from the Tibetan Plateau.

THE LOSS OF A GRAIN FUMIGANT MIXTURE OF CARBON TETRACHLORIDE AND CARBON BISULFIDE THROUGH SEALING AND VARIOUS COVERING MATERIALS

1987 ◽  
Vol 119 (6) ◽  
pp. 595-597
Author(s):  
S.R. Loschiavo ◽  
N.D.G. White
Keyword(s):  
Carbon Tetrachloride ◽  
Large Scale ◽  
Room Temperature ◽  
Fire Hazard ◽  
Stored Products ◽  
Stored Grain ◽  
The World ◽  
The Usa ◽  
Carbon Bisulfide ◽  
Low Toxicity

Fumigants that are liquid formulations at room temperature have been widely used to kill insects in stored products, containers, and soil. Carbon bisulfide was one of the first fumigants used on a large scale as early as 1869 and is still the main fumigant used in some parts of the world (Bond 1984). Carbon bisulfide is highly flammable (Fleming and Baker 1935) and is usually formulated with carbon tetrachloride to aid distribution of fumigants in grain masses (Berck 1958) and to reduce the fire hazard. Although carbon tetrachloride is of low toxicity to insects it causes extensive liver damage in humans (Rouiller 1964). Liquid fumigants were widely used to disinfest stored grain in the USA until recently (White et al. 1985), and are still used in many other parts of the world (FA0 1985).

scholarly journals Release of Medicago truncatula Gaertn. and Pisum sativum subsp. elatius (M. Bieb.) Asch. et Graebn. Seed Dormancy Tested in Soil Conditions

Agronomy ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1026
Author(s):  
Juan Pablo Renzi ◽  
Jan Brus ◽  
Stergios Pirintsos ◽  
László Erdős ◽  
Martin Duchoslav ◽  
...  
Keyword(s):  
Pisum Sativum ◽  
Medicago Truncatula ◽  
Seed Dormancy ◽  
Environmental Conditions ◽  
Common Garden ◽  
Soil Conditions ◽  
Bet Hedging ◽  
Soil Burial ◽  
Barrel Medic ◽  
Experimental Laboratory

Medicago truncatula (barrel medic) and Pisum sativum subsp. elatius (wild pea) accessions originating from variable environmental conditions in the Mediterranean basin were used to study physical seed dormancy (PY) release. The effect of soil burial on PY release was tested on 112 accessions of medic and 46 accessions of pea over the period of 3 months in situ at three common gardens (Hungary, Spain and Greece) from 2017 through 2019. PY release after soil exhumation followed by experimental laboratory germination of remaining dormant seeds (wet, 25 °C, 21 days) were related to the environmental conditions of the common garden and macroclimatic variables of the site of origin of the accessions. Higher PY release was observed in buried seeds under humid rather than under dry and hot environments. Exposure of remaining dormant seeds to experimental laboratory conditions increased total PY release up to 70% and 80% in barrel medic and wild pea, respectively. Wild pea showed higher phenotypic plasticity on PY release than barrel medic, which had higher bet-hedging within-season. Wild pea showed lower bet-hedging among-season (PY < 10%) in relation to precipitation than barrel medic, which was more conservative (PY ≈ 20%). Observed variability suggests that these species have the capability to cope with ongoing climate change.

scholarly journals Molecular regulation ofZmMs7required for maize male fertility and development of a dominant male-sterility system in multiple species

2020 ◽  
Vol 117 (38) ◽  
pp. 23499-23509 ◽  
Author(s):  
Xueli An ◽  
Biao Ma ◽  
Meijuan Duan ◽  
Zhenying Dong ◽  
Ruogu Liu ◽  
...  
Keyword(s):  
Male Sterility ◽  
Seed Production ◽  
Target Genes ◽  
Hybrid Seed ◽  
Molecular Regulation ◽  
Dominant Male ◽  
Hybrid Seed Production ◽  
Maize Breeding ◽  
Pollen Exine ◽  
Multiple Species

Understanding the molecular basis of male sterility and developing practical male-sterility systems are essential for heterosis utilization and commercial hybrid seed production in crops. Here, we report molecular regulation by genic male-sterility genemaize male sterility 7(ZmMs7) and its application for developing a dominant male-sterility system in multiple species.ZmMs7is specifically expressed in maize anthers, encodes a plant homeodomain (PHD) finger protein that functions as a transcriptional activator, and plays a key role in tapetal development and pollen exine formation. ZmMs7 can interact with maize nuclear factor Y (NF-Y) subunits to form ZmMs7-NF-YA6-YB2-YC9/12/15 protein complexes that activate target genes by directly binding to CCAAT box in their promoter regions. Premature expression ofZmMs7in maize by an anther-specific promoterp5126results in dominant and complete male sterility but normal vegetative growth and female fertility. Early expression ofZmMs7downstream genes induced by prematurely expressed ZmMs7 leads to abnormal tapetal development and pollen exine formation inp5126-ZmMs7maize lines. Thep5126-ZmMs7transgenic rice andArabidopsisplants display similar dominant male sterility. Meanwhile, themCherrygene coupled withp5126-ZmMs7facilitates the sorting of dominant sterility seeds based on fluorescent selection. In addition, both thems7-6007recessive male-sterility line andp5126-ZmMs7Mdominant male-sterility line are highly stable under different genetic germplasms and thus applicable for hybrid maize breeding. Together, our work provides insight into the mechanisms of anther and pollen development and a promising technology for hybrid seed production in crops.

Biology and management of Echinochloa colona and E. crus-galli in the northern grain regions of Australia

2019 ◽  
Vol 70 (11) ◽  
pp. 917 ◽  
Author(s):  
Asad Shabbir ◽  
Bhagirath S. Chauhan ◽  
Michael J. Walsh
Keyword(s):  
Seed Production ◽  
Seed Dormancy ◽  
Rapid Growth ◽  
Cropping Systems ◽  
Control Strategies ◽  
Yield Losses ◽  
Annual Grass ◽  
Fallow Management ◽  
Current Information ◽  
Wide Range

Echinochloa colona and E. crus-galli are two important annual grass weeds distributed throughout the summer cropping regions of Australia. Both species are highly problematic weeds, responsible for yield losses of up to 50% in summer grain crops. The success of Echinochloa species as weeds is attributed to their rapid growth, prolific seed production, seed dormancy and adaptability to a wide range of environments. Importantly, E. colona has evolved resistance to glyphosate in Australia, with resistant populations now widespread across the summer cropping regions. Fallow management of E. colona with glyphosate alone is risky in terms of increasing the chance of resistance and highly unsustainable; other control strategies (residual herbicides, strategic tillage, etc.) should be considered to complement herbicides. This review provides a summary of current information on the biology, ecology and management of Echinochloa species. The knowledge gaps and research opportunities identified will have pragmatic implications for the management of these species in Australian grain cropping systems.

scholarly journals Tolerance of Swallowworts (Vincetoxicum spp.) to Multiple Years of Artificial Defoliation and Clipping

2016 ◽  
Vol 9 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Lindsey R. Milbrath ◽  
Antonio DiTommaso ◽  
Jeromy Biazzo ◽  
Scott H. Morris
Keyword(s):  
North America ◽  
Seed Production ◽  
Aboveground Biomass ◽  
Root Biomass ◽  
Plant Competition ◽  
Common Garden ◽  
Plant Size ◽  
Tissue Loss ◽  
Defoliation Treatment ◽  
Growth And Reproduction

AbstractThe European vines pale swallowwort and black swallowwort are invading various habitats in northeastern North America. It is unclear how these plants might respond to potential biological control agents, as they experience little herbivore damage in North America, or longer durations of mowing given the reported lack of efficacy of mechanical control. We evaluated the effect of six seasons of artificial defoliation (50 or 100% defoliation once or twice per season) and clipping (once, twice, or four times at 8 cm above the soil level) on the survival, growth, and reproduction of mature plants of the two species grown in a common garden field experiment. No plants died from damage after 6 yr. Black swallowwort produced more aboveground biomass, whereas pale swallowwort produced more root biomass and root crown buds, compared with its congener species. For most damage treatments, root biomass and the number of crown buds and stems increased over time, whereas aboveground biomass and viable seeds per plant generally did not change. Substantial overlap in plant size and seed production occurred among damage treatments and species. The most severe defoliation treatment did not substantially limit growth and reproduction compared with undamaged plants. While two clippings per season sometimes prevented seed production, four clippings per season was the only type of damage that consistently prevented plant growth and eliminated seed production. Pale and black swallowwort display a high tolerance to aboveground tissue loss in high-light environments without plant competition. The annual increase in plant size calls into question the potential efficacy of a defoliating insect against field populations of swallowworts, and it seems likely the only benefits of a long-term mowing regime will be to eliminate seed production.

scholarly journals Recurrent outbreaks ofSalmonellaEnteritidis infections in a Texas restaurant: phage type 4 arrives in the United States

1996 ◽  
Vol 117 (1) ◽  
pp. 29-34 ◽  
Author(s):  
T. G. Boyce ◽  
D. Koo ◽  
D. L. Swerdlow ◽  
T. M. Gomez ◽  
B. Serrano ◽  
...  
Keyword(s):  
Room Temperature ◽  
Phage Type ◽  
El Paso ◽  
The United States ◽  
Control Group ◽  
Control Groups ◽  
Shell Eggs ◽  
Chinese Restaurant ◽  
The Usa ◽  
Safe Food

SummaryIn recent years infection caused bySalmonellaserotype Enteritidis (SE) phage type 4 has spread through Europe but has been uncommon in the USA. The first recognized outbreak of this strain in the USA occurred in a Chinese restaurant in El Paso, Texas, in April 1993; no source was identified. In September 1993, a second outbreak caused by SE phage type 4 was associated with the same restaurant. To determine the cause of the second outbreak, we compared food exposures of the 19 patients with that of two control groups. Egg rolls were the only item significantly associated with illness in both analyses (first control group: oddsratio [OR] 8·2, 95% confidence interval [CI] 2·3–31·6; second control group: OR 13·1, 95% CI 2·1–97·0). Retrospective analysis of the April outbreak also implicated egg rolls (OR 32·4, 95% CI 9·1–126·6). Egg roll batter was made from pooled shell eggs and was left at room temperature throughout the day. These two outbreaks of SE phage type 4 likely could have been prevented by using pasteurized eggs and safe food preparation practices.

scholarly journals Effects of season, altitude and daylength on floral initiation of two contrasting genotypes of Trifolium repens L.

1986 ◽  
Vol 106 (1) ◽  
pp. 149-154 ◽  
Author(s):  
F. Von Sury ◽  
J. Nösberger
Keyword(s):  
Low Temperature ◽  
Seed Production ◽  
Floral Initiation ◽  
Cool Season ◽  
Production Potential ◽  
Low Latitude ◽  
Specific Effects ◽  
Trifolium Repens L ◽  
Growth Chambers ◽  
Main Factors

SUMMARYThe effects of season and altitude on floral initiation of two Trifolium repena L. cultivars, Haifa and California Ladino, were tested in the area of Ayacucho, Peru (2730 m, 13° S), with regard to their seed production potential. Specific effects of daylength at a constant temperature (20 °C) were examined in growth chambers.In Ayacucho, the proportion of inflorescence-bearing nodes was found to be lowest between December and June (Haifa 10–20%, Ladino 0–10%) and highest in August (Haifa 30%) and September–October (Ladino 15%). Late in the cool season, floral initiation of Ladino, but not that of Haifa, increased strongly at a high altitude (3250 m). In growth chambers, Haifa initiated few inflorescences and Ladino none in a 10 h daylength. In 16 h, the floral initiation of Haifa was very limited but Ladino formed many inflorescences. Floral initiation of Haifa was most pronounced and lasted longest after a daylength shift from 10 to 13 h.It is concluded that seasonal and altitudinal variations in low temperature were the main factors influencing floral initiation in the region of Ayacucho. Haifa is considered to be an intermediate-day plant, suited for seed production in the region because of its marked and early flowering. Ladino was classified as a quantitative longday plant, unsuitable for seed production at this low latitude because of its retarded floral response to low temperature.

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