Overview of groundnuts research in Uganda: Past, present and future

The Groundnut Department at National Semi-Arid Research Resources Institute (NaSARRI) is mandated to conduct research on groundnuts (Arachis hypogaea L) in Uganda. It undertakes research aimed at cultivar development, maintenance and conservation through germplasm collection, characterization, evaluation, breeding, maintenance and generation of appropriate crop management technologies for sustained production. Most of the varieties traditionally grown by farmers in Uganda are landraces adapted more for survival than yield. Yields from such varieties average 800 kg/ha of dry pods yet yields of 3,000kg/ha have been achieved from on-station plots. Yields per hectare are low, because of a combination of factors such as unreliable rains, mostly non-irrigated cultures, traditional small-scale farming with little mechanization, outbreaks of pest infestations and diseases, the use of low-yielding seed varieties and increased and/or continued cultivation on marginal land. Political instability and the frequently unsupportive oilseed policies have also played their role in low groundnut productivity. Therefore, there is excellent potential for yield improvement. Research efforts have, since the 1920s, endeavored to breed varieties that are high yielding, resistant to major pests and diseases, tolerant to drought, high in oil content and have a short to medium maturity period, as well as to develop appropriate production packages. These efforts have resulted in the release of 14 varieties, the most recent being Igola-1, Serenut 1R, Serenut 2T, Serenut 3R and Serenut 4T. These varieties have helped to alleviate some of the production problems listed above. However, the market and field stability of those varieties, in light of emerging stresses, calls for continuous research while at the same time keeping crop improvement, quality and safety linked to practical applications. Emerging issues like aflatoxin, leafminers and biotechnology need to be addressed and incorporated into the research agenda. Deployment of novel breeding approaches like molecular breeding to complement conventional breeding would increase the efficiency of cultivar development. Additionally, to maintain or increase market share, producers and exporters need to adapt the type of groundnuts being cultivated to consumer requirements.Key words: Arachis, Breeding NaSARRI, Uganda

Human-Like Receptor Specificity Does Not Affect the Neuraminidase-Inhibitor Susceptibility of H5N1 Influenza Viruses

If highly pathogenic H5N1 influenza viruses acquire affinity for human rather than avian respiratory epithelium, will their susceptibility to neuraminidase (NA) inhibitors (the likely first line of defense against an influenza pandemic) change as well? Adequate pandemic preparedness requires that this question be answered. We generated and tested 31 recombinants of A/Vietnam/1203/04 (H5N1) influenza virus carrying single, double, or triple mutations located within or near the receptor binding site in the hemagglutinin (HA) glycoprotein that alter H5 HA binding affinity or specificity. To gain insight into how combinations of HA and NA mutations can affect the sensitivity of H5N1 virus to NA inhibitors, we also rescued viruses carrying the HA changes together with the H274Y NA substitution, which was reported to confer resistance to the NA inhibitor oseltamivir. Twenty viruses were genetically stable. The triple N158S/Q226L/N248D HA mutation (which eliminates a glycosylation site at position 158) caused a switch from avian to human receptor specificity. In cultures of differentiated human airway epithelial (NHBE) cells, which provide an ex vivo model that recapitulates the receptors in the human respiratory tract, none of the HA-mutant recombinants showed reduced susceptibility to antiviral drugs (oseltamivir or zanamivir). This finding was consistent with the results of NA enzyme inhibition assay, which appears to predict influenza virus susceptibility in vivo. Therefore, acquisition of human-like receptor specificity does not affect susceptibility to NA inhibitors. Sequence analysis of the NA gene alone, rather than analysis of both the NA and HA genes, and phenotypic assays in NHBE cells are likely to adequately identify drug-resistant H5N1 variants isolated from humans during an outbreak

Effects of social network factors on information acquisition and adoption of improved groundnut varieties: the case of Uganda and Kenya

Univ Talca, Dept Agr Econ, Talca, Chile. Bravo-Ureta, BE (Bravo-Ureta, Boris E.)Social networks play a significant role in learning and thus in farmers' adoption of new agricultural technologies. This study examined the effects of social network factors on information acquisition and adoption of new seed varieties among groundnut farmers in Uganda and Kenya. The data were generated through face-to-face interviews from a random sample of 461 farmers, 232 in Uganda and 229 in Kenya. To assess these effects two alternative econometric models were used: a seemingly unrelated bivariate probit (SUBP) model and a recursive bivariate probit (RBP) model. The statistical evaluation of the SUBP shows that information acquisition and adoption decisions are interrelated while tests for the RBP do not support this latter model. Therefore, the analysis is based on the results obtained from the SUBP. These results reveal that social network factors, particularly weak ties with external support (e.g., researchers, extension agents, etc.), partially influence information acquisition, but do not influence adoption. In Uganda, external support, gender, farm size, and geographic location have an impact on information acquisition. In Kenya, external support and geographic location also have an impact on information acquisition. With regard to adoption, gender, household size, and geographic location play the most important roles for Ugandan farmers, while in Kenya information from external sources, education, and farm size affect adoption choice. The study provides insight on the importance of external weak ties in groundnut farming, and a need to understand regional differences along gender lines while developing agricultural strategies. This study further illustrates the importance of farmer participation in applied technology research and the impact of social interactions among farmers and external agents

Expression of the Tobacco Mosaic Virus Movement Protein Alters Starch Accumulation in Nicotiana benthamiana

Nicotiana benthamiana plants were transformed with the movement protein (MP) gene of tobacco mosaic virus (TMV), using Agrobacterium-mediated transformation. Plants regenerated from the transformed cells accumulated 30-kDa MP and complemented the activity of TMV MP when infected with chimeric TMVs containing defective MP. These transgenic plants displayed stunting, pale-green leaves, and starch accumulations, indicating that TMV MP altered the carbon partitioning for leaves involved in TMV cell-to-cell movement.ope