Browsing by Author "Kalule Okello, David"
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Item Groundnut Production Guide for Uganda: Recommended Practices for Farmers(National Agricultural Research Organisation, 2013) Kalule Okello, David; Monyo, Emmanuel; Michael, Deom Carl; Jane, Ininda; Herbert Kefa, OlokaGroundnut (Arachis hypogaea L.) also known as peanut, is cultivated in the semi-arid tropical and sub-tropical regions of nearly 100 countries in six continents between 40˚ N and S of the equator. It is an important legume grown and consumed globally and in particular in sub-Saharan African countries (Okello et al., 2010a). For people in many developing countries, groundnuts are the principal source of digestible protein (25 - 34%), cooking oil (44 - 56%), and vitamins. These qualities make groundnut an important nutritional supplement to mainly cereal diets of maize, millet and sorghum of many Ugandans. In many countries, groundnut cake and haulms (foliage, straw/stems) are used as livestock feed. Groundnut is also a significant source of cash income in developing countries that contributes significantly to livelihoods and food security. As a legume, groundnuts improve soil fertility by fixing nitrogen and thereby increase productivity of other crops in the semi-arid cereal cropping systems. Groundnut requires little input, making it appropriate for cultivation in low input agriculture by smallholding farmers. Groundnuts are grown in most of SSA by smallholder farmers as a subsistence crop under rain-fed conditions. Yields per hectare are generally low compared to those from developed countries like the USA, 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, increased and/or continued cultivation on marginal land, poor adoption of agronomic practices and limited extension services. Insecurity instability and the frequently unsupportive oilseed policies have also played their role in low groundnut productivity. Therefore, there is excellent potential for yield improvement. This production guide seeks to address salient issues in groundnut production in order to maximize groundnut productivity.Item Molecular diagnostics of groundnut rosette disease agents in Uganda: Implications on epidemiology and management of groundnut rosette disease(Journal of plant breeding and crop science, 2017) Kalule Okello, David; Adrogu Ugen, Michael; Tukamuhabwa, Phinehas; Ochwo- Ssemakula, Mildred; Lapaka Odong, Thomas; Adriko, John; Kiconco, Faith; Male, Allan; Deom, Carl MichaelThe objective of this study was to use molecular diagnostic tools to detect the agents of groundnut rosette disease (GRD) to guide in varietal development and disease management. Samples were collected from both GRD infected and healthy plants and sites geo-referenced. RNA extraction, cDNA synthesis, polymerase chain reaction (PCR) amplification, electrophoresis, staining and visualization were performed according to standard procedures. Molecular diagnosis of the samples showed various combinations of the GRD agents, some in isolation and others a combination of two or three agents. This distribution is attributed to dependence on the aphid feeding behaviour and pathogenicity of GRD agents. Chlorotic and green rosette symptoms were observed throughout the sampling sites signifying the presence of satellite RNA (sat-RNA) variants. Some plants showing GRD symptoms tested negative for GRD, whereas some healthy-looking plants tested positive for the GRD complexes pointing to the ineffectiveness of phenotypic screening and the need for a molecular diagnostic tool that detects all three GRD agents both in absence or presence of disease symptoms. The absence of groundnut rosette assistor virus (GRAV) in some symptomatic samples signifies that they are epidemiologically dead end sources since GRV and sat-RNA must be packaged within the GRAV coat protein to be aphid transmissible. Oyado (Cassia obtusifolia) tested positive for all the GRD agents making it a potential alternative host. There is an urgent need for validation of the phenotypic screening with molecular tools in efficient diagnosis of the multi-pathogenic GRD in guiding both plant breeding and pathology work.