Vernon Gracen

The Institute of Environment and Agricultural Research of Burkina Faso has extracted a large numb... more The Institute of Environment and Agricultural Research of Burkina Faso has extracted a large number of inbred lines from Open Pollinated Varieties, which are environmentally adapted and adopted by farmers. However, there is a gap in knowledge on heterotic grouping of these lines and their heterotic relationship with exotic lines. Twentyfour CIMMYT and INERA white lines were crossed to two CIMMYT testers and; twenty six IITA and INERA yellow inbred lines were crossed to two IITA testers. Two trials composed of 48 white testcrosses and 52 yellow testcrosses plus three checks were evaluated in well-watered and drought stress conditions in the dry season over two years. Significant general combining ability (GCA) effects due to lines and, testers for many traits including grain yield were observed. However, specific combining ability (SCA) effects for most traits except for plant and ear heights were not significant. Of the 24 CIMMYT and INERA white lines, 15 lines could be classified into heterotic groups based on the SCA effects and testcross mean grain yield in well-watered environment and, 10 lines were classified under drought stress condition. Eighty five percent of the IITA and INERA yellow lines were classified into heterotic groups in both drought and non-drought conditions. Thirteen yellow lines and five white lines maintained their heterotic groups in both well-watered and water-stressed conditions.

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Screening of Rice Accessions For Resistance to Rice Yellow Mottle Virus

American Journal of Experimental Agriculture, 2015

Leaf-feeding Resistance to the European Corn Borer in Genotypes of Tropical (Low-DIMBOA) and U.S. Inbred (High-DIMBOA) Maize

Journal of Economic Entomology, 1975

Abstract: Leaf-feeding and survival of 1st instar Ostrinia nubilalis Hübner) were studied using 5... more

Differential effects of digitonin on mitochondria isolated from male-sterile and non male-sterile cytoplasms of corn

Plant Science Letters, 1977

Mitochondria were isolated from corn roots containing T or C (male-sterile) cytoplasms and from N... more Mitochondria were isolated from corn roots containing T or C (male-sterile) cytoplasms and from N (non male-sterile) cytoplasm. The mitochondrial preparations (T, C and N mitochondria respectively) were treated with various concentrations of digitonin and assayed for respiratory activity. The T mitochondria were markedly more digitonin-sensitive than C or N mitochondria, as shown by the inhibition of malate and succinate respiration and uncoupling of oxidative phosphorylation. There were also differences between C and N mitochondria with respect to digitonin-sensitivity. These data strongly suggest that T, C and N mitochondria differ from each other with respect to biochemical structure. The chemical, genetic and agricultural signifance of these data is discussed.

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Resistance of Exotic Maize Varieties to the European Corn Borer Ostrinia nubilalis (Hubner)

Environmental Entomology, 1974

... These exotic lines had extremely little, if any, 2nd-generation damage to stalks, shank, or l... more

Bioassays for detection and quantification of Helminthosporium maydis race T-toxin: a comparison

Physiological Plant Pathology, 1977

ABSTRACT Sensitivities of seven commonly used bioassays for Helminthosporium maydis race T-toxin ... more ABSTRACT Sensitivities of seven commonly used bioassays for Helminthosporium maydis race T-toxin were determined. The most easily quantified and highly sensitive bioassays were based either on dark CO2 fixation by green leaves or on respiration rates of isolated mitochondria. These bioassays were 5 to 10 times more sensitive than was the semiquantitative seedling root growth bioassay. Bioassays based on the production of visible lesions on leaves did not provide reliable dosage-response relationships and were estimated to be 20 to 100 times less sensitive to toxin than dark CO2 fixation or mitochondrial respiration. Choice of bioassay depends on the objective of the experiment in which it is used.

Biochemical and cytological relationships in C4 plants

Planta, 1974

C 4 plants can be divided into three groups based on differences in activities of three decarboxy... more

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Effects of Purified Helminthosporium maydis Race T Toxin on the Structure and Function of Corn Mitochondria and Protoplasts

PLANT PHYSIOLOGY, 1980

A toxin preparation from Helminthosporium majdis Race T containing several closely related molecu... more A toxin preparation from Helminthosporium majdis Race T containing several closely related molecules with apparently identical biological activities was highly active against mitochondria and protoplasts from Texas male-sterile (T) cytoplasm corn (T mitochondria and T protoplasts, respectively) but had no effect on their male-fertile (N) cytoplasm counterparts. The toxin preparation caused multiple changes in isolated T mitochondria, including uncoupling of oxidative phosphorylation, stimulation of succinate and NADH respiration, inhibition of malate respiration, increased swelling, loss of matrix density, and unfolding of the inner membrane. Only 6 to 7 nanograms toxin per milligram mitochondrial protein (1.8 nanogram per milliliter) were required to fully uncouple oxidative phosphorylation and to completely inhibit malate respiration in isolated T mitochondria. Similar low concentrations of toxin caused collapse of T protoplasts after several days of culture. Severe ultrastructural damage to mitochondria in T protoplasts was observed within 20 minutes; no changes

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Evaluation of a Chemical Method for Assay of Helminthosporium maydis Race T Toxin

PLANT PHYSIOLOGY, 1977

A chemical test reported by Karr et al. (Plant Physiol. 55:727) to assay for host-specific toxin ... more A chemical test reported by Karr et al. (Plant Physiol. 55:727) to assay for host-specific toxin produced by Helminthosporium maydis race T was evaluated. Preparations from culture filtrates of both race T isolates, containing host-specific toxin, and similar preparations from race 0 isolates, containing no detectable host-specific toxin, gave positive reactions in the chemical assay. Also, preparations containing active or inactive toxin gave equal responses in this test. The procedure does not provide a reliable method for assaying H. maydis race T toxin.

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A Dominant Inhibitor Gene Inhibits the Expression of Ht2 against Exserohilum turcicum Race 2 in Corn Inbred Lines Related to B14

Plant Breeding, 1989

ABSTRACT The purpose of this study was to elucidate the genetic cause for the lack of express ion... more ABSTRACT The purpose of this study was to elucidate the genetic cause for the lack of express ion of the gene Ht2 against Exserohilum turcicum race 2 on certain genetic backgrounds related to the inbred line B14. Two such inbreds (A635Rp and B59), susceptible to this pathogen were crossed onto the inbred Oh43—-Ht2Ht2. The following generations: F1, F2, F3, F4, backcrosses to both parents, selfings of the backcrosses, in addition to the parent lines, were evaluated for Ht2 expression in this study. Plants of each generation were inoculated with E. turcicum race 2 and evaluated for the expression of the chlorotic-lesion resistance determined by the gene Ht2. In spite of the reported dominance of Ht2 on some genetic backgrounds, the F1 generations studied here did not show Ht2 resistant lesions. The data presented herein suggest that B14 and related inbred lines carry a dominant gene(I) that inhibits the expression of the Ht2 gene. Chi-square analyses of the reactions of 108 progeny families studied supported this hypothesis.

Yield and Plant Growth Responses of Mononychellus Mite Resistant and Susceptible Cassava Cultivars under Protected vs. Infested Conditions

Crop Science, 1982

A Comparative Analysis of Nuclear-determined Resistance to Helminthosporium maydis Races T and O in Maize1

Crop Science, 1979

Registration of NYLB31 and NYRD4058 Parental Lines of Maize

Crop Science, 1993

Effects of Helminthosporium maydis race T toxin on protoplasts of resistant and susceptible corn ( Zea mays )

Canadian Journal of Botany, 1975

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Role of Genetics in Etiological Phytopathology

Annual Review of Phytopathology, 1982

The Cytology of Pollen Abortion in S Cytoplasmic Male-Sterile Corn Anthers

American Journal of Botany, 1980

The Cytology of Pollen Abortion in C-Cytoplasmic Male-Sterile Corn Anthers

American Journal of Botany, 1979

Diversity assessment of drought tolerant exotic and adapted maize (Zea mays L.) inbred lines with microsatellite markers

Journal of Crop Science and Biotechnology, 2015

Farmers’ Perception and Impact of Rice Yellow Mottle Disease on Rice Yields in Burkina Faso

Agricultural Sciences, 2015

Panel Discussion: Plant Molecular Biology and Plant Breeding

Biotechnology in Plant Science, 1985

Heterotic relationship between INERA, CIMMYT and IITA maize inbred lines under drought and well-watered conditions

Maydica, 2014

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Screening of Rice Accessions For Resistance to Rice Yellow Mottle Virus

American Journal of Experimental Agriculture, 2015

Leaf-feeding Resistance to the European Corn Borer in Genotypes of Tropical (Low-DIMBOA) and U.S. Inbred (High-DIMBOA) Maize

Journal of Economic Entomology, 1975

Abstract: Leaf-feeding and survival of 1st instar Ostrinia nubilalis Hübner) were studied using 5... more

Differential effects of digitonin on mitochondria isolated from male-sterile and non male-sterile cytoplasms of corn

Plant Science Letters, 1977

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Resistance of Exotic Maize Varieties to the European Corn Borer Ostrinia nubilalis (Hubner)

Environmental Entomology, 1974

... These exotic lines had extremely little, if any, 2nd-generation damage to stalks, shank, or l... more

Bioassays for detection and quantification of Helminthosporium maydis race T-toxin: a comparison

Physiological Plant Pathology, 1977

Biochemical and cytological relationships in C4 plants

Planta, 1974

C 4 plants can be divided into three groups based on differences in activities of three decarboxy... more

Download

Effects of Purified Helminthosporium maydis Race T Toxin on the Structure and Function of Corn Mitochondria and Protoplasts

PLANT PHYSIOLOGY, 1980

Download

Evaluation of a Chemical Method for Assay of Helminthosporium maydis Race T Toxin

PLANT PHYSIOLOGY, 1977

Download

A Dominant Inhibitor Gene Inhibits the Expression of Ht2 against Exserohilum turcicum Race 2 in Corn Inbred Lines Related to B14

Plant Breeding, 1989

Yield and Plant Growth Responses of Mononychellus Mite Resistant and Susceptible Cassava Cultivars under Protected vs. Infested Conditions

Crop Science, 1982

A Comparative Analysis of Nuclear-determined Resistance to Helminthosporium maydis Races T and O in Maize1

Crop Science, 1979

Registration of NYLB31 and NYRD4058 Parental Lines of Maize

Crop Science, 1993

Effects of Helminthosporium maydis race T toxin on protoplasts of resistant and susceptible corn ( Zea mays )

Canadian Journal of Botany, 1975

Download

Role of Genetics in Etiological Phytopathology

Annual Review of Phytopathology, 1982

The Cytology of Pollen Abortion in S Cytoplasmic Male-Sterile Corn Anthers

American Journal of Botany, 1980

The Cytology of Pollen Abortion in C-Cytoplasmic Male-Sterile Corn Anthers

American Journal of Botany, 1979

Diversity assessment of drought tolerant exotic and adapted maize (Zea mays L.) inbred lines with microsatellite markers

Journal of Crop Science and Biotechnology, 2015

Farmers’ Perception and Impact of Rice Yellow Mottle Disease on Rice Yields in Burkina Faso

Agricultural Sciences, 2015

Panel Discussion: Plant Molecular Biology and Plant Breeding

Biotechnology in Plant Science, 1985

Vernon Gracen

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