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Featured researches published by Daniel Karanja.


Experimental Agriculture | 2016

IMPACT OF NUTRITIONAL PERCEPTIONS OF TRADITIONAL AFRICAN VEGETABLES ON FARM HOUSEHOLD PRODUCTION DECISIONS: A CASE STUDY OF SMALLHOLDERS IN TANZANIA

Victor Afari-Sefa; Srinivasulu Rajendran; R. F. Kessy; Daniel Karanja; R. Musebe; S. Samali; M. Makaranga

Recent years have seen increasing political interest and growing public health awareness and advocacy for diversifying diets into highly nutritious traditional vegetables, fruits and other nutrition-sensitive crops as a more viable approach to mitigate the growing scourge of malnutrition due to unhealthy and imbalanced diets. These foods contribute essential micronutrients, vitamins, antioxidants, and other health-related phytochemicals to staple-based diets and their consumption is crucial for the attainment of several Millennium Development Goals. Despite their nutritional benefits and the high farm gate values per unit of land, the production and marketing of traditional vegetables from Tanzania and other countries in sub-Saharan Africa are constrained by factors such as poor quality seeds, lack of appropriate market information and support systems, and lack of consumer awareness of their nutritional importance. This paper investigates the determinants and pathways for smallholder participation in traditional African vegetable production and identifies entry points for farmers to increase traditional vegetable production by linking nutritional awareness and promotion with potential high value markets. A primary survey of 181 traditional vegetable growers from five regions of Tanzania indicates that perceptions about the nutritional value of traditional African vegetables are a main driver of household production decisions in the sector. The results of this study provide evidence that farmers tend to grow more African traditional vegetables as compared to other crops based on their increased level of perception towards nutritional value of traditional vegetables along with other factors such as their market value, timely availability of quality certified seeds, willingness to invest in labour, required training for women and better access to credits. Farm size negatively affects growing traditional vegetables, implying that on a comparative basis, smallholders tend to grow more traditional vegetables than larger-farm operators. Thus, more attention should be given to reducing production and its associated transaction costs by ensuring timely access to quality certified seeds, ensuring optimal use of inputs and increasing labour productivity, particularly for smallholders.


European Journal of Plant Pathology | 2012

Characterization of isolates that cause black rot of crucifers in East Africa

Joseph M. K. Mulema; Joana G. Vicente; David Pink; Alison C. Jackson; Duncan O. Chacha; Lusike Wasilwa; Zakary M. Kinyua; Daniel Karanja; Eric B. Holub; Paul Hand

A study was conducted in the East African countries of Kenya, Tanzania and Uganda in the months of July and August 2009 with the objectives of assessing the status of black rot and race structure of Xanthomonas campestris pv. campestris in the three countries. Samples infected with black rot were collected from farmers’ fields mainly from Brassica oleracea crops (broccoli, cabbage, cauliflower and kales). A total of 399 farms were surveyed of which 260 were from Kenya, 91 from Tanzania and 48 from Uganda. Following successful isolations, a total of 249 isolates of the causal agent, Xanthomonas campestris pv. campestris were recovered. Pathogenicity of all isolates was confirmed on B. oleracea susceptible cultivars Copenhagen Market F1 and Wirosa F1. Sixty of the 250 isolates were race-typed using a differential set Brassica spp. Only two races, 1 (Kenya and Tanzania) and 4 (Kenya, Tanzania and Uganda) were observed however, another race (5) was observed from one isolate recovered from a B. rapa sample obtained from Tanzania in 2003. Genomic fingerprinting with repetitive-PCR revealed clusters that did not depict significant correlations between isolates and geographical location, isolates and host adaptation or isolates and race. However, it did demonstrate existence of genetic differences within the East African X. campestris pv. campestris population indicating that it is not a similar clonal population of the same genetic background.


Renewable Agriculture and Food Systems | 2017

How promoting consumption of traditional African vegetables affects household nutrition security in Tanzania

Justus Ochieng; Victor Afari-Sefa; Daniel Karanja; Radegunda Kessy; Srinivasulu Rajendran; Silvest Samali

Traditional African vegetables have recently received considerable attention for their contribution to food and nutrition security and opportunities for enhancing smallholder livelihoods. Promoting the production and consumption of traditional vegetables is expected to enhance household nutrition among urban and rural households. The Good Seed Initiative (GSI) program promoted production and consumption of nutrient-dense traditional African vegetables in Arusha region in Tanzania to reduce malnutrition through diet diversification. We estimated the impact of promotion activities on households, women, and childrens dietary diversity. The study used cross-sectional data from 258 and 242 households in intervention and control regions, respectively, and applied matching techniques and inverse probability weighting to control for unobserved heterogeneity and selection bias, which could otherwise bias the outcome estimates. We found that households benefiting from traditional vegetable promotion and demand creation activities had significantly higher dietary diversity of children under 5 yr and women in reproductive age. We found no significant impact of promotion activities on households’ dietary diversity. The policy implication is that scaling up promotional and demand creation activities to encourage consumers to grow and eat traditional African vegetables would be an important element in initiatives to increase dietary diversity, particularly for children under 5 and women in Tanzania.


The International Food and Agribusiness Management Review | 2018

Derived demand for African indigenous vegetable seed: implications for farmer-seed entrepreneurship development

Monica K. Kansiime; Daniel Karanja; Christine Alokit; Justus Ochieng

African indigenous vegetables (AIVs) hold potential to address food security and nutrition in Africa. Their production and consumption remain constrained by lack of quality seed. Efforts to promote commercial seed production lack information about the effective demand of AIV seed. This study estimated derived demand for input seed in central Uganda using trans-log production model. Own-price and cross-price elasticities for production inputs were estimated using marginal approach. Seed demand analysis showed that farmers would utilise seed from market sources of approximately 32 tons per year, against current formal supply of 4.4 tons. Estimated price elasticities showed that purchased seed was less sensitive to its own price, implying less significant effect of price change on the quantity of seed demanded over time. Seed production exhibited higher gross margins and returns to labour day compared to vegetable production, suggesting prospects of profitability and sustainability of farmer-seed enterprises as an alternative source of quality seed for farmers.


Development in Practice | 2018

Changing knowledge and perceptions of African indigenous vegetables: the role of community-based nutritional outreach

Monica K. Kansiime; Justus Ochieng; Radegunda Kessy; Daniel Karanja; Dannie Romney; Victor Afari-Sefa

ABSTRACT African indigenous vegetables (AIVs) have potential to sustainably address malnutrition, a growing problem in sub-Saharan Africa. Their consumption is however, limited by poor perceptions and lack of awareness of nutritional benefits. There is limited evidence of the effectiveness of community-focused information dissemination approaches in influencing participants’ perceptions and uptake of innovations in AIVs to address malnutrition. This article aims to fill this knowledge gap, using a case study focusing on pastoral communities in Monduli district in northern Tanzania. Target communities participated in a community-based nutritional outreach facilitated by the Good Seed Initiative (GSI), held at Monduli district hospital in September 2014. The results provide evidence of the achievements of the GSI intervention, and the effectiveness of alternative information dissemination approaches.


Journal of development and agricultural economics | 2015

Technical efficiency of traditional African vegetable production: A case study of smallholders in Tanzania

Srinivasulu Rajendran; Victor Afari-Sefa; Daniel Karanja; Richard Musebe; Dannie Romney; Magesa A. Makaranga; Silivesta Samali; Radegunda Kessy


Food Security | 2010

The underlying cause of the 2009 sorghum failure in Kongwa district and its implications for Tanzania’s vulnerability to climate change

Sam L. J. Page; Daniel Karanja; Ambonesigwe M. Mbwaga; Elias A. S. Letayo; Lebai T. H. Nsemwa


The International Food and Agribusiness Management Review | 2016

Farmer-Led Seed Enterprise Initiatives to Access Certified Seed for Traditional African Vegetables and its Effect on Incomes in Tanzania

Srinivasulu Rajendran; Victor Afari-Sefa; Daniel Karanja; Richard Musebe; Dannie Romney; Magesa A. Makaranga; Silvest Samali; Radegunda Kessy


Egyptian Journal of Biological Pest Control | 2018

Management of white grubs (Coleoptera: Scarabeidae) with entomopathogenic nematodes in Rwanda

Joelle Kajuga; Athanase Hategekimana; Xun Yan; Bancy Waweru; Hongmei Li; Kebin Li; Jiao Yin; Li Cao; Daniel Karanja; Christine Umulisa; Stefan Toepfer


2016 Fifth International Conference, September 23-26, 2016, Addis Ababa, Ethiopia | 2016

Promoting consumption of traditional African vegetables and its effect on food and nutrition security in Tanzania

Justus Ochieng; Victor Afari-Sefa; Daniel Karanja; Srinivasulu Rajendran; Samali Silvest; Radegunda Kessy

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