Uganda Journal of Agricultural Science (UJAS)
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Advances in cassava breeding in Uganda
Get PDFCassava breeding work in Uganda started as far back as 1920 and to date attention has been problemoriented focusing mainly on disease and pest resistance, tuber quality and yield. The approach to cassavabreeding has evolved from breeder led, through a multidisciplinary approach to a more farmer participatoryapproach in order to address farmer needs more effectively. Collaboration and networking have featuredprominently in cassava breeding activities. Between 1990-2000, 12 cassava varieties were released. Futureplans lor cassava improvement activities include targeting specific end uses in order to transform cassavainto a broad based commercial commodity
Control of fishing effort, gears and methods in management of fisheries in lake Victoria and Kyoga
Get PDFNatives around the lakes historically dominated fishing on Lakes Victoria and Kyoga and the fishing gears consisted of locally made basket traps, hooks and seine nets made of papyrus. In view of changes in the fisheries of the two lakes, Frame surveys were conducted on lakes Victoria and Kyoga between 1990 to 2000. Selectivity characteristics of the fishing gears targeting the three major commercial fish species, the Nile perch, Nile tilapia and Mukene on the lakes were studied. Size at first maturity was determined for the three species in both lakes. Historical estimated annual fish catches, effort and catch per unit of effort (CPUE) data were analyzed for Lake Victoria Uganda (CPUE for entire lake) for period 1968 to 1998. Fish catches on Lake Victoria increased from 34,000 metric tones (t) in 1972 to 132,400 t in 1989 alongside an increase in fishing boats from 3000 to 8,000. However, a further increase in boats to 15,418 in 2000 resulted in the decline of the catches from 35 tonnes per boat per year to about 10 t. There was also increased use of longline, handline, beach seines, cast nets, traps, active fishing and mukene nets in different boat categories. Similar trends were observed on Lake Kyoga, where the CPUE had reduced to 14.6 t per boat per year in 1991. Usingvaluesofsizeatfirstmaturity,itwasobservedthattrawlcodends(inL.Victoria),passivegill nets and cast nets mesh sizes below 127mm cropped mostly immature Nile perch and Nile tilapia; boat/ beach seines also harvested mainly immature fish, but mukene nets of 5mm and above harvested mainly mature Mukene. Hooks of size 9 and bigger cropped over 75% mature Nile perch. Basket traps harvested immature Nile tilapia. In view of these trends, it is recommended that fishing effort be reduced to 8000 on Lake Victoria and to below 6500 boats on Lake Kyoga. Destructive fishing gears and practices should be prohibited. Passive fishing using a minimum mesh size of 127mm, drift netting only on Lake Victoria using a minimum gill net mesh size of 152.4 mm, hook fishing with minimum hook of size 9 and mukene nets not below 5mm mesh size operated offshore should be encouraged on both lakes. If trawling and cast nets are to be used (L. Victoria) they should be operated in waters deeper than 20m but the catches are very low and it is difficult to enforce the regulation. Trawling is already prohibited on Lake Victoria
Institutionalising client-oriented participatory agricultural research through regional competitive agricultural technology funds
Get PDFThe strengthening and adoption of farmer participatory research methodologies often pose institutional issues and constraints for the various actors and organisations involved. The Uganda National Agricultural Research Organisation (NARO) is committed to improving the effectiveness oftechnology development and dissemination through increased stakeholder participation in all stages of the research and dissemination process. One of the ways in which NARO is attempting to address institutional constraints to strengthening farmer participatory research is through regional competitive agricultural technology funds, which are being piloted in east and northern Uganda. Application and screening procedures are briefly described, and the applications received in the first two rounds are analysed in terms of partnerships, resources and agricultural themes. The approach appears to be reasonably effective in strengthening stakeholder participation and linkages, and in mobilising skills and resources for participatory research and dissemination. Future challenges include increasing the number of high quality projects submitted by civil society and local government organisations, ensuring meaningful farmer participation, strengthening partnerships and securing sustainable funding
Influence of light quality on the germination characteristics of seeds of selected pioneer, unde.-storey and canopy tree species in Kalinzu forest reserve, Uganda
Get PDFThe effect of light qu11lity and .rnwiog <lqith 011 seed germination of sdtctc<I pi oneer, u11dcrstorey, secondary colonizer andcanopy tree s1>ecies in Ka linzu Fore.st Reser n- was studied. Seeds of d iffrn·nt srecies were sown under incident rad iation,neutral shade, interrupted lc:if slrndc, continuous le:if shade, t.li f feren t coloured ligh ts, d; i r kness, on the soil surrace andin t he soil at a dep th of:tbout l.S cm. There were intcrspccific v:1ria tions in percentage, nites and periods before initiationor germination among the different light treatments. Seeds of the selected pioneer speci es (Mu~·anga leo-arrerae Hauman& Leon) only ge rmin :itet.I under incident light, neutral sha de, interrupted leaf shad e, red ligh t and on the so il s urface.Ni11ely seven percen t of tlw secdi; germinated under incident light nnd 4% under interrupted leaf shade. Seeds of Albizillgummifera J.F. Gmel (seco ndary rn lon i7..(~r), O.\ ) ' fll/.WS .1pecio.111s DC (u ntfl.'rstorcy) and Ft111f11mici africa11t1 Benth. (canopy)germinated under incident r n d i : i t i on. ncutr:il slnule, inte rrupted • ~:if shade, continuous leaf shade and darkness. Seeds o rthe pioneer species germinlltcd only on tlu· so il surface heca use of 1he steep light gradient in the upper soil layers. Seedsof the sub-canopy species germin:i tcd both hclow (with a higher percentage) and on the soil surface
A century of forest management research in Uganda: 1898-1998
Get PDFThe early people of Ugant.la derived their livelihood from natural forests by collecting wild fruits for food, fuelwood fordomestic heating and metal working, wood for building and making canoes for fishing and warfare, herbs and other plantparts for. medicine, and many other social and cultural uses. Subsequently forestry ma.nagement developed into economicactivities to supply both fuelwood and timber for domestic and industrial uses, for export. Forests were also cleared forestablishment of plan ta tion crops such as coffee, sugar cane and tea. Early investigations explored the stocking of rubbertrees and l'ines in the natural forests and ecological, studies which culminated in the publication of the book " IndigenousTrees of Uganda" in 1951. This was followed by the development of silvicultural research involving underplanting ofresidual forest after logging; and the development of polycyclic selection method and a monocyclic shelterwood silviculturalsystem. Plantation forestry research in Uganda wa~ in iti ated to iden tify suitable species for increased aμd reliableproduction of timber and ott1er forest products. This was mainly because the natural forests were incapable of supplyingthe quantities and typ es of timber demanded by the market. Suitable species and provenances for plantation forestry havebeen identifie<l including the techniques for raising and managing them. This paper gives information on fo rest managementresearch in lJganda from 1898-1998. It also gives highlights on future research in both natural and plantation forests
Developments in food science and technology in Uganda:: present situation and the way forward
Get PDFMore than 70% of agricultural GDP in l:lganda comes from food crop production, comprising of bananas, root and tubercrops, grains and legumes and oil seeds. Sugar cnne, livestock products, fisheries, forestry and export crops contribute theremainder. However, before these co mmodities are utilised, they undergo processing in one way or another, a job accomplishedby application of food science and tech no logy principles. Th is pa per gives an overview of the developments in Food Scienceand Technology in Uganda by considering the Food Processing Industry, the factors that have contributed to its currentstatus, its constraints and the way forward. It concludes that if the mentioned constraints are overcome and the suggestedway forward seriously taken, our postharvest losses shall be greatly reduced and food utilisation diversified which are thebasis for food security
Comparative studies on chemical, hot and cold water treatments of banana suckers to control the banana weevil, Cosmopolites sordid us and the effect of paring suckers on banana nematodes in Uganda
Get PDFChemical, bot and cold-water treatments were evaluated for effectiveness in cleaning banana suckers of weevils.Preliminar ily, the effectiveness of paring suckers on removal of weevils and nematodes from banana suckers was validated.Res ults indicated a 36.6%, 67.9% and 96.3% reduction of larvae in corms treated with cold water, hot water and Chlorpyrifos(Dursban) respectively. Use ofDursban at a rate of 1.5 cc in a litre of water and soaking for one hour was recommended asthe best of the three meth ods for cleaning banana suckers. A test carried out to establish the dec:lining rate of efficiencyover successive use of the same solution indicated that the solution does not loose potency, hence can be re-used until thevolume cannot subm·erge suckers any more. With regard to paring alone, there was a 95% reduction of weevil eggs in paredsuckers. The number of larvae recorded from unpared suckers was significantly higher than that recovered from paredsuckers. No nematodes were recovered from pared suckers while both R. similis and H. multicinctus nematodes wererecovered in high numbers from unpared suckers
Socio-economic importance, structure and indigenous management of woody perennials in the home gardens of Mpigi District, Uganda
Get PDFHomegardens are a rorm of agroforestry in which multipurpose woody perennials are grown together with agriculturalcrops and ljvestock is kept on the compounds of individual homes. A study was carried out in Nangabo and Kira sub·counties ofMpigi district to assess the species composition, diversity, structure, socio-economic importance and indigenousmanagement of woody perennials grown in the homegardens. Data were collected from 150 farmers using a semi-structuredquestionnaire and on-farm survey. It was found that more than 70% of the farmers planted or spar-ed woody perennials intheir homegardens and depended on them for nutrition and income. Farmers who practiced homegarden agroforestryowned land under the mailo or free hold land tenure system and the size of land holding varied from 0.1 to 4.2 ha perindividual. Eighty three species of woody perennials were recorded in the bomegardens a nd these were mainly trees and. shrubs grown for provision of fruits, timber, building poles, craft materials, fibres, medicines, firewood, fodder and shade.The plants were grown for both subs istence and cash. The indigenous management practices of the homegardens incl udeduse or wood ash to control agricultural crop and tree pests, pruning and pollarding of trees and shrubs to stimulate·flowering, increase fruit yield and reduce the effect of shading on the agricultural crops, and improvement of soil fertilityby incorporating animal waste and crop residues into the soil
Effects of genotype x bradyrhizobium inoculation or x fertilizer n interactions on genetic gains while selecting in soybean
Get PDFIntroduction of soybe.an (Glycine 1n/l.X (L.) Merr.) to environments where it was not previously produced sometimes occurs without successful introduction of the symbiont, Bradyrf1izobiumjapo11icum (Kirchner) Buchanan. Plant breeders working in such environments need to kno\v whether relative performance of soybean genotypes is affected by the presence or absence of B. japonicum. Tbe primary objective of these studies was to assess genotype x inoculation interactions and expected genetic gains for a soybean population grown with and without inoculation on a soil free of B. japonicum. A second objective was to determine whether the response of soybean genotypes to N depend on the source of N (fertilizer or symbiotic fixation). A set of 52 random lines from a broad-based reference population was evaluated for 2 years with and without B.japonicum inoculation in a split-plot design. Inoculation increased protein content and lodging and decreased oil content. Genotype x inoculation interaction was significant only for protein and oil content in one year. Expected genetic gains were similar with and without inoculation. A second set of 12 genotypes was evaluated for 2 years in ll similar design but with N fertilizer applied as a third N treatment. There were no significant differences among N treatments for any trait. Genotype x inoculation interaction occurred for yield, but not for other traits. Genotype x inoculation interaction for seed yield and composition may occur in some environments but is not a major constraint to genetic gain
Studies on the efficacy of some biorational insecticides against the banana weevil cosmopolites sordidus (Germar) (Coleoptera: Curculionidae)
Get PDFBiorat!onal insecticides obtained from tobacco, ash , urine, pepper and a concoction (mixture) were tested for their effecton adult weevil mortality, repellence and oviposition. Weevil oviposition on corms treated with tobacco, urine and theconcoction was significantly reduced corn pared to oviposition on those treated with ash and pepper and on control corms.Similarly, the mean number of weevils settling on corms treated with the concoction compared to controls was statisticallydifferent for all the periods of the study. The mean number of weevils settling on corms treated with concoctions stored forfour weeks was significantly lower than to those settling on corms lreatcd with concoctions used either immediately orstored for one to two weeks. The concoction showed limited residual activity