Bio

Dr Onyango's biography

Dr. Cecilia Moraa Onyango is Senior Lecturer, Department of Plant Science and Crop Protection, University of Nairobi since 2014. She joined the University of Nairobi in 2001 as an Assistant Lecturer. Dr Onyango earned her PhD (Horticulture) from Wageningen University, the Netherlands in 2010, MSc. Horticulture (2000) and BSc. Agriculture (1996) both from the University of Nairobi.

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(Last updated: June 4, 2018)

Publications

2017

Alsanius, BW, A.H. K, CM O, L. M.  2017.  Produce quality and safety. Rooftop Urban Agriculture. , New York: Springer
Mbogo, NW, Kinama JM, Onyango CM, JN K.  2017.  Effect of inorganic fertilizer and cattle manure on growth and yield of two Kenyan potato varieties. International Journal of Agronomy and Agricultural Research (IJAAR). 10(1):65-72.
Njage, PMK, Sawe CT, Onyango CM, I HABIB, NJAGI EDMUNDNJERU, AERTS MARC, MOLENBERGHS GEERT.  2017.  Microbial Performance of Food Safety Control and Assurance Activities in a Fresh Produce Processing Sector Measured Using a Microbial Assessment Scheme and Statistical Modeling. Journal of Food Protection. 80(1):177–188.
Chimoita, EL, Onyango CM, John W. Kimenju, Gweyi-Onyango JP.  2017.  Agricultural Extension Approaches Influencing Uptake of Improved Sorghum Technologies in Embu County, Kenya. Universal Journal of Agricultural Research . 5(1):45-51.

2016

Ontita, EG, Onyango CM, Onwonga RN, Nyamongo D.  2016.  Indigenous Knowledge on the Uses of African Nightshades (Solanum nigram L.) Species among Three Kenyan Communities. Asian Journal of Agricultural Extension, Economics & Sociology. 14(3):1-8.
Nyagari, E, Onyango CM, Onwong’a RN.  2016.  EFFECTS OF INTERCROPPING ARRANGEMENTS AND FERTILIZER APPLICATION ON GROWTH AND YIELD OF AFRICAN NIGHTSHADE (Solanum nigrum L.) IN KISII COUNTY, KENYA. International Journal of Agriculture and Environmental Research. 2(5):1069-1083.
Onyango, CM, Onwonga RN, Kimenju JW.  2016.  Assessment of Spider Plant (Cleome gynandra L.) Germplasm for Agronomic Traits in Vegetable and Seed Production: A Green House Study. American Journal of Experimental Agriculture. 10(1):1-10.
Onyango, CM, Ontita EG, Onwong’a RN, Desterio N, Gapusi JR.  2016.  Status and Production Practices of Vegetable African Nightshade (Solanum nigrum L.) in Selected Communities of Kenya. American Journal of Experimental Agriculture. 13(3):1-12.

2015

Wangolo, EE, Onyango CM, Gachene CKK, Mong’are PN.  2015.  Effects of Shoot Tip and Flower Removal on Growth and Yield of Spider Plant (Cleome gynandra L.) in Kenya. American Journal of Experimental Agriculture. 8(6):367-376.
Linguya, KS, Moraa OC, Wangai KJ, Chao KD.  2015.  POTENTIAL OF INTERCROPPING FOR MANAGEMENT OF SOME ARTHROPOD AND NEMATODE PESTS OF LEAFY VEGETABLES IN KENYA. Journal of Agricultural Sciences. Vol. 60(3):301-314.
OJ, C, GN K, AK M, CM O, AM M.  2015.  Farmers’ risk perceptions and adaptation to climate change in Lichinga and Sussundenga, Mozambique. African Journal of Agricultural Research. 10(17):1938-1942.

2014

Nictor L. Namoi, Onwonga RN, Karuku GN, Onyango CM, Gathumo VN.  2014.  Influence of Selected Ecological Farming Practices on Soil Moisture Retention and Yield of Sorghum (Sorghum bicolor (L.) Moench) and Cassava (Manihot esculanta Crantz) in Semi-Arid Yatta Sub-County, Kenya. Agricultural Science. 6(9):214-231.
Namoi, NL, Onwonga RN, Onyango CM, Karuku GN, Kathumo VN.  2014.  Assessment of Soil Nutrient Balances in Organic Based Cassava (Manihot esculenta Crantz) and Sorghum (Sorghum bicolor (L.) Moench) Cropping Systems of Yatta Sub-county, Kenya. American Journal of Experimental Agriculture . 4(12):1557-1578.
Samuel, KL, John KW, Dora KC, Cecilia OM.  2014.  Growth and yield response of selected species of African leafy vegetables infested with root knot nematodes (Meloidogyne incognita). Global Journal of Biology, Agriculture and Health Sciences . 3(4):1-6.
Liavoga, BA, Kathumo VM, Onwonga RN, Karuku GN, Onyango CM.  2014.  Assessment of trends in land cover and crop type change over two decades in Yatta sub county,Kenya. International Journal of Agriculture, Forestry and Fisheries. Vol. 2(No. 3):46-52.
Sawe, CT, Onyango CM, Njage PMK.  2014.  Current food safety management systems in fresh produce exporting industry are associated with lower performance due to context riskiness: Case study. Food Control. 40:335-343.

2013

Onyango, CM, Kunyanga CN, Ontita EG, Narla RD, Kimenju JW.  2013.  Current status on production and utilization of spider plant (Cleome gynandra L.) an underutilized leafy vegetable in Kenya. Genetic Resources and Crop Evolution. 60(6)

2012

Onyango, CM, Onwonga RN, Mbuvi JP, Kironchi G.  2012.  Climate Change and Variability: Farmers. Asian Journal of Agriculture and Rural Development. : Asian Economic and Social Society
Onyango, CM, Imungi JK, Shibairo SI.  2012.  Influence of organic and mineral fertilization on germination, leaf nitrogen, nitrate accumulation and yield of vegetable amaranth. Journal of Plant Nutrition. : Taylor & Francis
Onyango, CM, Imungi JK, Onwonga RN.  2012.  Effect of Nitrogen Source, Crop Maturity Stage and Storage Conditions on Phenolics and Oxalate Contents in Vegetable Amaranth (Amaranthus hypochondriacus). Journal of Agricultural Science. : Canadian Center of Science and Education
Onyango, CM, Kahiu EN.  2012.  Analysis of the Molecular Diversity of Kenyan Sorghum Germplasm Using Microsatellites. Journal of Crop Science and Biotechnology. : Korean Society of Crop Science and Springer Abstract

The aim of this study was to estimate the extent of the genetic diversity present in sorghum germplasm grown in Kenya using simple sequence repeat markers. A total of 139 accessions were genotyped using 11 microsatellite markers or simple sequence repeats (SSRs) and the genetic diversity was estimated. The markers showed a wide range of differences in quality index from 0.005 to 0.39. The average Polymorphic Information Content value observed was 0.6241 indicating a high level of diversity. The gene diversity index ranged between 0.2419 and 0.9313 with a mean of 0.6627 per locus. A total of 105 alleles were observed with an average of 10.4 alleles per locus. The average heterozygosity level per locus was low at 0.1717. The variability within accessions among the populations was 74.85% and within individual accessions was 18.67%. The results showed that genetic diversity within Kenyan sorghum germplasm accessions is higher than that between the different populations. It is implied that such genetic diversity can be exploited as such or in hybridization programs to improve sorghum varieties currently grown by subsistence farmers in Kenya.

2011

Onyango, CM;, Harbinson J;, Shibairo SI;, Imungi JK.  2011.  Effect of organic and in organic fertilisers on yield and quality of amaranth in sub-Saharan Africa. Abstract

This study was designed to evaluate the influence of manure and mineral fertilization on yield, Kjeldahl nitrogen (as protein equivalents), Vitamin C and nitrate accumulation in Amaranthus hypochondriacus. The vegetables were produced in field trials, set up in the University of Nairobi, Kenya, during the long rains period between March and May in 2007 and 2008 using diammonium phosphate (DAP; 20, 40 and 60 kg N ha-1) and manure; 40 kg N kg ha-1,) and the yield, Kjeldahl nitrogen (K-N; a proxy for protein content), vitamin C and nitrate levels were measured. The manure treatment produced little increase in productivity though it increased K-N levels. The DAP treatments produced increases in yield, but these saturated at 40 kg N ha -1. The K-N content of the leaves was high, ranging from 2.5 % to just over 4 %, and, broadly, increased with fertiliser application though the variation between the treatments was lower than that for yields. Nitrate levels, however, also increased with DAP fertilisation, resulting in an increase in the nitrate:K-N at high DAP applications, especially in younger plants. There were no clear correlations between ascorbic acid content and K-N. Nonetheless, the plants grown under different fertilisation regimes can be placed into three broad groups; those characterised with low to moderate K-N contents and low to high ascorbic acid contents, moderate to high K-N and low to high ascorbic acid content, and lastly high K-N and low ascorbic contents. Therefore, the growth environment of amaranth, can have a major impact not only on the productivity of the crop but its nutritional value. In this respect the mineral nutrient supply to the crop is of particular importance.
Onyango, CM;, Harbinson J;, Imungi JK;, Kooten O.  2011.  Influence of maturity at harvest, N fertiliser and postharvest storage on dry matter, ascorbic acid and β-carotene contents of vegetable amaranth (Amaranthus hypochondriacus). Int. J. Postharvest Technology and Innovation,. 2(2):180-196. AbstractWebsite

Vegetable amaranth is a leafy vegetable traditionally grown in sub-Saharan Africa and Asia where it is the most consumed traditional vegetable. It is considered to have high nutritional quality, containing relatively large amounts of vitamins A and C. We have assessed the influence of the maturity of the vegetable and soil nutrition on the visual and nutritional quality of amaranth. We found that leaf ascorbic acid content is strongly influenced by both maturity and soil nutrition, with leaves of seven week old matured plants having the highest content. β-carotene increased with increasing amount of soil nitrogen and with increasing plant age. The loss of both visual and nutritional quality during storage was influenced more by maturity at harvest and the temperature of storage than the soil nutrition

2008

MORAA, DRONYANGOCECILIA.  2008.  THE PHYSICO-CHEMICAL CHARACTERISTICS AND SOME NUTRITIONAL VALUES OF VEGETABLE AMARANTH SOLD IN NAIROBI-KENYA. Journal of Ecology of Food and Nutrition. : Onyango, M.C., Shibairo, I.S., Imungi, J.K.and Harbinson, J. Abstract
Twenty one major supermarkets and ten independent green grocers in the city of Nairobi were surveyed for types of vegetable amaranths sold and their post harvest handling. The nutrient composition of the vegetables was also analyzed. In addition, information on three other traditional leafy vegetables (TLVs) namely, Cleome gynandra, Solanum nigrum and Vigna unguiculata was obtained. All the vegetables were sold in bundles of average weight 0.45kg. The edible fraction per bundle averaged 38.9%. Chemical analyses showed that vegetable amaranth had a moisture content of 85.5%, therefore a dry matter content of 14.5%. Expressed on dry matter basis, the mean total ash content was 19.2%, crude protein content 26.1% and the crude fiber content 14.7%. The mean ascorbic acid content was 627mg/100g, zinc content 5.5mg/100g and iron content 18mg/100g. The men nitrate content was 732.5mg/100g, total oxalates 5830mg/100g and soluble oxalates 3650mg/100g, while the lead content averaged 1.03mg/100g. The study concludes that vegetable amaranth has potential as popular vegetable in the diets of Kenyans to significantly contribute to provision of micronutrients, particularly iron and zinc.

2007

MORAA, DRONYANGOCECILIA.  2007.  Postharvest handling and characteristics of fresh-cut traditional vegetables sold in Nairobi, Kenya. 8th African Crop Science Conference, Al - Minia, Egypt. : African Crop Science Society Abstract
Twenty one major supermarkets and ten independent green grocers in the city of Nairobi were surveyed for the types of fresh-cut traditional leafy vegetables (TLVs) sold. Cleome gynandra, Solanum nigrum, Vigna unguiculata, Amarathus spp. and Cucurbita spp were found to be the most common TLVs selling. Amaranthus spp. and Solanum nigrum were selling in all the sales outlets surveyed, while the rest were selling in only a few of the sales outlets. For vending, the vegetables were not afforded any formal packaging; instead the vegetables within each type were tied in bundles of similar average size and displayed in troughs or shelves. The average weight of the bundles ranged between 250g for Cucurbita spp. to 650g for Vigna unguiculata. The mean price per bundle was KSh 14.00. The edible portion per bundle averaged between 34.2% for Vigna unguiculata and 84% for Cucurbita spp. Most of the sales outlets sold proportions ranging between 94% and 97% of the total delivery of the vegetables. The major cause of deterioration of the vegetables during vending was wilting. However, it was indicated that significant losses also occurred through spillage. The study concludes that TLVs are becoming important as commercial crops and as items of diets for Kenyans of all levels. Studies on simple postharvest handling to minimize the losses are however, required.

2001

MORAA, DRONYANGOCECILIA.  2001.  Onyango, M.C. and Silim, S.N. Effect of genotype, storage temperature, Shelling and duration of storage on quality of vegetable pigeonpea. In: Silim, S.N., Mergeai, G., and Kimani, P.M. (eds) 2001.. Status and Potential of pigeonpea in Eastern and Southern Africa: Proceedings of a regional workshop, 12-15 Sep. 2000, Nairobi, Kenya.. : African Crop Science Society Abstract
Twenty one major supermarkets and ten independent green grocers in the city of Nairobi were surveyed for the types of fresh-cut traditional leafy vegetables (TLVs) sold. Cleome gynandra, Solanum nigrum, Vigna unguiculata, Amarathus spp. and Cucurbita spp were found to be the most common TLVs selling. Amaranthus spp. and Solanum nigrum were selling in all the sales outlets surveyed, while the rest were selling in only a few of the sales outlets. For vending, the vegetables were not afforded any formal packaging; instead the vegetables within each type were tied in bundles of similar average size and displayed in troughs or shelves. The average weight of the bundles ranged between 250g for Cucurbita spp. to 650g for Vigna unguiculata. The mean price per bundle was KSh 14.00. The edible portion per bundle averaged between 34.2% for Vigna unguiculata and 84% for Cucurbita spp. Most of the sales outlets sold proportions ranging between 94% and 97% of the total delivery of the vegetables. The major cause of deterioration of the vegetables during vending was wilting. However, it was indicated that significant losses also occurred through spillage. The study concludes that TLVs are becoming important as commercial crops and as items of diets for Kenyans of all levels. Studies on simple postharvest handling to minimize the losses are however, required.

2000

Moraa, OC;, Silim SN;, Mergeai G;, Kimani PM.  2000.  Effect of genotype, storage temperature, Shelling and duration of storage on quality of vegetable pigeonpea..

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