scholarly journals Soil Moisture and Temperature Effects on shrunken2 Sweet Corn Seed Decay and Seedling Blight Caused by Penicillium oxalicum

1996 ◽  
Vol 121 (1) ◽  
pp. 83-90 ◽  
Author(s):  
Nancy W. Callan ◽  
James B. Miller ◽  
Don E. Mathre ◽  
S. Krishna Mohan
Keyword(s):  
Soil Moisture ◽  
Fungal Pathogens ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Penicillium Oxalicum ◽  
Inoculum Density ◽  
Damping Off ◽  
Seedling Blight ◽  
Corn Seed ◽  
Seed Decay

Sweet corn (Zea mays L.) seed is commonly infected or infested with fungi that can impair stand establishment. Among these, Penicillium oxalicum Currie and Thorn is known to cause preemergence damping-off or postemergence seedling blight. Supersweet, or shrunken2 (sh2), sweet corn cultivars are particularly affected by seedborne fungal pathogens, although the effects of seed infection on seedling emergence and stand are variable under field conditions. This study was conducted to examine factors that could influence the impact of P. oxalicum on seedling stand, including P. oxalicum inoculum density on seed and in soil, soil moisture, soil temperature, and control of seed decay caused by soilborne Pythium ultimum Trow. Seed surface disinfestation usually had no effect on seedling stand under conditions favoring infection by P. ultimum. Inoculation of sh2 sweet corn seeds or infestation of soil with conidia of P. oxalicum resulted in increasing severity of damping-off and seedling blight as inoculum density increased. In pasteurized soil in the greenhouse, an inoculum density of 102 P. oxalicum conidia per seed reduced emergence and induced seedling blight. In the field, where P. ultimum was also a factor, 106 conidia per seed were needed to reduce emergence and 105 conidia per seed to reduce healthy seedling stand. When pythium seed decay was controlled by metalaxyl seed treatment, seedling emergence and healthy seedling stand were both reduced at 1 × 106 P. oxalicum conidia per seed. When sh2 sweet corn seed was inoculated with conidia of P. oxalicum and incubated in soil at subgermination moisture contents (4.2 to -7.8 MPa) for 2-4 weeks before planting and irrigating, P. oxalicum reduced seedling emergence at all soil moisture levels, but caused the greatest amount of injury after planting when seeds were incubated in soil above -5.1 MPa. As soil temperature increased from 9-25C, seedling emergence from seed inoculated with P. oxalicum was progressively reduced, with a decrease of nearly 50% at 25 C. Penicillium oxalicum has the greatest potential to reduce seedling stand when infected sweet corn seeds are planted in warm, dry soil, but the effects of this and other seedborne fungal pathogens may be masked under conditions favoring infection by P. ultimum.

scholarly journals FACTORS INFLUENCING PREEMERGENCE DAMPING-OFF AND SEEDLING BLIGHT OF SH-2 SWEET CORN CAUSED BY PENICILLIUM OXALICUM

HortScience ◽  
1994 ◽  
Vol 29 (7) ◽  
pp. 743b-743
Author(s):  
Nancy W. Callan ◽  
Don E. Mathre ◽  
James B. Miller
Keyword(s):  
Seed Germination ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Penicillium Oxalicum ◽  
Damping Off ◽  
Seedling Blight ◽  
Seedling Mortality ◽  
Factors Influencing ◽  
Visible Growth ◽  
Soil Temperatures

Penicillium oxalicum is a seed- and soilborne fungal pathogen that causes preemergence damping-off and postemergence seedling blight of sweet corn, While seed infection and infestation by P. oxalicum is common, the amount of injury observed in the field is variable. Our objective was to determine factors influencing the occurrence and severity of disease due to P. oxalicum. Inoculation of sh-2 sweet corn seeds with conidia of P. oxalicum reduced seedling emergence and resulted in seedling mortality. Disease severity in the greenhouse and the field was greater as inoculum density increased from ≈ 102 to 106 conidia per seed. Increasing soil temperatures after planting inoculated seed resulted in more preemergence damping-off. Penicillium oxalicum is capable of growth and sporulation in soil that is too dry for seed germination. Nontreated (naturally infected) sh-2 sweet corn seeds or seeds inoculated with P. oxalicum were incubated in pasteurized soil that had been adjusted to various moisture levels-all too low for seed germination. Increasing soil moisture was associated with visible growth of Penicillium spp. on seed after incubation, and greater levels of damping-off and seedling blight when the seed was planted.

scholarly journals FIELD PERFORMANCE OF BIO-PRIMING FOR PROTECTION OF sh2 SWEET CORN FROM PREEMERGENCE DAMPING-OFF CAUSED BY PYTHIUM ULTIMUM.

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1110f-1110
Author(s):  
Nancy W. Callan ◽  
James B. Miller ◽  
Don E. Mathre
Keyword(s):  
Pseudomonas Fluorescens ◽  
Seed Treatment ◽  
Field Experiments ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Field Performance ◽  
Pythium Ultimum ◽  
Damping Off ◽  
Corn Seed ◽  
Seed Bacterization

Shrunken-2 supersweet (sh2) sweet corn is susceptible to preemergence damping-off caused by Pythium ultimum, especially when planted into cold soil. Bio-priming, a seed treatment which combines the establishment of a bioprotectant on the seed with preplant seed hydration, was developed to protect seeds from damping-off.In a series of field experiments conducted in Montana's Bitterroot and Gallatin Valleys, bio-priming or seed bacterization with Pseudomonas fluorescens AB254 protected sweet corn from P. ultimum damping-off. Bio-priming corn seed with P. fluorescens AB254 was comparable to treatment with the fungicide metalaxyl in increasing seedling emergence. Seedlings from bio-primed seeds emerged from the soil more rapidly than from nontreated seeds and were larger at three weeks postplanting. Seeds of sh 2 and sugary enhancer (se) sweet corn, as well as that of several sh 2 cultivars, were protected from damping-off by bio-priming.

Effect of soil moisture and temperature on seedling emergence and incidence of Pythium damping-off in safflower (Carthamus tinctorius L.)

1995 ◽  
Vol 75 (2) ◽  
pp. 505-509 ◽  
Author(s):  
H.-H. Mündel ◽  
H. C. Huang ◽  
G. C. Kozub ◽  
D. J. S. Barr
Keyword(s):  
Soil Moisture ◽  
Seedling Emergence ◽  
Moisture Stress ◽  
Pythium Ultimum ◽  
Carthamus Tinctorius ◽  
Infested Soil ◽  
Damping Off ◽  
Seedling Blight ◽  
Sterile Soil ◽  
Canadian Prairies

The effects of soil moisture, soil temperature and Pythium ultimum Trow var. ultimum, on the emergence of safflower seedlings were investigated. The effect on emergence of safflower cultivar, Saffire, in Pythium-infested and in sterile soil was tested at three moisture stress levels (1500 kPa, 30 kPa, or 0 kPa), and five temperatures (5, 10, 15, 20, and 25 °C). Both factors affected emergence. At 0 kPa, emergence of safflower seedlings in both the Pythium-infested and sterile soil treatments averaged 4%. In sterile soil, at both 30 kPa and 1500 kPa, seedling emergence exceeded 85% at all temperatures. In Pythium-infested soil at 30 kPa, emergence was greater than 85% at 5 and 10 °C, but only 67, 49, and 27% at 15, 20 and 25 °C, respectively. Within the temperature range, 10–25 °C, seedling emergence in Pythium-infested soil was significantly less at 30 kPa than at 1500 kPa. In fields in the southern Canadian prairies infested with Pythium ultimum, safflower seeded into warm soil is likely to have poor stand establishment due to damping-off, especially if soil is wet. Thus it is advisable to plant safflower early, when soil is cool. Key words:Carthamus tinctorius, Pythium ultimum var. ultimum, Pythium sp. "group G", damping-off, seedling blight, soil moisture, temperature

scholarly journals Infusion of shrunken-2 Sweet Corn Seed with Organic Solvents: Effects on Germination and Vigor

HortScience ◽  
1992 ◽  
Vol 27 (5) ◽  
pp. 467-470 ◽  
Author(s):  
Patricia E. Hung ◽  
Vincent A. Fritz ◽  
Luther Waters
Keyword(s):  
Organic Solvents ◽  
Immersion Time ◽  
Sweet Corn ◽  
Stress Test ◽  
Dry Weight ◽  
Damping Off ◽  
Suitable Candidate ◽  
Corn Seed ◽  
Seed Mortality ◽  
Seed Rot

Sweet corn (Zea mays L. var. rugosa Bonaf.) seed carrying the mutant endosperm gene shrunken-2 (sh2) are very susceptible to seed rot and pre- and post-emergence damping off. Experiments were conducted to determine if selected organic solvents were suitable carriers for fungicide infusion of sh2 sweet corn seed for improved germination and stand establishment. Seed of `Florida Staysweet' and `Crisp-n-Sweet 710' were immersed in acetone, cyclohexane, decahydronaphthalene (Decalin), dimethylsulfoxide (DMSO), ethanol, or xylene for 5 seconds, 0.25, 0.50, 1.0, 2.0, 4.0, or 8.0 hours, air-dried, and subjected to a cold-stress test. Total germination and percentage of normal seedlings in both cultivars were significantly decreased after 8 hours of immersion in acetone. Average seedling dry weight, however, did not decrease. DMSO was highly toxic to both cultivars. Ethanol increased seed mortality with increasing immersion times. Cyclohexane, Decalin, and xylene caused erratic responses in all measured variables as immersion time increased. In a second experiment, the effects of immersion time up to 4 hours in acetone on germination and vigor of 11 sh2 cultivars were compared. There was no correlation between cultivar germination or vigor and immersion in acetone. Results indicate acetone could be used to infuse fungicides into the seed of some sh2 cultivars without compromising seed germination or vigor. However, each sh2 cultivar must be screened individually to determine if it is a suitable candidate for organic solvent infusion of fungicides.

scholarly journals Assessment of the physiological potential of super sweet corn seeds

2013 ◽  
Vol 35 (3) ◽  
pp. 340-346 ◽  
Author(s):  
Renata Oliveira Alvarenga ◽  
Julio Marcos-Filho ◽  
Tathiana Silva Timóteo
Keyword(s):  
Seed Quality ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Primary Root ◽  
Accelerated Aging ◽  
Cold Test ◽  
Seed Vigor ◽  
Corn Seed ◽  
Control Programs ◽  
Seedling Length

The assessment of physiological potential is essential in seed quality control programs. This study compared the sensitivity of different procedures for evaluating super sweet corn seed vigor, focusing on the primary root protrusion test. Six seed lots, each of the SWB 551 and SWB 585 hybrids, were used. Seed physiological potential was evaluated by germination and vigor tests (speed of germination, traditional and saturated salt accelerated aging, cold test, seedling length, seedling emergence and primary root protrusion). Primary root protrusion was evaluated every 12 hours at 15 °C, 20 °C and 25 °C using two criteria (primary root protrusion and seedlings at the 2 mm root stage). It was concluded that the primary root protrusion test at 15 °C can evaluate super sweet corn seed vigor by counting the number of seedlings at the 2 mm root stage.

scholarly journals Field Performance of Sweet Corn Seed Bio-primed and Coated with Pseudomonas fluorescens AB254

HortScience ◽  
1991 ◽  
Vol 26 (9) ◽  
pp. 1163-1165 ◽  
Author(s):  
Nancy W. Callan ◽  
Don E. Mathre ◽  
James B. Miller
Keyword(s):  
Pseudomonas Fluorescens ◽  
Seed Treatment ◽  
Field Experiments ◽  
Sweet Corn ◽  
Field Performance ◽  
Pythium Ultimum ◽  
Seedling Height ◽  
Damping Off ◽  
Corn Seed ◽  
Degree Of Protection

In field experiments, bio-priming and coating with Pseudomonas fluorescens AB254 consistently protected sweet corn (Zea mays L.) seeds from preemergence damping-off caused by Pythium ultimum Trow. The bio-priming seed treatment was evaluated under various disease pressures and with seeds of three sweet corn genotypes: shrunken-2 supersweet (sh-2), sugary enhancer (se), and sugary (su). While no damping-off occurred in the su sweet corn, bio-priming protected sh-2 and se sweet corn seeds at a level equivalent to that obtained by treatment with the fungicide metalaxyl. Biopriming increased seedling height of all three sweet corn genotypes at 4 weeks post-planting. Coating of sweet corn seeds with P. fluorescens AB254 provided an equivalent degree of protection from damping-off under all but the most severe conditions.

scholarly journals Evaluation of Major Ancestors of North American Soybean Cultivars for Resistance to Three Pythium Species that Cause Seedling Blight

Plant Disease ◽  
2018 ◽  
Vol 102 (11) ◽  
pp. 2241-2252 ◽  
Author(s):  
K. S. Rod ◽  
D. R. Walker ◽  
C. A. Bradley
Keyword(s):  
North American ◽  
Partial Resistance ◽  
Pythium Ultimum ◽  
The United States ◽  
Early Spring ◽  
Damping Off ◽  
Seedling Blight ◽  
Sources Of Resistance ◽  
Seed Decay ◽  
Resistant Lines

Pythium seedling blight, which can be caused by a number of Pythium spp., is a disease that affects soybean (Glycine max) in the United States and Canada. Pythium ultimum var. ultimum, one of the most common pathogenic species, is favored by cool, wet conditions in early spring and causes seed decay, root rot, and seedling damping-off. In all, 102 major ancestors of modern North American cultivars and “first progeny” cultivars developed directly from ancestral lines were evaluated for resistance to P. ultimum var. ultimum and two other species of Pythium in greenhouse assays. Several ancestors and first progeny cultivars, as well as the resistant check Archer, had varying levels of partial resistance to an Illinois isolate of P. ultimum var. ultimum. In a subsequent experiment, four of the most resistant lines (PI 84637, Maple Isle, Fiskeby III, and Fiskeby 840-7-3) and the susceptible cultivar Kanro were screened for resistance against isolates of P. irregulare and P. sylvaticum, and resistance to P. ultimum var. ultimum was confirmed. The lines that were partially resistant to P. ultimum var. ultimum in the first experiment were also partially resistant to P. irregulare and P. sylvaticum. The P. ultimum var. ultimum isolate was the most aggressive of the three isolates, followed by the P. irregulare and P. sylvaticum isolates. Modern cultivars descended from the soybean lines with partial resistance to these pathogens could be useful sources of resistance to Pythium seedling blight if they are found to have similar levels of resistance.

scholarly journals Presowing Seed Treatments to Enhance Supersweet Sweet Corn Seed and Seedling Quality

HortScience ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 277-278 ◽  
Author(s):  
Carlos A. Parera ◽  
Daniel J. Cantliffe
Keyword(s):  
Seed Treatment ◽  
Sweet Corn ◽  
Seedling Emergence ◽  
Solid Matrix ◽  
Seedling Vigor ◽  
Seed Treatments ◽  
Tetramethylthiuram Disulfide ◽  
Corn Seed ◽  
Presowing Treatment ◽  
Emergence Percentage

Poor emergence and low seedling vigor are characteristics of many supersweet sweet corn (Zea mays L.) cultivars carrying the shrunken-2 (sh2) gene. Four sh2 sweet corn cultivar seeds [`How Sweet It Is' (HSII), `Crisp N' Sweet 711' (CNS-711), `Sweet Belle' (SB), and `Dazzle' (DZ)] were solid-matrix-primed (SMP), SMP with sodium hypochlorite (SMPcl), treated with a fungicide combination (F) (Imazalil + Captan + Apron + Thiram), or primed with the aforementioned fungicides (SMPf). The seed treatments were tested in the laboratory and the field. Seed imbibition and leachate electrical conductivity were lower in SMP seeds than in nonprimed seeds. In the field, emergence percentage and rate of CNS-711 and SB (high-vigor seeds) were not improved by the seed treatments compared to the nontreated seeds. Emergence percentage and rate of HSII and DZ (considered low-vigor seeds) were improved as a result of SMPcl, SMPf, or F treatments compared to nonprimed seeds. Compared to the F treatment, the SMPcl presowing treatment increased DZ seedling emergence rate and percentage. The combined SMP and seed disinfection via NaOCl seems to be a promising fungicide seed-treatment substitute that improves the stand establishment and seedling vigor of sh2 sweet corn cultivars. Chemical names used: 1-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy)ethyl]-1 H imidazole (Imazalil); N-[(trichloromethyl)thio]-4-cyclohexene-1,2-dicarboximide(Captan); N- (2,6-dimethylphenyl)- N -(methoxyacetyl)alanine methyl ester (Apron); tetramethylthiuram disulfide (Thiram).

Effects of seed treatments and inoculum density of Fusarium avenaceum and Rhizoctonia solani on seedling blight and root rot of faba bean

2014 ◽  
Vol 94 (4) ◽  
pp. 693-700 ◽  
Author(s):  
K. F. Chang ◽  
R. L. Conner ◽  
S. F. Hwang ◽  
H. U. Ahmed ◽  
D. L. McLaren ◽  
...  
Keyword(s):  
Rhizoctonia Solani ◽  
Seed Yield ◽  
Faba Bean ◽  
Root Rot ◽  
Seed Treatment ◽  
Seedling Emergence ◽  
Inoculum Density ◽  
Fusarium Avenaceum ◽  
Seedling Blight ◽  
Seed Treatments

Chang, K. F., Conner, R. L., Hwang, S. F., Ahmed, H. U., McLaren, D. L., Gossen, B. D. and Turnbull, G. D. 2014. Effects of seed treatments and inoculum density of Fusarium avenaceum and Rhizoctonia solani on seedling blight and root rot of faba bean. Can. J. Plant Sci. 94: 693–700. Production of faba bean cultivars with tannin-free seed on the Canadian prairies has potential for use in human food and as a feedstock for livestock and aquaculture. However, root rot is a major constraint to production. The effects of fungicide seed treatments on root rot caused by Fusarium avenaceum and Rhizoctonia solani, and the effect of inoculum density on seedling emergence, nodulation, root rot severity and yield of faba bean were examined across 12 station years from 2009 to 2011 at sites in Manitoba and Alberta. Fusarium avenaceum reduced seedling emergence more than R.solani, but both pathogens had a similar impact on seed yield. The effects of inoculum density and seed treatment were generally significant for seedling emergence, root rot severity and seed yield for both pathogens. The interaction effects of inoculum density×seed treatment for F.avenaceum and R.solani were only significant for seed yield and seedling emergence. Seedling emergence and seed yield declined with increasing inoculum level for both F. avenaceum and R.solani. Fungicidal seed treatments with Apron Maxx (fludioxonil+metalaxyl) and Vitaflo 280 (carbathiin+thiram) consistently improved emergence and seed yield in trials inoculated with F.avenaceum or R.solani. This study demonstrated that seed treatment to manage root rot of faba bean is warranted.

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