Search

Increasing agricultural productivity by promoting high-yielding and micronutrient-rich crop varieties has the potential to reduce poverty and malnutrition. However, getting these technologies into the hands of smallholders remains a challenge. This paper presents results from a randomised field experiment that uses rural primary schools as dissemination hubs for improved orange-fleshed sweet potato (OFSP) vines and nutrition information in rural Tanzania and Uganda. Two years after the initial vine distribution, we find that households in treatment villages are 21 percentage points more likely to report growing OFSP and 27 percentage points more likely to correctly state the nutritional benefits of OFSP compared to those in control villages. We also find up to 16 percentage point increase in the likelihood of OFSP consumption by children under 5 years of age in treatment villages compared to that in control villages. Furthermore, we find suggestive evidence that increased knowledge on the nutritional benefits of OFSP mediated up to a third of the total treatment effect on OFSP adoption and consumption. Our findings suggest that rural primary schools can be effective channels for promoting and accelerating the diffusion of micronutrient-rich crop varieties in rural areas. [ABSTRACT FROM AUTHOR]

Potential yield of onion (Allium cepa L.) in semi-arid regions is reduced by abiotic (soil infertility, poor agronomic practices, and unbalanced fertilization) and biotic (use of low yielding varieties, insect pest, and diseases) challenges. Soil infertility causes up to 60% yield loss in onion. This study was undertaken to assess the influence of manure and phosphorus (P2O5) fertilizer levels on growth and bulb development of onion under semi-arid conditions. Manure at 30 or 60 kg/5 m2 or 0.24, 0.48 or 0.62 g/plant for phosphorus and treatments combined at each application rate were used. Application of phosphorus and manure at 0.24 to 0.48 g/plant and 30 kg/5 m2 plot, respectively, improved vegetative and bulb development and weight. A combination of 30 kg/5 plot manure and 0.48 g/plant phosphorus produced an economic benefit based on number and weight of marketable bulbs. Application of 0.24 to 0.31 t∙ha−1 of P2O5, increased number of unmarketable bulbs. 'Red Bombay' performed better than 'Red Mantle.' Individual or combination application of P2O5 at 0.12 to 0.31 t∙ha−1 and organic manure at 60 t∙ha−1 may produce adequate yield, and 'Red Bombay' maybe a better choice than 'Red Mantle' under semi-arid conditions. Application of manure and phosphorus improves vegetative and yield in onion cultivars. Use of 30 kg/5 m2 of manure and a combination of 30 kg/5 m2 and 0.48 g/plant manure and P2O5, respectively, appear to improve yield. [ABSTRACT FROM AUTHOR]

Cassava varieties resistant to cassava mosaic disease (CMD) and cassava brown streak disease (CBSD) are needed for the food and income security of the rural poor in eastern and southern Africa (ESA). The International Institute of Tropical Agriculture led five national cassava breeding programs (Malawi, Mozambique, Kenya, Tanzania and Uganda) in virus-cleaning and exchanging elite cassava germplasm resistant to both diseases. This paper documents the experiences and lessons learned from the process. Thirty-one clones (25 elite, two standard and four national) were submitted by the five breeding programs to the Natural Resources Institute and Kenya Plant Health Inspectorate Services for virus cleaning and indexing. Subsequently, ca 75 in-vitro virus-indexed plantlets per clone were sent to Genetic Technologies International Limited (GTIL), a private tissue culture (TC) lab in Kenya, and micro-propagated to produce ≥1500 plantlets. After fulfilling all the formal procedures of germplasm exchange between countries ≥300 plantlets per clone were sent to each partner country. National check clones susceptible to CMD/CBSD were sent only to their countries of origin. In each country, the in-vitro plantlets were acclimatized under screen house conditions and transferred to clean isolated sites for field multiplication. All the clones were cleaned of the viruses, except Tomo. The cleaning process was slow for F19-NL, NASE1, and Kibandameno and TC micro-propagation at GTIL was less efficient for Pwani, Tajirika, NASE1, and Okhumelela than for the other clones. Difficulties in cleaning recalcitrant clones affected the timeline for establishing the multi-site evaluation trials in target countries. The initiative is the one of the kind to successfully clean and exchange elite germplasm as a joint action to combat CBSD in ESA. Adequate preparation in terms of infrastructure and personnel are critical to successfully receiving and adapting the indexed in-vitro plants as new germplasm. [ABSTRACT FROM AUTHOR]

Sweet potato (Ipomoea batatas[L.] Lam) is a versatile crop globally serving as food, feed and raw material for industries. Designed selection for higher yields and related traits is crucial to identify complementary sweet potato clones for breeding. The objective of this study was to determine phenotypic variation among diverse sweet potato collections with regard to yield, dry matter content (DMC) and sweet potato virus disease (SPVD) resistance and to identify suitable clones for breeding. A total of 144 sweet potato genotypes were evaluated at 2 sites in Tanzania using a 12 × 12 simple lattice design. Data collected included 10 quantitative and 17 qualitative agro-morphological traits and virus reaction. Results indicated differences among genotypes for most traits studied. The mean DMC was 36% with clones Zapallo and Ukerewe exhibiting the lowest and highest values of 29% and 45%, respectively. The mean storage root yield of clones was 5.1 t/ha with genotype Jewel expressing the highest yield of 11.3 t/ha. Genotypes Resisto and Mataya were early flowering at 40 and 50 days, respectively, while Ex-Mwanza and Kandoro did not flower at all. Fifty-eight per cent of the genotypes showed resistant reaction to SPVD, while 31% and 11% were moderately susceptible and susceptible to the disease, respectively. A positive correlation was observed for the number of roots and fresh root yield. Seven clones including Simama, Ukerewe, Mataya, Resisto, 03–03, Ex-Msimbi-1 and Gairo were selected for high storage root yield and related traits or SPVD resistance. The selected genotypes are recommended as potential parents for sweet potato breeding. [ABSTRACT FROM AUTHOR]