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John J. Skvarla - One of the best experts on this subject based on the ideXlab platform.

  • Corroded exines from Havinga's Leaf Mold experiment — structure of Fagus and Quercus exines
    Review of Palaeobotany and Palynology, 1994
    Co-Authors: John R. Rowley, John J. Skvarla
    Abstract:

    Abstract Structure of exine units of Fagus sylvatica L. and Quercus robur L. became evident after six years in Leaf Mold. These exines appeared similar to those early in development and to exines on mature pollen following laboratory experiments involving Gunnar Erdtman's acetolysis plus plasma ashing or oxidation with potassium permanganate. In Fagus the rod-shaped exine units showed a difference in diameter from a minimum of 0.1 μm at distal ends to 0.3 μm or more basally. A core and an outer binder zone were evident in these units. Material in the core zone differed from the binder zone in having a weaker secondary electron signal. In Quercus , rods of exine unit structure were exposed. They were, like “experimentally” oxidized pollen, about 0.1 μm in diameter. In severely corroded pollen of Fagus the ectexine appeared to be entirely eroded except for the resistant exine units. Exine units appeared to originate from the endexine.

  • corroded exines from havinga s Leaf Mold experiment structure of fagus and quercus exines
    Review of Palaeobotany and Palynology, 1994
    Co-Authors: John R. Rowley, John J. Skvarla
    Abstract:

    Abstract Structure of exine units of Fagus sylvatica L. and Quercus robur L. became evident after six years in Leaf Mold. These exines appeared similar to those early in development and to exines on mature pollen following laboratory experiments involving Gunnar Erdtman's acetolysis plus plasma ashing or oxidation with potassium permanganate. In Fagus the rod-shaped exine units showed a difference in diameter from a minimum of 0.1 μm at distal ends to 0.3 μm or more basally. A core and an outer binder zone were evident in these units. Material in the core zone differed from the binder zone in having a weaker secondary electron signal. In Quercus , rods of exine unit structure were exposed. They were, like “experimentally” oxidized pollen, about 0.1 μm in diameter. In severely corroded pollen of Fagus the ectexine appeared to be entirely eroded except for the resistant exine units. Exine units appeared to originate from the endexine.

John R. Rowley - One of the best experts on this subject based on the ideXlab platform.

  • Corroded exines from Havinga's Leaf Mold experiment — structure of Fagus and Quercus exines
    Review of Palaeobotany and Palynology, 1994
    Co-Authors: John R. Rowley, John J. Skvarla
    Abstract:

    Abstract Structure of exine units of Fagus sylvatica L. and Quercus robur L. became evident after six years in Leaf Mold. These exines appeared similar to those early in development and to exines on mature pollen following laboratory experiments involving Gunnar Erdtman's acetolysis plus plasma ashing or oxidation with potassium permanganate. In Fagus the rod-shaped exine units showed a difference in diameter from a minimum of 0.1 μm at distal ends to 0.3 μm or more basally. A core and an outer binder zone were evident in these units. Material in the core zone differed from the binder zone in having a weaker secondary electron signal. In Quercus , rods of exine unit structure were exposed. They were, like “experimentally” oxidized pollen, about 0.1 μm in diameter. In severely corroded pollen of Fagus the ectexine appeared to be entirely eroded except for the resistant exine units. Exine units appeared to originate from the endexine.

  • corroded exines from havinga s Leaf Mold experiment structure of fagus and quercus exines
    Review of Palaeobotany and Palynology, 1994
    Co-Authors: John R. Rowley, John J. Skvarla
    Abstract:

    Abstract Structure of exine units of Fagus sylvatica L. and Quercus robur L. became evident after six years in Leaf Mold. These exines appeared similar to those early in development and to exines on mature pollen following laboratory experiments involving Gunnar Erdtman's acetolysis plus plasma ashing or oxidation with potassium permanganate. In Fagus the rod-shaped exine units showed a difference in diameter from a minimum of 0.1 μm at distal ends to 0.3 μm or more basally. A core and an outer binder zone were evident in these units. Material in the core zone differed from the binder zone in having a weaker secondary electron signal. In Quercus , rods of exine unit structure were exposed. They were, like “experimentally” oxidized pollen, about 0.1 μm in diameter. In severely corroded pollen of Fagus the ectexine appeared to be entirely eroded except for the resistant exine units. Exine units appeared to originate from the endexine.

T. C. Wang - One of the best experts on this subject based on the ideXlab platform.

  • Reactions of solanaceous species to Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold.
    Plant Disease, 1995
    Co-Authors: T. C. Wang, G. L. Hartman, W. H. Hsieh, L. L. Black
    Abstract:

    A total of 137 accessions representing 26 species and five genera of solanaceous plants were inoculated with Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold, under controlled conditions (growth room) and in the field. Twenty of 26 species developed symptoms after inoculation under controlled conditions. Black nightshade (Solanum nigrum) developed symptoms when inoculated under controlled conditions, but not in the field. Ground cherry (Physalis sp.), five Irish potato (Solanum tuberosum) cultivars, and eight tobacco (Nicotiana tabacum) lines remained symptomless following inoculation both under controlled conditions and in the field. Of 40 pepper accessions representing four species of Capsicum tested under controlled conditions, 32 developed lesions and eight were symptomless. Of 33 eggplant (Solanum melongena) accessions and related species representing seven Solanum spp. tested under controlled conditions, 24 developed symptoms and nine were symptomless. Two commercial eggplant cultivars, Pingtung Long and Farmers Long, were highly susceptible under controlled conditions and in the field. Among 46 Lycopersicon accessions representing 10 species that were evaluated, accessions of L. esculentum were the most susceptible and accessions of L hirsutum were the most resistant. Five Lycopersicon spp., three Solanum spp., and four Capsicum spp. are reported as new hosts of P. fuligena.

  • Inheritance of black Leaf Mold resistance in tomato
    Euphytica, 1995
    Co-Authors: T. C. Wang, L. L. Black, W. H. Hsieh, P. M. Hanson
    Abstract:

    Inheritance of black Leaf Mold (BLM) (caused by Pseudocercospora fuligena ) resistance was studied in four crosses involving two resistant Lycopersicon accessions (PI134417, L. hirsutum and PI254655, L. esculentum ) and four susceptible Asian Vegetable Research and Development Center tomato lines (CLN657BC_1F_2-267-0-3-12-7, CL143-0-10-3-0-1-10, CLN698BC_1F_2-358-4-13 and CL5915-93D_4-1-0-3). For each cross, six generations, i.e. P_1, P_2, F_1, F_2, BC_1F_1 and BC_1F_2 were evaluated following inoculations with isolate Pf-2 of P. fuligena . Chi-square analyses of the data based on the ratio of resistant to susceptible plants in the F_2 in three of four crosses gave a good fit to a segregation ratio of 1 R : 15 S, and BC_1F_2 data in three of four crosses gave an acceptable fit to the segregation ratio of 1 R : 63 S. The results indicate that resistance to BLM may be conditioned by two recessive genes acting epistatically in both PI134417 and PI254655.

  • Black Leaf Mold development and its effect on tomato yield.
    Plant Disease, 1992
    Co-Authors: G. L. Hartman, T. C. Wang
    Abstract:

    The severity of black Leaf Mold, caused by Pseudocercospora fuligena, was compared under epidemic conditions in field experiments on susceptible tomato lines that were either inoculated with the fungus or not inoculated. In one trial, 10 tomato entries that were infected by field inoculum had an average black Leaf Mold severity of 53 and 60% recorded over two assessments taken during fruit-set. In another experiment, different levels of disease severity were induced on a breeding line, CL 5915-153D 4 -3-3-0 (CL 5915) and a commercial variety, TN 2, by inoculating plants at various intervals(.)

G. L. Hartman - One of the best experts on this subject based on the ideXlab platform.

  • Reactions of solanaceous species to Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold.
    Plant Disease, 1995
    Co-Authors: T. C. Wang, G. L. Hartman, W. H. Hsieh, L. L. Black
    Abstract:

    A total of 137 accessions representing 26 species and five genera of solanaceous plants were inoculated with Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold, under controlled conditions (growth room) and in the field. Twenty of 26 species developed symptoms after inoculation under controlled conditions. Black nightshade (Solanum nigrum) developed symptoms when inoculated under controlled conditions, but not in the field. Ground cherry (Physalis sp.), five Irish potato (Solanum tuberosum) cultivars, and eight tobacco (Nicotiana tabacum) lines remained symptomless following inoculation both under controlled conditions and in the field. Of 40 pepper accessions representing four species of Capsicum tested under controlled conditions, 32 developed lesions and eight were symptomless. Of 33 eggplant (Solanum melongena) accessions and related species representing seven Solanum spp. tested under controlled conditions, 24 developed symptoms and nine were symptomless. Two commercial eggplant cultivars, Pingtung Long and Farmers Long, were highly susceptible under controlled conditions and in the field. Among 46 Lycopersicon accessions representing 10 species that were evaluated, accessions of L. esculentum were the most susceptible and accessions of L hirsutum were the most resistant. Five Lycopersicon spp., three Solanum spp., and four Capsicum spp. are reported as new hosts of P. fuligena.

  • Black Leaf Mold development and its effect on tomato yield.
    Plant Disease, 1992
    Co-Authors: G. L. Hartman, T. C. Wang
    Abstract:

    The severity of black Leaf Mold, caused by Pseudocercospora fuligena, was compared under epidemic conditions in field experiments on susceptible tomato lines that were either inoculated with the fungus or not inoculated. In one trial, 10 tomato entries that were infected by field inoculum had an average black Leaf Mold severity of 53 and 60% recorded over two assessments taken during fruit-set. In another experiment, different levels of disease severity were induced on a breeding line, CL 5915-153D 4 -3-3-0 (CL 5915) and a commercial variety, TN 2, by inoculating plants at various intervals(.)

L. L. Black - One of the best experts on this subject based on the ideXlab platform.

  • Inheritance of black Leaf Mold resistance in tomato
    Euphytica, 1995
    Co-Authors: T. C. Wang, L. L. Black, W. H. Hsieh, P. M. Hanson
    Abstract:

    Inheritance of black Leaf Mold (BLM) (caused by Pseudocercospora fuligena ) resistance was studied in four crosses involving two resistant Lycopersicon accessions (PI134417, L. hirsutum and PI254655, L. esculentum ) and four susceptible Asian Vegetable Research and Development Center tomato lines (CLN657BC_1F_2-267-0-3-12-7, CL143-0-10-3-0-1-10, CLN698BC_1F_2-358-4-13 and CL5915-93D_4-1-0-3). For each cross, six generations, i.e. P_1, P_2, F_1, F_2, BC_1F_1 and BC_1F_2 were evaluated following inoculations with isolate Pf-2 of P. fuligena . Chi-square analyses of the data based on the ratio of resistant to susceptible plants in the F_2 in three of four crosses gave a good fit to a segregation ratio of 1 R : 15 S, and BC_1F_2 data in three of four crosses gave an acceptable fit to the segregation ratio of 1 R : 63 S. The results indicate that resistance to BLM may be conditioned by two recessive genes acting epistatically in both PI134417 and PI254655.

  • Reactions of solanaceous species to Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold.
    Plant Disease, 1995
    Co-Authors: T. C. Wang, G. L. Hartman, W. H. Hsieh, L. L. Black
    Abstract:

    A total of 137 accessions representing 26 species and five genera of solanaceous plants were inoculated with Pseudocercospora fuligena, the causal agent of tomato black Leaf Mold, under controlled conditions (growth room) and in the field. Twenty of 26 species developed symptoms after inoculation under controlled conditions. Black nightshade (Solanum nigrum) developed symptoms when inoculated under controlled conditions, but not in the field. Ground cherry (Physalis sp.), five Irish potato (Solanum tuberosum) cultivars, and eight tobacco (Nicotiana tabacum) lines remained symptomless following inoculation both under controlled conditions and in the field. Of 40 pepper accessions representing four species of Capsicum tested under controlled conditions, 32 developed lesions and eight were symptomless. Of 33 eggplant (Solanum melongena) accessions and related species representing seven Solanum spp. tested under controlled conditions, 24 developed symptoms and nine were symptomless. Two commercial eggplant cultivars, Pingtung Long and Farmers Long, were highly susceptible under controlled conditions and in the field. Among 46 Lycopersicon accessions representing 10 species that were evaluated, accessions of L. esculentum were the most susceptible and accessions of L hirsutum were the most resistant. Five Lycopersicon spp., three Solanum spp., and four Capsicum spp. are reported as new hosts of P. fuligena.