Emergence of wheat may be reduced by seed weather damage and azole fungicides and is related to coleoptile length

1988 ◽  
Vol 28 (2) ◽  
pp. 253 ◽  
Author(s):  
GM Murray ◽  
J Kuiper

Seed germination, seedling emergence and coleoptile length of sound and weather-damaged seed of 8 wheat cultivars, which had been treated with twice the recommended rates of the seed dressings Le-san E11, Pano-ram 25, Vitavax 750L, Baytan and Erex, were studied in a sand-perlite substrate at 13�C and in 2 field experiments. Germination was not affected by the dressings. Baytan and Erex delayed and reduced the emergence of all cultivars at 13�C, but in the field only some cultivars had emergence reduced by seed dressings. Weather damage reduced the germination of some cultivars but the results were not consistent. The emergence of damaged seed of some cultivars was further reduced by Baytan and Erex when sown deeply in dry soil. In the cvv. Banks and Osprey, weather damage and Erex shortened coleoptiles of seed that was germinated on moist soil in darkness at 13�C. Emergence was positively related with coleoptile length, and, in the controlled environment test, it declined markedly when coleoptiles were less than 5 cm.

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
RC. XIONG ◽  
Y. MA ◽  
HW. WU ◽  
WL. JIANG ◽  
XY. MA

ABSTRACT: Velvetleaf, an annual broadleaf weed, is a common and troublesome weed of cropping systems worldwide. Laboratory and field experiments were conducted to determine the effects of environmental factors on germination and emergence of velvetleaf. Seeds germinated over a range of constant temperatures from 10 to 40 oC regardless of light conditions, but no germination occurred at temperature below 5 oC and beyond 50 oC. Seeds germinated at alternating temperature regimes of 15/5 to 40/30 oC, with maximum germination (>90%) at alternating temperatures of 40/30 oC. Germination was sensitive to water stress, and only 0.4% of the seeds germinated at the osmotic potential of -0.4 MPa. There was no germination at ? 0.6 MPa. Moreover, germination was reduced by saline and alkaline stresses and no germination occurred at ³ 150 mM NaCl or ³ 200 mM NaHCO3 concentrations. However, pH values from 5 to 9 had no effect on seed germination. Seedling emergence was significantly affected by burial depth and maximum emergence (78.1-85.6%) occurred at the 1-4 cm depth. The results of this study have contributed to our understanding of the germination and emergence of velvetleaf and should enhance our ability to improve control strategies in cropping systems in central China.


Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 854-860 ◽  
Author(s):  
Bhagirath S. Chauhan ◽  
Gurjeet Gill ◽  
Christopher Preston

Annual sowthistle has become more abundant under no-till systems in southern Australia. Increased knowledge of germination biology of annual sowthistle would facilitate development of effective weed control programs. The effects of environmental factors on germination and emergence of annual sowthistle seeds were examined in laboratory and field experiments. Seeds of annual sowthistle were able to germinate over a broad range of temperatures (25/15, 20/12, and 15/9 C day/night temperatures). Seed germination was favored by light; however, some germination occurred in the dark as well. Greater than 90% of seeds germinated at a low level of salinity (40 mM NaCl), and some seeds germinated even at 160 mM NaCl (7.5%). Germination decreased from 95% to 11% as osmotic potential increased from 0 to −0.6 MPa and was completely inhibited at osmotic potential greater than −0.6 MPa. Seed germination was greater than 90% over a pH range of 5 to 8, but declined to 77% at pH 10. Seedling emergence was the greatest (77%) for seeds present on the soil surface but declined with depth, and no seedlings emerged from a soil depth of 5 cm. In another experiment in which seeds were after-ripened at different depths in a field, seed decay was greater on the soil surface than at 2 or 5 cm depth. At the end of the growing season, there was a much greater persistence of buried seed (32 to 42%) than seeds present on the soil surface (8%). Greater persistence of buried seed could be due to dormancy enforced by dark in this species.


HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 409-410 ◽  
Author(s):  
Glen A. Murray ◽  
Jerry B. Swensen ◽  
Gary Beaver

The effect of osmotic priming on onion (Allium cepa L.) seedling emergence was evaluated in the field and in a controlled environment at 15C. Seeds of onion cultivars Bronze Wonder, Challenger, Big Mac, and White Keeper were primed in a solution of 300 g polyethylene glycol 8000/liter for 7 days at 10C 1 to 2 weeks before being planted in Spring 1986 and Summer 1987. Time to 50% of maximum emergence (T) for seedlings from primed seeds averaged 10% to 12% less than for unprimed seeds in both seasons and in laboratory experiments. Maximum emergence was improved 7% by priming in one spring field experiment but not in the summer field experiments or in the laboratory. Differences in T among cultivars in the 1986 experiments were small and significant only in one laboratory experiment. In 1987, cultivar differences in T were significant but not consistent in all experiments. Cultivar T means from laboratory experiments were significantly (P = 0.05) correlated with those for field emergence in three of four experiments, but coefficients were low (r = 0.37 to r = 0.45). Values for maximum emergence in the laboratory were not correlated with maximum emergence in the field. Laboratory emergence tests at 15C were a poor predictor of field emergence. Seed priming may benefit establishment of spring-seeded onions emerging at soil temperatures ≤ 15C more than summer-seeded onions emerging in soils >24C.


Author(s):  
Hayati Akman

This study targeted to elucidate the effect of seed aging on germination and emergence rates with and shoot characteristics in wheat cultivars. For this purpose, different bread wheat cultivars stored for 7 years and non-stored were compared for coleoptile length, root mass, shoot mass, root length as well as germination and seedling emergence rates. Here, the evidence suggested that seed storage over a prolonged period affected root and Shoot growth, coleoptile length, seed germination, and seedling emergence rates adversely. By linking germination and emergence rates, the data presented here indicated that a reduction in emergence rate in long-term storage was higher than that in the germination rate. It was also found that there were significant variations among the wheat cultivars about investigated traits during long-term storage. However, the emergence rates of Kate A1 and Flamura 85 were not affected substantially by long-term storage. The study suggested future studies to focus on clarification of the process controlling natural seed aging as such knowledge allows clue the eventual consequences of long-term storage.


2018 ◽  
Vol 28 (4) ◽  
pp. 277-285 ◽  
Author(s):  
Filippo Guzzon ◽  
Simone Orsenigo ◽  
Maraeva Gianella ◽  
Jonas V. Müller ◽  
Ilda Vagge ◽  
...  

AbstractThe genus Aegilops belongs to the secondary gene pool of wheat and has great importance for wheat cultivar improvement. As a genus with only annual species, regeneration from seeds in Aegilops is crucial. In several species in Aegilops, spikes produce different seed morphs, both in size and germination patterns. However, little is known about the ecology of seed germination, nor about the seed longevity in this genus. Here we investigated the germination phenology of Ae. neglecta under laboratory and field conditions and assessed longevity of different seed morphs of five additional Aegilops species using controlled ageing tests. Large seeds were short-lived and germinated faster than small seeds in most of the species. Field experiments with Ae. neglecta showed that large seeds of the dimorphic pair germinated 3 months after dispersal in contrast to 14 months for smaller seeds. Differences in longevity were detected not only in dimorphic seed pairs, but also among seeds from different positions on the spike. Our results indicate that different longevities in seed morphs of Aegilops may reflect a different soil seed bank persistence, with smaller seeds able to maintain a higher viability after dispersal than larger ones, thereby spreading seedling emergence over two years. Differences of seed germination and longevities between seed morphs in Aegilops may have important implications for ex situ seed conservation and reinforce the hypothesis of a bet-hedging strategy in the germination ecology of this genus.


2016 ◽  
Vol 96 (5) ◽  
pp. 887-894 ◽  
Author(s):  
A. Moussavi ◽  
S.Z.H. Cici ◽  
C. Loucks ◽  
R.C. Van Acker

Taraxacum Kok-saghyz (L.E. Rodin) (TKS) is a natural source of rubber. There is a rising interest in TKS establishment as a new crop in Ontario. Trials were conducted at Simcoe and Guelph, Ontario between 2013 and 2014 to explore the possibility of establishing TKS plants from seed in fields in Ontario. The effects of seeding depth, watering regimes, polymer, and covering mulch on the recruitment of TKS were explored. It was found that TKS displays very low field recruitment levels regardless of treatment. KNO3 did not have any significant effect on TKS seed germination. Seedling emergence was greatest when seeds were placed on the soil surface and decreased with increasing seeding depth. Two years of field experiments highlighted that TKS seedlings recruit better in moderate conditions when the temperature is optimum for TKS germination (warm but not hot, <25 °C). TKS seedlings recruited better at Simcoe (with a sandy soil type) than at Guelph (with a loamy soil type). Overall, however, field recruitment from seed was low (15% at best) and these results suggest that establishing TKS from seed in Ontario fields remains a challenge.


2013 ◽  
Vol 23 (3) ◽  
pp. 189-198 ◽  
Author(s):  
Prabhakar Singh ◽  
Hesham M. Ibrahim ◽  
Markus Flury ◽  
William F. Schillinger ◽  
Thorsten Knappenberger

AbstractLow soil water potential limits or prevents germination and emergence of rainfed winter wheat (Triticum aestivum L.). This phenomenon is particularly pronounced in the winter wheat–summer fallow region of the US Inland Pacific Northwest, where wheat is routinely sown deep to reach moisture with 12–15 cm of soil covering the seed. Wide differences in seedling emergence among winter wheat cultivars have been reported, but few previous experiments have examined germination differences among cultivars as a function of water potential. The objective of our laboratory study was to quantify seed germination of five commonly sown winter wheat cultivars (Moro, Xerpha, Eltan, Buchanan and Finley) at seven water potentials, ranging from 0 to − 1.5 MPa. Germination was measured as a function of time for a period of 30 d. At higher water potentials (0 to − 0.5 MPa), all cultivars had germination of more than 90%. At the lowest water potentials ( − 1.0 to − 1.25 MPa), however, Moro consistently exceeded the other cultivars for speed and extent of germination, with total germination of 74% at − 1.0 MPa and 43% at − 1.25 MPa. Since its release in 1966, Moro has been sown by farmers when seed-zone water conditions are marginal. Scientists have long known that coleoptile length is an important factor controlling winter wheat seedling emergence from deep sowing depths. In addition to having a long coleoptile, our data suggest that Moro's known excellent emergence ability from deep sowing depths in dry soils can also be attributed to the ability to germinate at lower water potentials than other cultivars.


2011 ◽  
Vol 356-360 ◽  
pp. 2465-2472
Author(s):  
Fei Peng ◽  
Wataru Tsuji ◽  
Tao Wang ◽  
Atsushi Tsunekawa

Reaumuria songarica (Pall.) Maxim and Nitraria tangutorum Bobr. are two species growing on nebkhas in dune system. But N. tangutorum distributes more widely than R. songarica does. Sand burial and drought are two major disturbing factors in the field. Experiments were conducted under controlled conditions to investigate sand burial depth and simulated precipitation amount on seed germination, seedling emergence and seedling mass of the two shrubs to explain the dominance of N. tangutorum over R. songarica. Seeds were buried at 6 depths (0, 0.5, 1.5, 3, 5, 8 cm) and irrigated with 3 water regimes (5, 7, 10 mm) in plastic pots (8 cm in diameter and 11 cm in height) under the same light intensity and alternating temperature in an environment controlled growth chamber. R. songarica has a greater germination percentage than N. tangutorum under each burial depth with any water regime. R songarica seed germination increased with burial depth at each water regime and when depth is deeper than 1.5 cm all the seeds germinated under 7 and 10 mm water treatment. N. tangutorum seed germination increased until an optimal burial depth and then decreased. The optimal burial depth shifts with water regime. Seedling emergence of R songarica did not occur at depth deeper than 1.5 cm under any water regime. N. tangutorum seedling emergence maximized at 3, 1.5 and 0.5 cm with 5, 7 and 10 mm water supply regime respectively. Under all the treatments, N. tangutorum seedlings had larger dry mass than R. songarica seedlings. Higher N. tangutorum seedling emergence percentage and seedling mass with given water supply enhance its possibility to appear on nebkhas in the study area.


1970 ◽  
Vol 21 (3) ◽  
pp. 383 ◽  
Author(s):  
NJ Halse ◽  
RN Weir

Sixteen Australian wheat cultivars grown in controlled environment cabinets demonstrated a range of responses to seed vernalization varying from little or no promotion of floral initiation in Darkan, Kondut, Falcon, and Sunset to about 3 weeks in Festiguay, Claymore, and Mexico 120. Under short days (10 hr photoperiod v. 14 hr) or cold temperatures (12/7�C day/night v. 18/13�) the response to seed vernalization was reduced. None of the cultivars responsive to vernalization achieved floral initiation earlier under cold temperatures than under warm temperatures, even in the absence of seed vernalization. All cultivars achieved floral initiation earlier in long days but the magnitude of the response varied considerably among them. Long days similarly accelerated development from initiation to anthesis. Higher temperatures accelerated development to initiation and anthesis in all cultivars, with only minor differences in magnitude of response. Selected treatments in the cabinets gave rates of development to initiation which closely paralleled results for the same cultivars in field experiments. The number of spikelets per head varied considerably with cultivar, day length, and vernalization treatment. Within the range of conditions of the experiments, temperature did not affect spikelet number other than through vernalization. At either temperature, the spikelet number was closely and positively related to the number of days to floral initiation.


Weed Science ◽  
1985 ◽  
Vol 33 (2) ◽  
pp. 190-195 ◽  
Author(s):  
Mario R. Pareja ◽  
David W. Staniforth

Growth chamber and laboratory experiments evaluated the effects of seed-soil microsite characteristics on seed germination. When corn (Zea maysL. ‘Pioneer 3541’), soybean [Glycine max(L.) Merr. ‘Corsoy 79’], velvetleaf (Abutilon theophrastiMedic. ♯ ABUTH), and giant foxtail (Setaria faberiHerrm. ♯ SETFA) were seeded among soil aggregates 2.50 to 1.25 cm in diameter in the growth chamber, there was decreased seedling emergence with decreasing frequency of irrigation. These same species seeded inside artificial soil aggregates showed increased seedling emergence with decreasing frequency of irrigation. The germination of corn and soybean seed inside 0.4-g, fully moist soil aggregates incubated in the laboratory under high relative humidity conditions was significantly decreased relative to seed incubated in the absence of soil. Velvetleaf and giant foxtail germination was significantly reduced by 0.1-g soil aggregates. Rice (Oryza sativaL.) had 68% emergence from 1.0-g, fully moist soil aggregates, whereas larger seeded corn and soybean had only 20 and 10% emergence, respectively. Germination inhibition of giant foxtail seed by fully moist soil was partially reversed by incubating seed-containing aggregates in an atmosphere of 75% oxygen.


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