STUDIES ON THE BIOLOGY OF WILD OATS. I. DORMANCY, GERMINATION AND EMERGENCE

1976 ◽  
Vol 56 (3) ◽  
pp. 611-618 ◽  
Author(s):  
M. P. SHARMA ◽  
W. H. VANDEN BORN ◽  
D. K. McBEATH
Keyword(s):  
Seedling Emergence ◽  
Control Program ◽  
Field Capacity ◽  
Kernel Weight ◽  
Wild Oat ◽  
Water Extracts ◽  
Percent Germination ◽  
Oat Seeds ◽  
Mature Seeds ◽  
Practical Implications

Mature seeds of wild oat (Avena fatua L.) from Alberta were completely dormant when freshly harvested. About 46% of the seeds lost their dormancy during storage for 33 wk at room temperature. Gibberellic acid was very effective in overcoming dormancy in freshly harvested or stored seeds. Water extracts from dormant wild oat seeds were more inhibitory than water extracts from non-dormant seeds to germination of wild oat seeds. A number of chemicals, viz., nitrates of potassium, ammonium and sodium, cytokinins (benzyladenine, kinetin), and thiourea, were effective to varying degrees in stimulating the germination and emergence of seeds. Percent germination and emergence of seedlings was maximum at temperatures ranging from 10 to 21 C, although germination and emergence were slower at 10 C than at the higher temperatures. A temperature of 32 C was detrimental to normal germination and emergence. Maximum seedling emergence occurred when soil moisture was maintained at 50 or 75% of the field capacity. At field capacity moisture levels, no seedlings emerged and nearly all the seeds had rotted within 11 days of planting. Planting depths of 2–8 cm were best for seedling emergence. From greater planting depths the rate and percent emergence were greater for larger seeds than for smaller or medium-sized seeds (separated on the basis of kernel weight). Time to maximum emergence was 8, 11–13 and 13–17 days from depths of 0.5–3 cm, 4–12 cm and 16–20 cm, respectively. Practical implications of some of these findings in a wild oat control program are discussed.

Growth Characteristics of Wild Oat (Avena fatua) in the Pacific Northwest

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 226-229 ◽  
Author(s):  
Larry A. Morrow ◽  
David R. Gealy
Keyword(s):  
Pacific Northwest ◽  
Avena Fatua ◽  
Field Conditions ◽  
Maximum Height ◽  
Wild Oat ◽  
The Pacific ◽  
Anther Extrusion ◽  
Oat Seeds ◽  
Mature Seeds ◽  
Number Of Seeds

Wild oat (Avena fatua L.) seedlings from mature seeds emerged in silt loam from depths up to 17.5 cm in the greenhouse or 15 cm under field conditions. No emergence occurred from greater depths. Under field conditions, the greatest percentage of shoots emerged from seeds planted 5 cm deep. Wild oat in a space-planted nursery produced an average of 19 tillers, reached a maximum height of 79 cm, and produced an average of 1072 seeds. The number of tillers per plant, the number of seeds per panicle, and the total number of seeds per plant increased with an increase in annual precipitation. Wild oat seeds harvested as early as 3 days after anther extrusion germinated, but seeds harvested 6 or 7 days after anther extrusion germinated more rapidly.

FACTORS INFLUENCING THE DEVELOPMENT OF PRIMARY DORMANCY IN WILD OAT SEEDS

1979 ◽  
Vol 59 (3) ◽  
pp. 777-784 ◽  
Author(s):  
STEVEN G. RICHARDSON
Keyword(s):  
Gibberellic Acid ◽  
Wild Oat ◽  
Night Temperature ◽  
Primary Dormancy ◽  
Factors Influencing ◽  
Seed Maturity ◽  
Oat Seeds ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Mature Seeds

Germination in response to gibberellic acid was used as an assay for wild oat seed dormancy. In growth chamber studies removal of glumes, a 5 °C reduction in night temperature (20 °C day/15 °C night vs. constant 20 °C), and a shorter photoperiod (12 vs. 18 h) during the period following panicle emergence reduced subsequent germination (increased dormancy) of mature seeds. Dormancy of field-grown wild oat seeds increased with increasing seed maturity and was affected by planting location and associated crop.

THE DORMANCY BEHAVIOR OF AVENA FATUA L. IN CULTIVATED SOIL

1962 ◽  
Vol 42 (1) ◽  
pp. 22-39 ◽  
Author(s):  
J. D. Banting
Keyword(s):  
Seed Dormancy ◽  
Clay Soil ◽  
Seedling Emergence ◽  
Wild Oat ◽  
Wild Oats ◽  
Heavy Clay ◽  
Oat Seeds ◽  
Viable Seeds ◽  
Dormancy Induction ◽  
Methods Of Control

Recovery of dormant, non-dormant and dead wild oat seeds and seedling emergence from naturally-infested Regina heavy clay soil was used as a measure of viability during 5 years of consecutive summerfallow subsequent to 13 years of continuous cropping.Percentage viability and dormancy corresponded closely throughout the first summerfallow period. By season’s end 33 per cent of the seeds were viable but mostly dormant. It was concluded that persistence was due primarily to seed dormancy and not lack of germinative conditions.Numerous seedlings emerged the following spring until early June when viability averaged 4 per cent. The potential value of delayed seeding methods of control was indicated clearly at this time. Persistence of seeds in the soil in the second and two succeeding summerfallow years was attributed largely to primary seed dormancy. Lack of moisture and oxygen contributed temporarily. There was little or no evidence of secondary dormancy induction under field conditions. Neither moisture nor oxygen supply appeared to seriously reduce total emergence in adjoining cropland. It was concluded that wild oats could be "grown out" equally well in a 2-year rotation of alternate crop and summerfallow as by means of 2 years of consecutive summerfallow if re-infestation was prevented during the crop year.Inhibition of germination of surface seeds, presumably by light, did not markedly prolong persistence of viable seeds in the soil. No viable seeds were found on the surface after June of the third summerfallow year.Results indicated that a minimum of 5 years is needed to elminate wild oats from heavy clay soils under cultivation.

Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems

2020 ◽  
pp. 1-22
Author(s):  
Michael J. Walsh ◽  
Annie E. Rayner ◽  
Annie Rutledge ◽  
John C. Broster
Keyword(s):  
Cropping Systems ◽  
Seedling Emergence ◽  
Field Studies ◽  
Wild Oat ◽  
Weed Seed ◽  
Weed Species ◽  
Environment Effect ◽  
Seed Survival ◽  
Cropping Seasons ◽  
Rigid Ryegrass

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).

Mechanical scarification technique breaks seed coat-mediated dormancy in wild oat (Avena fatua)

2021 ◽  
pp. 1-25
Author(s):  
Roberto Lujan Rocha ◽  
Yaseen Khalil ◽  
Aniruddha Maity ◽  
Hugh J. Beckie ◽  
Michael B. Ashworth
Keyword(s):  
Growth Rate ◽  
Seed Coat ◽  
Research Effort ◽  
Economic Losses ◽  
Wild Oat ◽  
Weed Species ◽  
Physical Dormancy ◽  
No Donor ◽  
Seedling Growth Rate ◽  
Oat Seeds

Abstract Wild oat is a herbicide resistance-prone global weed species that causes significant economic losses in dryland and horticultural agriculture. As a result, there has been a significant research effort in controlling this species. A major impediment to this research is the seed coat-mediated dormancy of wild oat, requiring a labor-intensive incision or puncturing of the seed coat to initiate seed germination. This study defines the most efficient settings of a mechanical thresher to overcome wild oat seed dormancy and then validates these settings using multiple populations collected from the Western Australian grain belt. We also compare the effects of rapid mechanical scarification and known germination stimulus tactics such as scarification with sulfuric acid (H2SO4), partial endosperm removal, sandpaper scarification of the seed coat, and immersion in sodium nitroprusside (NO donor SNP) solution on wild oat seedling growth rate. Threshing treatment of 1,500 rpm for 5 s provides equivalent germination compared with manually puncturing individual wild oat seeds, with no difference in seedling relative growth rate. The mechanical scarification of seeds using the thresher resulted in greater germination (66%) than H2SO4 scarification (0%), partial endosperm removal (10%), sandpaper seed coat scarification (25%), and exposure to NO donor SNP (34%). This study demonstrates that the physical dormancy of wild oat can be rapidly overcome using a commercially available mechanical thresher.

Effect of water on common lambsquarters (Chenopodium album L.) and barnyardgrass [Echinochloa crus-galli (L.) Beauv.] seedling emergence in corn

2002 ◽  
Vol 82 (4) ◽  
pp. 855-859 ◽  
Author(s):  
M. L. Leblanc ◽  
D. C. Cloutier ◽  
C. Hamel
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Chenopodium Album ◽  
Seedling Emergence ◽  
Field Capacity ◽  
Emergence Period ◽  
Common Lambsquarters ◽  
Weed Emergence

A 2-year field study was conducted in corn to determine the influence of rainfall, irrigation and soil water content on common lambsquarters and barnyardgrass emergence. Rainfall or irrigation had no influence on the final weed density and little on the pattern of weed emergence because the soil water content was at or greater than field capacity during the main weed emergence period. Irrigation may hasten the first weed emergence by warming the soil when temperature is limiting for germination. In southwestern Quebec, temperature appears to be the most important factor regulating germination in the spring since soil moisture is normally at field capacity for a long period, in part because of the melting of snow. Key words: Irrigation, weed emergence, soil moisture

scholarly journals Vigor tests in assessing the quality of signal grass seeds

2017 ◽  
Vol 38 (6) ◽  
pp. 3491
Author(s):  
Paulo Alexandre Fernandes Rodrigues de Melo ◽  
Tatiane Sanches Jeromini ◽  
Carlos Eduardo Affonso ◽  
Edna Ursulino Alves ◽  
Cibele Chalita Martins
Keyword(s):  
Germination Rate ◽  
Pearson Correlation ◽  
Seedling Emergence ◽  
Control Program ◽  
Brachiaria Brizantha ◽  
Quality Control Program ◽  
Market Requirements ◽  
Physiological Quality ◽  
Germination Vigor

The correct assessment of the physiological quality of seed lots is necessary for the quality control program of companies. For such purpose, tests that detect differences in the physiological potential of seed lots and that meet the minimum market requirements. Thus, the study was conducted towards assessing the efficiency of laboratory tests in differentiating the quality of Brachiaria brizantha cv. Xaraés seed lots. Seeds from nine lots were assessed regarding water content, germination, first germination count, electrical conductivity and seedling emergence in sand in the laboratory (normal seedlings, first count and germination rate index), and the results were compared with those from the seedling emergence test conducted in the field. The experimental design used was completely randomized, with four replicates, and the Pearson correlation coefficient between the values from the germination, vigor and field seedling emergence tests was determined. The germination and seedling emergence in sand tests and the seedling emergence rate index efficiently assess the physiological quality of Brachiaria brizantha cv. Xaraés seed lots, providing data similar to those from seedling emergence in the field.

Relationship between vigour tests and emergence of soybean when grown under a range of seedbed moisture conditions

1996 ◽  
Vol 36 (1) ◽  
pp. 93 ◽  
Author(s):  
SW Adkins ◽  
M Boersma ◽  
M Law
Keyword(s):  
Seedling Emergence ◽  
Accelerated Aging ◽  
Field Capacity ◽  
Hypocotyl Length ◽  
Accelerated Aging Test ◽  
Aging Test ◽  
Eastern Australia ◽  
Growth Room ◽  
Glycine Max L ◽  
Moisture Conditions

Laboratory vigour tests were performed on seed from 4 soybean [Glycine max (L.) Merr.] cultivars coming from commercial crops grown in eastern Australia. The seed from each cultivar had greater than 80% germination and a range in vigour. Vigour tests consisted of the accelerated aging (with or without a seed protectant, Thiram), cold, saturation and hypocotyl length tests. Results were compared with seedling emergence from the same cultivar when planted under growth room conditions (25/20 � 1�C, 14/10 h day/night) at 3 seedbed moisture levels (field capacity, -0.01 MPa; dry, -0.30 MPa; and saturated soil, soil saturated for 48 h, planted then allowed to dry to field capacity). The modified accelerated aging test with Thiram was significantly (P<0.01) correlated with emergence in all 3 seedbed moisture conditions. High vigour seed samples with high accelerated aging germinations emerged well. Overall, the vigour test which ranked the seed samples to give the best indicator of performance under a range of seedbed moisture conditions was the modified accelerated aging test with thiram.

Field-capacity water extracts from serpentine soils

Nature ◽  
1981 ◽  
Vol 294 (5838) ◽  
pp. 245-246 ◽  
Author(s):  
John Proctor ◽  
W. R. Johnston ◽  
D. A. Cottam ◽  
A. B. Wilson
Keyword(s):  
Field Capacity ◽  
Serpentine Soils ◽  
Water Extracts

Modeling site-specific wild oat (Avena fatua) emergence across a variable landscape

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 838-846 ◽  
Author(s):  
Eric R. Page ◽  
Robert S. Gallagher ◽  
Armen R. Kemanian ◽  
Hao Zhang ◽  
E. Patrick Fuerst
Keyword(s):  
Water Potential ◽  
Crop Residue ◽  
Seedling Emergence ◽  
Bare Soil ◽  
Slope Aspect ◽  
Weibull Function ◽  
Wild Oat ◽  
Site Specific ◽  
Wheat Field ◽  
The Impact

The spatial and temporal pattern of wild oat emergence in eastern Washington is affected by the steep, rolling hills that dominate this landscape. The objective of this study was to assess the impact of landscape position and crop residue on the emergence phenology of wild oat. Emergence of a natural wild oat infestation was characterized over two growing seasons (2003 and 2004), at two wheat residue levels (0 and 500 g m−2), and at five landscape positions differing in slope, aspect, and elevation in a no-till winter wheat field. Wild oat emerged 1 to 2 wk earlier at south-facing landscape positions than at north-facing landscape positions. Crop residue delayed wild oat emergence by 7 to 13 d relative to bare soil at south-facing positions in 2003 and had a reduced effect on emergence at north-facing landscape positions. Therefore, preserving surface residues tended to synchronize emergence across the landscape and may facilitate better timing of weed control where residue is present. Emergence of wild oat was modeled as a function of thermal time adjusted by water potential using a Weibull function. Temperature explained more variation in the model than water potential. This model explained much of the variability in wild oat emergence among landscape positions over these 2 yr and may be useful as a tool to predict the timing of wild oat emergence. Results also indicate that site-specific modeling is a plausible approach to improving prediction of weed seedling emergence.

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