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Silas Obukosia

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SHORT BIOGRAPH- SILAS OBUKOSIA PHDJune 2016 until Now-Principal Programme Officer- Principal Program officer with AUDA-NEPAD Regional Officer, Nairobi Kenya and a Coordinator of AUDA-NEPAD Nairobi, Kenya Node. Duties- Coordinate office activities, conducts biosafety capacity building of regulators and policy makers in African Union Members states. May 2015- May 2016- Principal Programme Officer- Operations Management with NEPAD Planning and Coordinating Agency-Africa Biosafety Network of Expertise. May 2008 to May 2015: Director of Regulatory Affairs, Africa Harvest International Biotechnology Foundation for Africa Biofortified Sorghum Program funded by Bill and Melinda Gates Foundation and Warren Buffet Foundation. Later funded by Howard Buffet Foundation. 2002-2008: Agricultural Biotechnology Advisor with United States Agency for International Development (USAID/Kenya. The duties entailed management of USAID/Kenya program in biotechnology that consist of research, public outreach and developing a functional Biosafety Regulatory Framework in Kenya. 1997-2002- Senior Lecturer in the Department of Crop Science, University of Nairobi, October 1997 to September 2002. Taught Biotechnology, Biosafety, Molecular Biology. Education: Ph.D. in Molecular Genetics, Pennsylvania State University (USA) 1988-1992

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Papers by Silas Obukosia

Restriction mapping of Cucurbitae pepo L. chloroplast DNA Pstl 9.8 kb fragment and detection of ORF 2280 transcripts

African Journal of Biotechnology, Jan 31, 2005

Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inve... more Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inverted repeat A (IRA) and on the PstI 12.1 kb fragment in the inverted repeat B (IRB) on the physical map of squash chloroplast DNA. A fine map of the PstI 9.8 kb fragment was developed using SalI, BamHI and EcoRI restriction enzymes.Two transcripts of 1.4and 2.6 kbs of ORF 2280 of squash plastid DNA were detected in fruits but not in the leaves of Early Prolific cultivar using a heterologous PstI 1.2 kb tomato plastid DNA probe internal to ORF 2280.In Bicolor gourd fruits, 1.4 and 2.6 kb transcripts of ORF 2280 weredetected both in the fruits and in leaves.

Restriction mapping of Cucurbitae pepo L. chloroplast DNA Pstl 9.8 kb fragment and detection of ORF 2280 transcripts

African Journal of Biotechnology, Jan 31, 2005

Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inve... more Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inverted repeat A (IRA) and on the PstI 12.1 kb fragment in the inverted repeat B (IRB) on the physical map of squash chloroplast DNA. A fine map of the PstI 9.8 kb fragment was developed using SalI, BamHI and EcoRI restriction enzymes.Two transcripts of 1.4and 2.6 kbs of ORF 2280 of squash plastid DNA were detected in fruits but not in the leaves of Early Prolific cultivar using a heterologous PstI 1.2 kb tomato plastid DNA probe internal to ORF 2280.In Bicolor gourd fruits, 1.4 and 2.6 kb transcripts of ORF 2280 weredetected both in the fruits and in leaves.

Citrus Tissue Culture Project

The molecular genetics of fruit chromoplasts from cucurbita pepo L.: variation in steady-state quantities of RBCL, ESBA, and ORF 2280 transcripts, changes in levels of rubisco large subunit and rubisco activity during fruit development

Biotechnology of Nutritionally Enhanced Food Crops Targeting Malnutrition in Rural Agricultural Populations: The Case Study of Africa Biofortified Sorghum

Science policy reports, 2014

Biofortification of staple foods has great potential in alleviating the rampant micronutrient def... more Biofortification of staple foods has great potential in alleviating the rampant micronutrient deficiency in low income countries, mainly in Africa, through developing staple foods with enhanced minerals and vitamins. The three most important minerals and vitamins of focus include enhanced vitamin A and bioavailable zinc and iron, while folate and iodine deficiencies are met through other approaches including fortification. Currently, on-going research in biotransformation focuses on developing four staples (rice, sorghum, cassava, and bananas) with enhanced pro-vitamin A, zinc, and iron. Of these, Africa biofortified sorghum, cassava, and bananas mainly target African countries. In the Africa Biofortified Sorghum Project, the first priority product to be commercialized will be sorghum with enhanced vitamin A, and the second priority product will be to augment pro-vitamin A with increased bioavailable zinc and iron. The primary target countries of release will be Kenya and Nigeria, representing East Africa, and West Africa Anglophone countries, respectively. Biofortification through genetic transformation complements on-going biofortification efforts through conventional breeding and fortification, especially among those rural farmers/consumers that do not buy commercial fortified foods, or consumers located in arid and semi-arid regions of Africa with little access to vegetables and fruits in the dry seasons.

Effect of Thidiazuron, Naa and Bap on in Vitro Propagation of Alstroemeria Aurantiaca CV. ‘Rosita’ from Shoot Tip Explants

Journal of Agricultural Science and Technology, Oct 24, 2014

Effect of levels and timing of application of gibberellic acid on growth and yield components of common beans

African Crop Science Journal, Aug 17, 2004

In Vitro Embryo Culture of Interspecific Hybrids Between the Kenyan Lines of Phaseolus Vulgaris L. And Phaseolus Acutifolius A. Gray

Acta horticulturae, 1988

Nucellar embryo culture of <i>Citrus sinensis</i> L. and <i>Citrus limon</i> L

African Crop Science Journal, Feb 1, 2000

Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon... more Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon cultivar Rough Lemon produced somatic embryos within 60 days of culture on Murashige and Skoog (MS) basal medium supplemented with 0.4 g l-1 of filter-sterilised casein hydrolysate or 10% coconut water. Embryos that were separated and subcultured in MS media containing casein hydrolysate or coconut water but without hormones, first developed roots within 4 to 8 months and then shoots within 6 to 9 months of in vitro culture. Plantlets were transplanted to soil from 7 to 9 months after initiation. Callus-like tissue consisting of pseudobulbils was observed after 4 to 5 months from the time of initiation. Pseudobulbils developed into visible embryos with multiple cotyledons when subcultured into MS media containing casein hydrolysate or 10% coconut water after 19 to 27 days of in vitro culture. These embryos produced plantlets in which roots developed after 6 to 10 months and shoots formed after 8 to 11 months from the time of initiation. Key Words: Citrus, nucellar embryo culture, somatic embryogenesis (African Crop Science Journal: 2000, 8(2): 109-116)

In vitro ovule culture of Citrus sinensis L

Effects of Genotype andin VitroMedia Composition on Micropropagation of Sugar Cane

East African Agricultural and Forestry Journal, 2001

The use of plant tissue culture for plant regeneration and propagation on large-scale requires a ... more The use of plant tissue culture for plant regeneration and propagation on large-scale requires a quantitative approach to optimised conditions associated with vegetative plant regeneration (Lal and Lal, 1990). Numerous factors affect morphogenesis and proliferation rates in micropropagation systems. These include the media composition (

Elevated vitamin E content improves all- <i>trans</i> β-carotene accumulation and stability in biofortified sorghum

Proceedings of the National Academy of Sciences of the United States of America, Sep 12, 2016

Efficacy of Thidiazuron in In Vitro Propagation of Carnation Shoot Tips: Influence of Dose and Duration of Exposure

African Crop Science Journal, 2003

One of the main challenges facing production of good quality cut flowers is the lack of clean pla... more One of the main challenges facing production of good quality cut flowers is the lack of clean planting material especially among resource poor farmers who resort to multiplying their own propagules with detrimental results. Carnation (Dianthus caryophillus L. cv. Yair) is an important export crop among farmers in Kenya. Carnation production, however, is constrained by lack of clean planting materials. The main objective of this study was to evaluate the potency of thidiazuron (TDZ), a phenyl urea, in evoking morphogenic response invitro compared to combined auxin (NAA) and cytokinin (kinetin) from shoot tip explants of carnations as one possibility of producing en mass clean planting materials. In addition, the study was instituted to determine the optimum concentration and duration of exposure of TDZ in the number, length and general quality of shoots formed. Results from the study indicate that TDZ, at low concentrations of 0.1-1 µM, was just as effective as 0.2 mg-1 L NAA + 0.2 m-1 L kinetin in improving the number, length and quality of shoots regenerated from the explants cultured in vitro. Although multiple shoots were formed from explants cultured on media supplemented with high doses of TDZ (5 µM), they were dwarfed and of a poorer quality. Prolonged exposure of carnation shoot tip explants to high concentrations of TDZ was detrimental to plant regeneration. Sufficient morphogenic response could be achieved by exposing the explants to 1-5 µM TDZ for short durations of 3-10 days with subsequent transfer to MS basal medium devoid of any plant growth regulators.

In Vitro Embryo Culture of Interspecific Hybrids Between the Kenyan Lines of Phaseolus Vulgaris L. And Phaseolus Acutifolius A. Gray

XII African Symposium on Horticultural Crops, 1988

Update of Regulatory Options of New Breeding Techniques and Biosafety Approaches among Selected Countries: A Review

Asian Journal of Biotechnology and Bioresource Technology

A new set of breeding techniques, referred to as New Breeding Techniques developed in the last tw... more A new set of breeding techniques, referred to as New Breeding Techniques developed in the last two decades have potential for enhancing improved productivity in crop and animal breeding globally. These include site directed nucleases based genomic editing procedures-CRISPR and Cas associated proteins, Zinc Finger Nucleases, Meganucleases/Homing Endonucleases and Transcription- Activator Like-Effector Nucleases for genome editing and other technologies including- Oligonucleotide-Directed Mutagenesis, Cisgenesis and intragenesis, RNA-Dependent DNA methylation; Transgrafting, Agroinfiltration, Reverse breeding. There are ongoing global debates on whether the processes of and products emerging from these technologies should be regulated as genetically modified organisms or approved as conventional products. Decisions on whether to regulate as GMOs are based both on understanding of the molecular basis of their development and if the GMO intermediate step was used. For example- cisgenesi...

Molecular characterization of ‘Candidatus Liberibacter ' species/strains causing huanglongbing disease of citrus in Kenya

LH: lower highlands LM: lower midlands MA: monoclonal antibodies UM: upper mislands This study wa... more LH: lower highlands LM: lower midlands MA: monoclonal antibodies UM: upper mislands This study was undertaken to characterize the alpha subgroup of the proteobacteria causing the huanglongbing (HLB) disease of citrus from three different ecological zones of Kenya namely the Lower highlands (LH2, LH3, 1800-1900 m above sea level);

Symptoms, causal agent and distribution of wilt disease of pyrethrum (Chrysanthemum cinerariafolium Vis) in Kenya

Citrus Insect Pests and Farmer Management Practices in Bungoma and Machakos Districts of Kenya

Dr. Dora C. Kilalo - publication

HOMOPTERAN PESTS COMPLEX OF CITRUS (Citrus sinensis) IN SEMI-ARID KENYA

Olubayo F, Kilalo D, Obukosia S, Shibairo S, Kasina M (2011) Homopteran pests complex of citrus (... more Olubayo F, Kilalo D, Obukosia S, Shibairo S, Kasina M (2011) Homopteran pests complex of citrus (Citrus sinensis) in semi-arid Kenya. Int. J. Sustain. Crop Prod. 6(2), 23-28. On farm studies in collaboration with farmers who grow citrus were conducted in upper midlands and lower midlands agroecological zones in Machakos district Kenya. The aim of the study was to understand the factors affecting population fluctuations of homopteran pests attacking citrus in Kenya. White flies (Aleurothrixus flocossus Maskell) and black flies (Aleurocanthus woglumi Ashby) were the most common pests of citrus observed throughout the monitoring. Aphids (Toxoptera citricidus Kirk.) and psyllids (Triozae erytreae Del Guercio) were occasional pests while scales (various) were rare attacking only a few plants within the farms. Time period of sampling had an effect on whitefly, psyllid and blackfly populations. Aphid populations were not affected by the sampling time period. However, there were ecological ...

Restriction mapping of Cucurbitae pepo L. chloroplast DNA Pstl 9.8 kb fragment and detection of ORF 2280 transcripts

African Journal of Biotechnology, Jan 31, 2005

Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inve... more Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inverted repeat A (IRA) and on the PstI 12.1 kb fragment in the inverted repeat B (IRB) on the physical map of squash chloroplast DNA. A fine map of the PstI 9.8 kb fragment was developed using SalI, BamHI and EcoRI restriction enzymes.Two transcripts of 1.4and 2.6 kbs of ORF 2280 of squash plastid DNA were detected in fruits but not in the leaves of Early Prolific cultivar using a heterologous PstI 1.2 kb tomato plastid DNA probe internal to ORF 2280.In Bicolor gourd fruits, 1.4 and 2.6 kb transcripts of ORF 2280 weredetected both in the fruits and in leaves.

Restriction mapping of Cucurbitae pepo L. chloroplast DNA Pstl 9.8 kb fragment and detection of ORF 2280 transcripts

African Journal of Biotechnology, Jan 31, 2005

Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inve... more Using tomato heterologous probe, the ORF 2280 was located on the PstI 9.8 kb fragment in the inverted repeat A (IRA) and on the PstI 12.1 kb fragment in the inverted repeat B (IRB) on the physical map of squash chloroplast DNA. A fine map of the PstI 9.8 kb fragment was developed using SalI, BamHI and EcoRI restriction enzymes.Two transcripts of 1.4and 2.6 kbs of ORF 2280 of squash plastid DNA were detected in fruits but not in the leaves of Early Prolific cultivar using a heterologous PstI 1.2 kb tomato plastid DNA probe internal to ORF 2280.In Bicolor gourd fruits, 1.4 and 2.6 kb transcripts of ORF 2280 weredetected both in the fruits and in leaves.

Citrus Tissue Culture Project

The molecular genetics of fruit chromoplasts from cucurbita pepo L.: variation in steady-state quantities of RBCL, ESBA, and ORF 2280 transcripts, changes in levels of rubisco large subunit and rubisco activity during fruit development

Biotechnology of Nutritionally Enhanced Food Crops Targeting Malnutrition in Rural Agricultural Populations: The Case Study of Africa Biofortified Sorghum

Science policy reports, 2014

Biofortification of staple foods has great potential in alleviating the rampant micronutrient def... more Biofortification of staple foods has great potential in alleviating the rampant micronutrient deficiency in low income countries, mainly in Africa, through developing staple foods with enhanced minerals and vitamins. The three most important minerals and vitamins of focus include enhanced vitamin A and bioavailable zinc and iron, while folate and iodine deficiencies are met through other approaches including fortification. Currently, on-going research in biotransformation focuses on developing four staples (rice, sorghum, cassava, and bananas) with enhanced pro-vitamin A, zinc, and iron. Of these, Africa biofortified sorghum, cassava, and bananas mainly target African countries. In the Africa Biofortified Sorghum Project, the first priority product to be commercialized will be sorghum with enhanced vitamin A, and the second priority product will be to augment pro-vitamin A with increased bioavailable zinc and iron. The primary target countries of release will be Kenya and Nigeria, representing East Africa, and West Africa Anglophone countries, respectively. Biofortification through genetic transformation complements on-going biofortification efforts through conventional breeding and fortification, especially among those rural farmers/consumers that do not buy commercial fortified foods, or consumers located in arid and semi-arid regions of Africa with little access to vegetables and fruits in the dry seasons.

Effect of Thidiazuron, Naa and Bap on in Vitro Propagation of Alstroemeria Aurantiaca CV. ‘Rosita’ from Shoot Tip Explants

Journal of Agricultural Science and Technology, Oct 24, 2014

Effect of levels and timing of application of gibberellic acid on growth and yield components of common beans

African Crop Science Journal, Aug 17, 2004

In Vitro Embryo Culture of Interspecific Hybrids Between the Kenyan Lines of Phaseolus Vulgaris L. And Phaseolus Acutifolius A. Gray

Acta horticulturae, 1988

Nucellar embryo culture of <i>Citrus sinensis</i> L. and <i>Citrus limon</i> L

African Crop Science Journal, Feb 1, 2000

Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon... more Nucellar tissue cultures of polyembryonic Citrus sinensis cultivar Valencia Late and Citrus limon cultivar Rough Lemon produced somatic embryos within 60 days of culture on Murashige and Skoog (MS) basal medium supplemented with 0.4 g l-1 of filter-sterilised casein hydrolysate or 10% coconut water. Embryos that were separated and subcultured in MS media containing casein hydrolysate or coconut water but without hormones, first developed roots within 4 to 8 months and then shoots within 6 to 9 months of in vitro culture. Plantlets were transplanted to soil from 7 to 9 months after initiation. Callus-like tissue consisting of pseudobulbils was observed after 4 to 5 months from the time of initiation. Pseudobulbils developed into visible embryos with multiple cotyledons when subcultured into MS media containing casein hydrolysate or 10% coconut water after 19 to 27 days of in vitro culture. These embryos produced plantlets in which roots developed after 6 to 10 months and shoots formed after 8 to 11 months from the time of initiation. Key Words: Citrus, nucellar embryo culture, somatic embryogenesis (African Crop Science Journal: 2000, 8(2): 109-116)

In vitro ovule culture of Citrus sinensis L

Effects of Genotype andin VitroMedia Composition on Micropropagation of Sugar Cane

East African Agricultural and Forestry Journal, 2001

The use of plant tissue culture for plant regeneration and propagation on large-scale requires a ... more The use of plant tissue culture for plant regeneration and propagation on large-scale requires a quantitative approach to optimised conditions associated with vegetative plant regeneration (Lal and Lal, 1990). Numerous factors affect morphogenesis and proliferation rates in micropropagation systems. These include the media composition (

Elevated vitamin E content improves all- <i>trans</i> β-carotene accumulation and stability in biofortified sorghum

Proceedings of the National Academy of Sciences of the United States of America, Sep 12, 2016

Efficacy of Thidiazuron in In Vitro Propagation of Carnation Shoot Tips: Influence of Dose and Duration of Exposure

African Crop Science Journal, 2003

One of the main challenges facing production of good quality cut flowers is the lack of clean pla... more One of the main challenges facing production of good quality cut flowers is the lack of clean planting material especially among resource poor farmers who resort to multiplying their own propagules with detrimental results. Carnation (Dianthus caryophillus L. cv. Yair) is an important export crop among farmers in Kenya. Carnation production, however, is constrained by lack of clean planting materials. The main objective of this study was to evaluate the potency of thidiazuron (TDZ), a phenyl urea, in evoking morphogenic response invitro compared to combined auxin (NAA) and cytokinin (kinetin) from shoot tip explants of carnations as one possibility of producing en mass clean planting materials. In addition, the study was instituted to determine the optimum concentration and duration of exposure of TDZ in the number, length and general quality of shoots formed. Results from the study indicate that TDZ, at low concentrations of 0.1-1 µM, was just as effective as 0.2 mg-1 L NAA + 0.2 m-1 L kinetin in improving the number, length and quality of shoots regenerated from the explants cultured in vitro. Although multiple shoots were formed from explants cultured on media supplemented with high doses of TDZ (5 µM), they were dwarfed and of a poorer quality. Prolonged exposure of carnation shoot tip explants to high concentrations of TDZ was detrimental to plant regeneration. Sufficient morphogenic response could be achieved by exposing the explants to 1-5 µM TDZ for short durations of 3-10 days with subsequent transfer to MS basal medium devoid of any plant growth regulators.

In Vitro Embryo Culture of Interspecific Hybrids Between the Kenyan Lines of Phaseolus Vulgaris L. And Phaseolus Acutifolius A. Gray

XII African Symposium on Horticultural Crops, 1988

Update of Regulatory Options of New Breeding Techniques and Biosafety Approaches among Selected Countries: A Review

Asian Journal of Biotechnology and Bioresource Technology

A new set of breeding techniques, referred to as New Breeding Techniques developed in the last tw... more A new set of breeding techniques, referred to as New Breeding Techniques developed in the last two decades have potential for enhancing improved productivity in crop and animal breeding globally. These include site directed nucleases based genomic editing procedures-CRISPR and Cas associated proteins, Zinc Finger Nucleases, Meganucleases/Homing Endonucleases and Transcription- Activator Like-Effector Nucleases for genome editing and other technologies including- Oligonucleotide-Directed Mutagenesis, Cisgenesis and intragenesis, RNA-Dependent DNA methylation; Transgrafting, Agroinfiltration, Reverse breeding. There are ongoing global debates on whether the processes of and products emerging from these technologies should be regulated as genetically modified organisms or approved as conventional products. Decisions on whether to regulate as GMOs are based both on understanding of the molecular basis of their development and if the GMO intermediate step was used. For example- cisgenesi...

Molecular characterization of ‘Candidatus Liberibacter ' species/strains causing huanglongbing disease of citrus in Kenya

LH: lower highlands LM: lower midlands MA: monoclonal antibodies UM: upper mislands This study wa... more LH: lower highlands LM: lower midlands MA: monoclonal antibodies UM: upper mislands This study was undertaken to characterize the alpha subgroup of the proteobacteria causing the huanglongbing (HLB) disease of citrus from three different ecological zones of Kenya namely the Lower highlands (LH2, LH3, 1800-1900 m above sea level);

Symptoms, causal agent and distribution of wilt disease of pyrethrum (Chrysanthemum cinerariafolium Vis) in Kenya

Citrus Insect Pests and Farmer Management Practices in Bungoma and Machakos Districts of Kenya

Dr. Dora C. Kilalo - publication

HOMOPTERAN PESTS COMPLEX OF CITRUS (Citrus sinensis) IN SEMI-ARID KENYA

Olubayo F, Kilalo D, Obukosia S, Shibairo S, Kasina M (2011) Homopteran pests complex of citrus (... more Olubayo F, Kilalo D, Obukosia S, Shibairo S, Kasina M (2011) Homopteran pests complex of citrus (Citrus sinensis) in semi-arid Kenya. Int. J. Sustain. Crop Prod. 6(2), 23-28. On farm studies in collaboration with farmers who grow citrus were conducted in upper midlands and lower midlands agroecological zones in Machakos district Kenya. The aim of the study was to understand the factors affecting population fluctuations of homopteran pests attacking citrus in Kenya. White flies (Aleurothrixus flocossus Maskell) and black flies (Aleurocanthus woglumi Ashby) were the most common pests of citrus observed throughout the monitoring. Aphids (Toxoptera citricidus Kirk.) and psyllids (Triozae erytreae Del Guercio) were occasional pests while scales (various) were rare attacking only a few plants within the farms. Time period of sampling had an effect on whitefly, psyllid and blackfly populations. Aphid populations were not affected by the sampling time period. However, there were ecological ...