Theses and Dissertations Collection

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Screening farmers’ saved rice seed for discolouration and incidence of seed-borne pathogens
(Sokoine University of Agriculture, 2009) Mwipopo, Nuru Grace Eliezer
A study was conducted to screen for seed-borne pathogens causing discolouration in farmers’ saved rice seeds produced in Shinyanga, Mbeya and Morogoro regions in Tanzania. A total of 37 seed samples were tested for the presence of seed-borne pathogens. The blotter method was used to detect fungal pathogens which were identified based on growth habit and morphological characteristics of the fruiting bodies and spores/conidia. The slide cassette holder method was used to detect bacterial pathogens. The isolated bacteria were characterized based on physiological and biochemical tests, hypersensitive reaction and pathogenicity tests. The data were analyzed using MSTAT-C Computer package and mean separation rest using Duncan’s Multiple Range Test at P < 0.05. The identified seed-borne fungal pathogens associated with seed discolouration were Fusarium moniliforme, Phoma sp., Bipolaris oryzae and Altemaria padwickii. All farmers’ saved rice seed samples tested were infected. The highest seed infection was caused by Fusarium moniliforme (16.75%), (26.0%), (13.5%), Bipolaris oryzae (2.0%), (0.5%), (17.25%), Phoma sp. (5.0%), (2.25%), (2.25%) for samples from Shinyanga, Mbeya and Morogoro, respectively. The lowest seed infection was caused by Alternaria padwickii (0.25%), (0.75%) for samples from Shinyanga and Mbeya, respectively. Seed- borne bacterial pathogens causing grain discolouration were identified. The highest seed infection with Acidovorax avenae subsp. avenae was from Shinyanga region, Pseudomonas syringae subsp. syringae from Morogoro region and Psudomonas fuscovaginae infection from samples collected in Morogoro and Mbeya regions. Rice seed from Shinyanga region had high seed infection followed by Morogoro. The results stress the need to encourage farmers to use certified seed which are clean and healthy for planting rather than using their owned saved seeds.
Maize yield losses attributed to the stemborer; Chilo partellus (swinhoe) (lepidoptera: crambidae), in the Eastern agro-ecological Zone of Tanzania
(Sokoine University of Agriculture, 2005) Mgoo, Victor Hango
Lepidopteran stem borers are generally considered the major biotic constraint to increased maize production in Tanzania and elsewhere in Africa. The exotic stem borer, C. partellus, is by far the most important species causing serious damage to maize and sorghum in the eastern zone of Tanzania. The effect of four nitrogen rates (0, 50, 75 and 100 kg Nha'1) on stem borer damage, growth and yield loss of maize was assessed in two seasons in two locations Kibaha and Morogoro. The results show that nitrogen had a positive effect on growth variables, mainly stem diameter, plant height and yield, and negative effect on stem borer damage and stem tunneling. At Kibaha the percentage yield loss due to natural stem borer infestation decreased with increasing nitrogen application from 52.75 % to 19.38 % in the 0 kg Nha‘’and 100 kg Nha’’rates, respectively. There was no stem borer infestation at Morogoro during the first season. During the second season, yield loss decreased from 27.09 % in the 0 kg Nha’1 to 14.84 % in the 100 kg Nha’1 rates at Kibaha, and from 13.19 % to 0.40 % in 0, and 100 kg Nha rates, respectively, at Morogoro. During the second season of 2003, maize fields were surveyed at the vegetative growth phase to asses stem borers abundance and distribution and at harvest for stem borer damage and yield loss. At vegetative stage, C. partellus was the dominant stem borer accounting . for 98.58 %, while S. calamistis accounted for 1.42 % of the population. During harvesting time, there were more S. calamistis (64 %) than C. partellus (36 %). Results from on-farm surveys showed that stem borer tunneling rec'-jced grain yield of infested plants by 10.14 %. A 16.63 % yield loss was found in plants with more than 15 cm tunnels. Stem diameter, plant height, and stem tunneling were found to be the key variables affecting maize grain yield.
Population structure of pyricularia grisea and reaction of rice cultivars in the Southern Highlands of Tanzania
(Sokoine University of Agriculture, 2014) Maganga, Reinfrid Martin
The study was designed to investigate the diversity of Pyricularia grisea (Coke) Sacc, population structure and reaction of rice cultivars in Southern highlands of Tanzania. Screen house experiments and a field trapping nursery were used to determine prevalent pathogenic races, effective host resistant genes and reaction of rice cultivars against identified pathogenic races. A total of six pathogenic races Ull-i2-kl41-zl3-tal03, U51-i4-kl00-zl 3-tal 03, U11-i4-k041-zl 1-tai03, Ull-i5- k000-z03-ta000, U11-iO-kl01-zl3-tal00 and U11 -il-k!20-zl l-tal02 were identified on the basis of the infection type of LIJIANGX1NTUAN HEIGU (LTH) monogenic lines. Pathogenic race U1 l-i2-k 141-zl3-tal03 was the most virulent strain infecting 44.4 % of the tested varieties, followed by U51-i4-kl00-zl3-tal03; Ull-i4-k041- zll-tal03; U1 l-il-kl20-zl I-tal02; U1 l-i0-kl01-zl3-tal00 and U1 l-i5-kOOO-zO3- taOOO infecting 40.7, 37, 37, 33.3 and 14.8 % of the tested varieties, respectively. Host resistance genes PH2, Piz-t, Pill, Pik-rn, Pi 12, Pia, and Pik-p were found effective against the available pathogen races. All local varieties tested were susceptible to all races identified differing only on the levels of susceptibility. Uyole inbred lines (UR 319 and UR 400) were susceptible to all races except race U1 1 -i5- kOOO-zO3-taOOO and race U1 l-i4-k041-zl1-tai 03. The races identified provide an insight of blast population diversity prevalent in Southern highlands that should be considered when breeding for blast resistance. Effective resistant genes identified can be pyramided to Uyole inbred lines and in commonly grown local susceptible rice varieties to improve blast resistant against prevalent races in Southern highlands.
Efficacy of pesticides used on cotton in the Western cotton growing areas of Tanzania
(Sokoine University of Agriculture, 2016) Kabissa, Jeremiah Joe
omplaints against the ineffectiveness of pesticides currently distributed by the Tanzania Cotton Board (TCB) and private dealers in the Western Cotton Growing Areas (WCGA) have persisted for nearly a decade which has rendered some famers abandoning the crop. Technically, the reasons for the low efficacy could be associated with insecticides or poor application techniques. A series of studies were conducted between September 2014 and September, 2015 in the WCGA to document the commonly used pesticides on cotton, examine their authenticity with reference to the registrar’s article and evaluate their effectiveness. Documentation of the commonly used insecticides, accessibility and perceived efficacy were studied through a survey conducted using structured questionnaires in five districts in Mwanza and Simiyu Regions. A total of 175 respondents were interviewed. Authenticity of the commonly used pesticides was examined through sampling among the commonly used pesticides, obtaining small volumes in screw-capped bottles, re-packaging and labelling by numbers to disguise the identity, after which they were sent to the Tropical Pesticide Research Institute (TPRI) laboratories for determination of active ingredients. The effectiveness of the commonly used pesticides was determined through a field experiment set at Ukiriguru Agricultural Research Institute. Cotton insect pests against which the pesticides were tested included; Helicoverpa armigera (Hubner), Aphis gossypii (Glover), Pectinophora gossypiella •(Sound), Dysdercus sp (Herrich- Schaeffer) and Earias sp (Walker/Boisduval). The results indicated that most of the approved and few of unapproved insecticides are used in controlling cotton pests in the WCGA. About 70% of insecticides used by farmers in all five Districts surveyed were supplied through CDTF and the remaining 30% were sourced from private agro-shops and open markets. About 40% of the insecticides sold in agro-shops and local market centres had expired but cotton farmers being unawareiii purchased them for use. About, 85% of agro-shop owners employed unskilled shopkeepers to sell pesticides. The confirmatory test at TPRI laboratories proved the collected insecticides to conform to the registrar’s records in terms of contents and active ingredients. The field tests showed that all insecticides were effective against target insect pests provided the proper dosage was applied at the right time and appropriate pests threshold. Pyrethyroids such as lambdacyhalothrin and cypermethrin when used in combination with organophosphates controlled both endocarpic and exocarpic boll worms and other insect pests very effectively but when lambdacyhalothrin was used singly, the effectiveness was compromised particularly on aphids. Likewise the endocarpic and exocarpic boll worms could not be effectively controlled using cypermethrin alone. The findings from this study resolved the long-standing doubt on efficacy of insecticides distributed to cotton growers through the CDTF. Ineffectiveness reported by farmers are mostly caused by use of inadequate amounts of insecticides (low dosages), mixing insecticides with poor quality waler (dirty water) and poor coverage of the crop canopy during spray. Wrong timing of the day to first spray and poor knowledge of pest threshold also contribute to the limited efficacy of the insecticides in small farmers’ setting. Therefore, the Tanzania cotton sector should take concrete steps to educate growers on proper use of insecticides and avoid the risks of insect pests developing resistance to the used insecticides particularly the Pyrethroids.
The effect of extracts of neem seed on survival and infestation of thrips tabaci on onions
(Sokoine University of Agriculture, 2003) Haule, John Bosco
Field and laboratory studies were conducted at Madiira Research Farm, Arusha to investigate the effectiveness of extracts of neem seeds for management of onion thrips, Thrips tabaci on onions. The efficacy and performance of extracts from N eem seeds, Azadirachta indica was compared with that of Fenitrothion, a commonly used standard insecticide. Neem extracts at concentrations of 0.8% and 1.0% AZ gave good protection against T. tabaci under field condition. A significant decline in population density (P = 0.05) o f o nion t hrips w as o bserved a mong t reatments. F ewer t hrips 1 arvae a nd adults were recorded on treated plants than on control. However, the effectiveness and performance of extracts of neem seed varied with concentration and method of application. Alcohol extracts (0.8%) and aqueous extracts (1.0%) were more effective in lowering the number of T. tabaci. These levels of concentration compared favourably with fenitrothion. Significant differences (P=0.05) in onion yields were generally observed among treatments. Onions treated with extracts of neem seed gave higher yield than the control. The yields were not significantly different from fenitrothion treated crop. Neem seed extracts, even at the low concentration of 0.4 and 0.5%, resulted into significant mortality and ovipositional deterrence of thrips, but were less effective as repellents. Mortality and repellence increased with time and concentrations. At concentrations of 0.4 and 0.5% more thrips were found dead and strayed off from treated leaves. No mortality and repellence occurred in the control leaves. Onion leaves treated with the standard insecticide, fenitrothion, resulted to high death and repellence of thrips at 24 and 48 hours post treatment. The use of neem extracts proved to be effective in providing good protection of onions against T. tabaci. Neem seed extracts have shown good potential for management of onion thrips on onions due to low cost, effectiveness, safety, availability and their easiness to prepare and use.
Investigation of seed-borne fungi and germination of sorghum seed using different substrates
(Sokoine University of Agriculture, 2013) Gaspar, Clement
The study was conducted to determine associated with stored sorghum seeds {Sorghum bicolor} and to identify the suitable and cost effective substrate for conducting sorghum germination tests. Sorghum seed samples used in this study were collected from September to October 2012 from three agro- ecological zones of Tanzania (Lake, Central and Eastern). Laboratory experiments were conducted at TOSCI and Sokoine University of Agriculture Plant Pathology Laboratories from October 2012 to December 2013. Five seed-bome fungal species were detected and identified: Fusarium moniliforme, Bipolaris sorghicola, Curvularia lunata, Colletotrichum graminicola and Phoma sorghina. Other fungi detected were Aspergillus spp., Penicillium spp., Claviceps spp. and Rhizopus spp. The five tested substrates tested for sorghum seed germination were cotton cloth single layer, cotton cloth double layer. The ISTA recommended germination paper was included as control. Sorghum seed germination recorded were 82.45 %, 82.43 %, 82.35 %, 82.07 % and 82.03 % for cotton cloth double layer, ISTA paper, cotton cloth single layer, reused cotton cloth double layer and re-used cotton cloth single layer substrates, respectively. There was no significant difference (P<0.01) in all treatments. Therefore, both single and double cotton cloth substrates have the same efficiency in conducting laboratory sorghum seed germination test. The results from this study showed significant differences (P<0.01) in incidence of seed-bome fungal infection from Kwimba, Chamwino and Kilosa with incidences of 10.5 %, 30.5 % and 50.5 %, respectively.
Assessment of the relative importance of tomato (lycopersicon esculentum mill) pests in Morogoro Tanzania
(Sokoine University of Agriculture, 2008) Bulali, Julita E. M.
A study was conducted to investigate tomato pests of relative importance in farmers’ fields and the effects of management techniques on pests and yields. Biological monitoring of tomato pests was conducted in Morogoro region, at Kipera and Mlali villages tomato growers’ fields in Mvomero district from August to November 2006 and on-station field experiment at Sokoine University of Agriculture Horticulture unit during October 2006 to February 2007. Randomized complete block design (RCBD) was used in farmers’ fields. The treatments were tomato management practices by farmers while five sampling areas were replications. At On-station field experiment, RCBD in spilt plot with five replications was used. Two determinate tomato varieties (CALJ and Tanya) were main factors and seven tomato management techniques including fertilizer, mulching, grower standard, IPM, check, intercrop with cabbage and spider plants, respectively, formed the sub factors. Leaf miner, septoria leaf spot and nutsedges were ranked as major pests for tomato production in the two villages. Farmers’ fields survey indicated that, 70% of farmers practiced monocropping and 80% depended on purchased seeds. On agrochemical use, farmers applied fungicides and insecticides 5-8 times per season. Among management techniques, mulching and IPM were effective in suppressing sedges population by 98.9% and 99.6%, respectively. The study also showed significantly reduced insect pest populations in Grower standard and IPM. Furthermore, the study indicated that, spider plants attracted more of both insect pests and beneficial insects compared to tomato monocrop. The study showed that mulching resulted in five times cumulative yields compared to control. Highest number of damaged fruits was due to sunny scotch in farmers’ fields and mulching treatments. The study suggests that mulching and IPM could be used to suppress tomato pests and spider plants could be incorporated
Current status of sunflower leaf blight caused by alternaria helianthi in Iramba and Handeni Dstricts in Tanzania
(Sokoine University of Agriculture, 2013) Chirimi, Stella Gamaliel
Surveys were conducted to investigate the incidence and severity of Alternaria blight disease caused by Alternaria helianthi in Iramba and Handeni districts. A total of 30 seed samples collected from farmers were tested for infection by A. helianthi and other fungi using the Blotter method. Identification of fungi was based on morphological characteristics observed under the stereo and compound microscopes and confirmed by pathogenicity tests done in the screen house. Screen house and field data were analyzed using SAS 2004 and SPSS computer package and mean separation was done by Duncan Multiple Range Test at < 0.05. Results showed that sunflower seed samples were infected by A. alternata (47.75 %), F. palidoroseuni (16.25 %), F. moniliforme (12.0 %), M. phaseolina (3.75 %), and A. helianthi (3.75 %). Seed infection by A. helianthi was lower than that of other seed-bome pathogens. However, it was associated with the highest disease incidence (22.7 %) compared to A. alternata (13.5 %) and Fusarium species (1.5 %), under field conditions. Such results implied that low seed infection by A. helianthi can result into high disease incidences under field conditions. The results also showed that A. helianthi can be categorized into two groups based on their morphology. The first group had large radial growth, gray mycelia colour and smooth margin and the second group had grayish black appearance and irregular margins on VS agar medium, implying variations of A. helianthi. The results also showed that most of the fanners (70 %) in the study areas were unaware of the disease and 76.7 % of fanners did not apply any control measure for Alternaria blight disease. Future studies should therefore, focus on factors that influence high level of disease incidences and severity in the field compared to low level of seed infection. Further studies on the genetic variation between the two groups of A. helianthi are also needed. Training of the farmers on identification of ' Alternaria blight disease is of importance for early disease management.
Transmission of bean common mosaic virus (BCMV) between common beans (phaseolus vulgaris l.) and weld alternate hosts by aphids
(Sokoine University of Agriculture, 1996) Yoere, Charles Ragovura
Recent advances in the epidemiology ofbean common mosaic virus (BCMV) suggest that some wild leguminous plants are hosts of this virus. Aphid vectors may spread BCMV to susceptible host plants including the common bean, Phaseolus vulgaris L. This study was conducted in 1995 in order to determine the natural occurrence of aphids on wild leguminous plants, to obtain virus isolates from virus-infected leguminous plants, and to collect seeds of wild legumes for propagation and testing of their ability to cany the virus. Virus isolates were mechanically inoculated onto P. vulgaris in the glasshouse in order to determine their transmissibility. Isolates which caused characteristic BCMV synq)toms and confirmed to be BCMV by serology were used in aphid transmission studies. Aphis craccivora and A. fabae were reared on caged P. vulgaris and used as BCMV vectors. Aphid-inoculated plants were observed for symptom development at weekly intervals for four weeks. Natural occurrence of aphids on wild legumes during the February/ Marcperiod was rare. No wild leguminous plant was found to be naturally infected with BCMV. Five BCMV isolates obtained from P. vulgaris were readily aphid-transmitted between P・ vulgaris plants. Aphid transmission of these isolates from P. vulgaris onto healthy wild legiuninous test plants neither caused systemic infection nor subsequent development of virus synq)toins on the test plants. However, isolate 105 was detected in two of the wild leguminous ^ecies (Crotalaria incana and Tephrosia nana) by PAS-ELISA after aphid-inoculation from infected P. vulgaris. Back-inoculation from these two wild legumes onto healthy P. vulgaris test plants was unsuccessful It was concluded from this study that although some wild legumes could harbour BCMV, the ease with Which the virus could be transmissible from such reservoirs by aphid vectors to healthy susceptible hosts was questionable and needs to be more precisely determined.
Damage, losses and dynamics of infestation of maize by sitophilus zeamais and prostephanus truncates in single and mixed populations
(Sokoine University of Agriculture, 2008) Swila, Ntuli Tikusekela
This study was carried out at the Pest Management Center of Sokoine University of Agriculture (SPMC) to establish the dynamics of infestation and crop damage by weevil Sitophilus zeamais (Motsch.) and the Larger Grain Borer, Postephanus truncatus (Hom) in single and mixed populations infesting stored maize. The study also aimed at establishing the population characteristics of the two pests in storage structures. Maize variety Staha was used for the study. Crop damage was investigated by determining the following parameters: number of damaged grains, number of undamaged grains, weight losses due to infestation by S. zeamais and P. truncatus. Population dynamics of S', zeamais and P. truncatus in single and mixed populations was investigated by determining the number of emerged adults. Significant (P<0.05) increases in damage were observed after four months of storage. S. zeamais was found to cause more damage in cribs compared to P. truncatus, where in laboratory experiment P. truncatus caused higher damage. 5. zeamais increased faster in numbers than P. truncatus in single species population. Natural infestation was not high until after seven months of storage for P. truncatus where as S. zeamais, increased in numbers after three months of storage. Cross infestation between stores appears to be important in crop loss and damage and therefore, dis-infested maize is likely to develop new infestation within six to seven months of storage. It is concluded that evolution of crop damage and crop losses due to the two pests is very dynamic. Therefore management of the two pests should consider the timing of the control activities to be crucial to reducing damage and losses.lt is recommended that control actions to reduce the damage and losses due to P. truncatus and S. zeamais should be undertaken not later than three to four months after maize storage.
Levels of angular leaf spot (ALS) resistance in common bean (phaseolus vulgaris. l) populations developed for als resistance
(Sokoine University of Agriculture, 2008) Mndolwa, Eninka John
Angular leaf spot (ALS) incited by Phaeoisariopsis griseola is wide spread in all bean growing areas in Tanzania. It is of great concern in wet bean growing areas of the country, yet little information is available in Tanzania on cultivars resistant to the disease. The objective of this work was to incorporate angular leaf spot (ALS) resistance in adapted common bean lines through backcrossing procedure, determine inheritance of ALS in the crosses and screen advanced backcross lines for ALS resistance. Backcrossing was done in the screen house at SUA where G5686 x C/wonder, Amendoim x Rojo and Mexico54 x Soya were crossed to their respective parents. The backcrossed lines obtained together with the advanced bean lines from Prosser USDA-ARS Washington were evaluated for resistance to ALS. Completely randomized design (CRD) was used in screen house and Randomized Completely Block Design (RCBD) was used for field trials. For F2, F3, BC m and BC1.2 there was no randomization nor replication as this has no effect in early generations of bean improvement. For the advanced lines there were three replications in each of the two different locations i.e. SUA-Morogoro and Madira, Arusha. An appreciable amount of genetic variation (P < 0.05) for ALS resistance, pods per plant and seed yield was observed. The following advanced lines were found resistant to ALS in both locations PSO4・336Ab・7, PSO4-126Aa-8, PSO4-335B-1, PSO4-139Ba-l, PSO4- 139Bb-5, PSO4-139Bb-l, PSO4-106Ba-2, PSO4-139Bb-4, PSO4-126Ab-8, PSO4- 139Ba-7, PSO4-139Ab-10 and PSO4-126Aa-6. Both lines showed intermediate or resistant reaction to ALS disease, moreover, some of these did not develop any disease symptoms and thus could be immune to the disease or have escaped the disease. Significant and positive correlation between number of pods per plant and yield was observed in advanced lines where r = 0.751, (P < 0.001) fbr Morogoro trial where r = 0.509 and (P < 0.001) for Arusha trial. Heritability estimates were low 0.190 to medium 0.228 for disease resistance and moderate 0.30 to high 0.73 fbr number of pods per plant. It is recommended that further studies be conducted among the lines evaluated and the best performing lines to be selected then advanced and later be evaluated for other characteristics such as size, cooking time and protein concentration.
Evaluation of common bean (phaseolus vulgaris l.) genotypes under drought stress conditions in the Southern Highlands of Tanzania
(Sokoine University of Agriculture, 2017) Mazengo, Karantin David
A study was conducted to evaluate common bean (Phaseolus vulgaris L.) genotypes for drought tolerance in Southern Highlands of Tanzania. Eighteen genotypes were selected for conducting experiments in the field and screen house,on June, 2015. The field experiment was conducted at Inyala Agricultural Training Institute while the screen house experiment was laid out at Uyole Agricultural Research Institute. Experiments were laid out in a 3x18 split plot arranged in randomized complete block design (RCBD) with 3 replications. Results for seed yield under stress and non-stress condition were used to calculate yield indices which were used to predict tolerant bean genotypes. Results showed significant differences (p < 0.05) of yields across genotypes and water treatments. Genotypes BFS60, KG 104-72 and SERI6 yielded highest under stress at flowering while genotype KG4-30, RCB266, KG25-21 and KG 104-72 yielded highest under stress at mid pod filling. Selection indices, such as yield index (YI) selected BFS60 as most tolerant genotype followed by KG 104-72 and SER 16 while Stress tolerance index (STI) selected SER 16 followed by BFS60 and KG 104-72; Stress susceptibility percent index (SSPI) selected RCB266 followed by SER 16, 41-EX-VAM and SER83 as most tolerant genotypes. Genotypes SER 16, BFS60, KG 104-72 and CZ109-22 were found as most tolerant genotypes when the means of rankings of yield indices ranked. Correlation analysis showed that yields under non stress condition (Yp) were significant and positively correlated with YI, STI and SSPI, while yields under stressed condition (Ys) were significant and positively correlated with YI and STI. On the other hand, yields under (Ys) were not significant and negatively correlated with SSPI. Genotypes (SER 16, BFS60 and KG 104-72) are among of the most tolerant to drought conditions, therefore, can be used as parental materials in breeding for drought tolerance.
History and etiology of the lethal disease of coconut palm ( cocos nucifera l. ) in Tanzania
(Sokoine University of Agriculture, 1987) Kaiza, Dominick Alfred
In the Bagamoyo District,large coconut plantations were established as early as 1870 and the industry received a further impulse from German settlers in the 1930's. The first report on the occurrence of the lethal disease was in 1911. fit present the incidence of the disease is low. Coconut palms were planted in the Klsarawe and Rufiji Districts during three main periods. The first during the Arab rule mainly between 1070 and 1888, the second during the German administration (1891 - 1914 ) and the third and most important after the first World Wer. Although the lethal disease occurred probably as early as 1890, it made little impact on the two first plantings. However, serious outbreaks occurred in the 1940's when the post 192B groves came into bearing. The most important outbreak in the Kisaj»owe District was near Sanga-Sanga in 1941. The disease spread in eastern, then southern directions to Msonga and Magawa. It moved as well to the north across the* Luhute valley to Sotele and Binge. In both bisec tions the disease spread over a distance of approximately 40 kilometers during a period of 35 - 40 years. While this general direction of movement over an extended period of years was revealed by the survey, the spread did not occiir along an extended front and was often unpredictable. There was no apparent relation between the direction of spread of the disease and the prevailing winds although it spread faster through groves planted along open spaces like valleys or swamps. Similarly rampant spread of the lethal disease was reported from the Rufiji and Kilwa Districts. Outbreaks of the lethal disease were reported at various places along the coast of mainland Tanzania at various times from the 19th century onwards. Sometimes independent outbreaks occurred simultaneously. It is therefore impossible to recognize one or more sources from which the lethal disease originated. The disease has obviously been indigenous in the coastal areas of mainland Tanzania for a long time. Injection of both bearing and non-bearing diseased coconut palms with tetracycline-hydrochloride antibiotic resulted in remission of symptoms in test palms but only when injection was started in sufficiently early stages of disease. Total remission of symptoms was obtained in only one bearing palm, fill the other remitting palms showed delayed symptom development compared with their controls and succumbed later, The temporary symptom remitting bearing palms often produ ced new healthy inflorescences which blackened later. In non bearing palms, those which were injected in early stages of dise ase showed completely rnaffected spear leaves for a long time but nonetheless the palms collapsed later. Taken in conduction with the finding of MLO in diseased palms, these results support the concept of a MLC etiology for the lethal disease. Insect population studies at seven different lethal disease affected sites revealed that the insects occurring on ce conut palms in Tanzania are almost exclusively planthoppers (Fulgoroidea). Twenty-nine different species were identified at CAB Intitute of Entomology of which only seven were common at all sites.These seven species are the most likely candidates as the vectors of the agent causing the lethal disease. Seasonal peaks in the populations of several species were observed but they were neither clear nor consistent. No variety or hybrid was visited by consistently higher numbers of insects than any other. Removal of shade appeared to result in an incre- ase of insects on the palms* In transmission trials to find the vector of the lethal disease, only one test palm showed symptoms similar to those of the disease. However, the palm was observed in an advanced stage • and not sampled. This possible case of transmission needs confirmation.
Entomopathogenic nematodes and their potential for use against banana weevil {cosmopolites sordidus germar) in Tanzania.
(Sokoine University of Agriculture, 2009) Mwaitulo, Suma Andalwisye
A survey on the occurrence of entomopathogenic nematodes (EPNs) was conducted in selected banana fields in three regions (Coast, Mbeya and Morogoro) of Tanzania. The main objective of the study was to isolate entomopathogenic nematodes naturally occurring in banana fields in Tanzania and to test the effectiveness of these nematodes against banana weevil (Cosmopolites sordidus Germar). The presence of entomopathogenic nematodes is reported for the first time in Tanzania. Entomopathogenic nematodes were found in soils sampled from banana fields in Coast region of Tanzania using the Great wax moth, (Galleria mellonella L.) larvae as bait. Four (4.4%) out of 90 samples contained nematodes from which nine isolates of entomopathogenic nematodes were obtained. Seven isolates were identified as Steinernema spp while two isolates were of Heterorhabdits spp. The nine isolates were studied to determine their virulence against larvae and adults of C. Sordidus. Nematode concentrations of 0.35, 3.5 and 7.0 infective juveniles cm'2 were used. All isolates were able to invade C. sordidus larvae but adults were rarely infected. At concentrations of 3.5 and 7.0 cm' MK7A (Steinernema spp) and MK7B (Heterorhabdits spp) caused the highest larval mortality of up to 100%. The average larval mortality ranged between 52% - 78.67% with isolates MK7C and MK7B (Heterorhabdits spp) being the most virulent causing an average larval mortality of 77.33% and 78.67% respectively. The potential of using EPNs as a biocontrol agent for C. sordidus larvae based on laboratory results has been demonstrated. However performance of these isolates under field condition must be evaluated and tested. Proper delivery systems for use in different banana production systems need to be developed and tested.
Growth and yield response of selected cowpea genotypes to alecfra vogelii (bcnth) infestation in Dodoma, Tanzania.
(Sokoine University of Agriculture, 2011) Mtei, Marcel Thomas
The effects of Alecira vogelii was assessed by introducing cowpea genotypes that are resistant and/or tolerant under field conditions of Chamwino District in Dodoma. Specifically, the research aimed at assessing the effects of A. vogelii on shoot and root growth characteristics of cowpea and determining its effects on cowpea yield. Randomized complete block design (RCBD) with three replications was used. The experiment was set up at ARI-Hombolo and cowpea shoot biomass, root biomass. plant height and yield component data obtained were subjected to analysis of variance (ANOVA) using MSTAT-C computer statistical package. Tukey's honestly significant different test was used to compare treatment means. At 9 Week After Sowing Tumaini variety, genotypes IT 99K 205-8 and IT 99K 628 had significantly (P<0.05) low shoots biomass in gram/plant 15.6 g. 12.4 g and 14.2 g. respectively compared to IT 99K 494-6, IT 99K 7-21-2-2 and IT 97K 568-18 which had 18.9 g. 18.4 g and 17.1 g, respectively. Cowpea plant height of the local landrace (34.1 cm). IT 99K 628 (33.3 cm) and IT 99K 530-1 (38.5 cm) differed significantly (P<0.05) with the resistant genotypes IT 99K. 494-6 (47.6 cm). IT 99k 7-21-2-2 (54.1 cm) and IT 97K 568-18 (63.2 cm) at 9 WAS. The local landrace (664.3 kg/ha). IT 99K 628 (944.0 kg/ha) and IT 99K 573-1-1 (1128.0 kg/ha) had significantly (P<0.05) low yield compared to the resistant genotypes IT 99K 494-6 (2141.0 kg/ha), IT 99K 7- 21-2-2 (1536.0 kg/ha) and IT 97K 568-18 (2302.0 kg/ha). The seed weight per plant of the local landrace (10.0 g) and IT 99K 628 (16.1 g) differed significantly (P<0.05) from IT 99K 7-21-2-2 (23.4 g) and IT 97K 568-18 (23.2 g). Finally the findings revealed that, genotypes IT 99K 494-6, IT 99k 7-21-2-2 and IT 97K. 568-18 are resistant and all others are susceptible to A.vogelii strain of Dodoma.
Effect of genotype plant population and nitrogen fertilization on growth yield and quality of sunflower (helianthus annuus l.) grown under semi-arid conditions oF Central Tanzania
(Sokoine University of Agriculture, 2002) Mrosso, Leon Kasoromenya Wilbald
Field experiments were conducted at Msalato and Makutupora during the 2000/2001 cropping season to evaluate the effect of genotype, plant population and nitrogen fertilizer on growth, yield and quality of sunflower (Helianlhus annuus L.) grown under semi-arid conditions of central Tanzania. The experimental design was a split-split plot in randomized block with three replications. Two sunflower genotypes (The Open pollinated-Record variety and CRN 1435 a hybrid) were assigned to the main plots. three plant populations namely 55 555 plants ha'1 (60cm x 30cm), 44 444 plants ha'1 (75cm x 30cm) and 37 037 plants ha'1 (90cm x 30cm) constituted the subplots. Four levels of N fertilizer (0. 30, 60 and 90kg ha'1) were allocated to the sub subplots. Record variety (OP) produced significantly (P<0.05) taller plants, higher above ground biomass and larger seed size than CRN 1435 (hybrid). Plant spacing had no significant effect on plant height and dry matter accumulation. However, wider spacing recorded larger heads and higher dry matter production than narrow spacing. Nitrogen levels did not show significant effects. High values of dry matter accumulation were associated with high levels of N application. The hybrid CRN 1435 significantly (P<0.05) recorded higher number of seeds head'1, percentage oil concentration, seed yield and total oil yield (kg ha'1) than Record variety. Head diameter, number of seeds head'1, seed weight head'1 and one hundred seed weight were the yield components significantly (P<0.05) influenced by plant population. Percentage oil concentration, seed and oil yield (kg ha'1) were significantly higher at high plant population (i.e. at a space of 60 x 30cm). Nitrogen fertilizer did not record significant difference in terms of seed yield and yield components. The interaction between genotype and plant population was significantly recorded for yield components like head diameter, seed weight head'1 and one hundred seed weight with the highest values being recorded at 90 x 30cm spacing. Percentage oil concentration, seed and oil yield were significantly highest for CRN 1435 at 60 x 30cm. The hybrid CRN 1435 also produced more number of seeds, seed weight head'1. percentage oil concentration, seed and oil yield at 60 and 90kg N ha'1 as compared to other levels. Record variety did not respond to N application levels. The response of sunflower to plant spacing and N application was not statistically significant. However. high values for oil concentration, oil yield and seed yield was recorded at high plant population (60 x 30cm) when fertilizer was applied either at 30. 60 or 90kg N ha'1. respectively. Correlation analysis revealed that seed yield and total oil yield was positively and significantly correlated with number of seeds head'1, percentage oil concentration and seed weight head'1. Also oil concentration was significant and negatively correlated with head diameter and seed weight head'1. It is therefore concluded from this study that hybrid variety (CRN 1435) is superior to Record (OP) in terms of seed yield, oil concentration and total oil yield (kg ha'1). Narrow plant spacing has greater influence on oil concentration and oil yield than on seed yield. The N application levels were found to have similar effects for the parameters recorded except at 0kg N ha'1.
Effects of timing and frequency of leaf harvesting on leaf and seed yields of selected lines of cowpea (vigna unguiculata) in Morogoro, Tanzania
(Sokoine University of Agriculture, 2009) Rwegasira,Rozalia Gration
Cowpea [F7gna unguiculata (L.) Walp.J is consumed both as grain and as a vegetable. 1 practice, in East and West Africa the vegetable leaves are harvested from the same cro[. planted for seed production. The timing of leaf removal and subsequent frequency of the harvesting have great effects on the cowpea plant’s ability to recover from defoliation. An experiment was conducted at the horticulture unit of Sokoine University of Agriculture in Morogoro, Tanzania, to establish threshold levels at which timing and frequencies of leaf harvesting can be combined for optimal leaf and seed yields. Four cowpea lines (Vuli, UG-CP-9,1T97K10687 and Ngoji) were used as main plots in a split split plot design experiment where time to start leaf harvesting (20, 30 and 40 days after planting) was sub-plot treatment and harvesting frequencies of as per appearance, once a week, once in two weeks and no harvesting were sub-sub plots. The experiment was planted during the short rains season between September 2007 and January 2008. Data were collected on leaf yield, vegetative growth and seed yield. Harvesting as per appearance gave highest leaf yields but lowest seed yields. Delaying time to start leaf harvesting increased seed yields at the expense of leaf yield. Line Ngoji produced more leaves and had higher leaf yields than the other lines, but its seed production was low. In this study, the threshold level at which combined leaf and seed yields, with high enough proportion of seed yield of about 45% or more, was when time to start leaf harvesting was 30 days from planting with harvesting frequency once a week. When the threshold -2^jwel criterion was to achieve the highest combined leaf and seed yields, the best —nbination was harvesting at 30 DAP with frequency as per appearance except for line Vuli. With a threshold of monetary equivalent the best combination was when time to start leaf harvesting was 30 days from sowing (T30) with harvesting frequency as per appearance. It has been established also, however, that suitable timing to begin leaf harvesting and frequency of leaf harvesting for optimized leaf and seed yields is cultivar-specific.
Morphological and molecular genetic diversity of common bean (phaseolus vulgaris l.) varieties and landraces in Tanzania
(Sokoine Uninversity of Agriculture, 2014) Protas, Deogracious
Common bean (Phaseolus vulgaris L.) is among the most important crops in Tanzania. The production level has been increasing from 626 340 tonnes to 780 000 tonnes from year 2005 to 2012 respectively. Bean cultivation is highly adopted by small-scale and large-scale farmers. More than one hundred common bean genotypes including varieties and landraces have been collected from different geographical location in Tanzania, and little information is known about their variations. This study characterized sixty-four common bean genotypes by using morpho-agronomic traits and molecular genotyping by using SSR marker. Twenty morpho-agronomic traits were evaluated by using the common bean descriptor of IBPGR. Allelic loci were analyzed by using twenty-five SSR molecular markers. Among the major findings, the Principal component analysis (PCA) for the morpho-agronomic traits accounted 31% of the total variation of the genotypes analyzed; while the PCA from molecular data accounted for 37% cumulative variations for the common bean varieties and landrace analyzed. Results obtained enable the identification of the duplicates in our collection, separating the Mesoamerican gene pool from the Andean gene pool, identifying the relation between the varieties cultivation with their grouped landraces. This information helped in determining the pedigree of the background parent and were able to identify genotypes with important agronomic traits which plant breeders can use them in breeding common bean variety with more desired traits. This work is expected to be published in Academic Journal of African Journal of Biotechnology (AJB).
Small- scale horticultural production and household income in the peri-urban areas of mvvanza city – Tanzania
(Sokoine Univesiry of Agriculture, 2003) Ngissa, Sitta Ephraim Shimba
In many developing countries, Tanzania inclusive, the contribution of small-scale horticultural production at household and in the national economy is unknown. The output of the gardening sectors in developing countries is neither expressed in quantitative monetary equivalent terms, nor recognized as a significant contributor to household economies. This study seeks to determine the contribution of horticultural production in the promotion of income generation among the small-scale horticultural producers so as to show its economic contribution in comparison with other household’s sources of income. In year 2001 a study was conducted in Mwanza peri-urban areas to investigate the contribution of horticultural products to the household income. The study covered a total of 134 horticultural growers from 5 villages of Mwanza peri-urban. All of 134 respondents were sampled from 400 vegetable producers who were the beneficiaries of Mwanza Smallholder Horticultural Development Project - MSHDP also engaging in other economic activities. The results showed that horticulture growers are among the higher income earners in comparison with other agricultural cultivators of other crops such as cotton, cassava, maize and rice. About 19 per cent earned an income that ranged between Tshs. 300 001 -- 500 000 and 8.2% gained between Tshs. 500 001- 700 000 per year. In general, the income variation among the surveyed villages are very insignificant because the villages are located in the same kind of environment of Mwanza greenbelt. In other non- horticultural production, the study revealed that the income performance was very poor because 34.3 % of producers earned income that was less than Tshs. 100 000 and only 4.5% earned income between Tshs. 300 001 - 500 000 per horticultural grower. Also the survey revealed that more than 80% of the horticultural growers used their plots for cultivating cabbage and tomato. Furthermore the study shows that horticultural production created 1930 employment opportunities. The survey indicated that 52.2% of the farmers sold their produce to the city wholesale market and itinerary vendors. Therefore horticultural production is a chief contributor to the household as well as the national income in Mwanza peri-urban areas. Horticultural production is one of the industries, which employ people almost throughout the year in the agricultural sector than any other field of agricultural crops production in Mwanza region. It is high time economic and social development planners and policy makers recognized that horticultural production is one of the pillars of the household and national economy. What is needed is to make use of its potential value for which agricultural research and development programmes have overlooked for a long time.
Diversity and distribution of fruit flies (diptera: tephr1tidae) attacking pumpkin [cucurhita maxima duchesne ex lam ] in Zambia.
(Sokoine University of Agriculture, 2012) Mwape, Chiluba
The study on the diversity and distribution of fruit flies (Diptera: Tephritidae) in Zambia were carried out during the 2010/ 11 C (October to April). Three sites were selected in three agro-ecological regions. The aim of the study was to: establish the diversity of cucurbits infesters; assess infestation rate of fruit flies attacking pumpkin in Central Zambia; assess distribution and seasonal abundance of cucurbits infesters; determine the influence of climate on abundance of cucurbit infesters; and predict the potential distribution of Bactrocera cucurbitae in Zambia. Data on infestation rate were collected by random pumpkin fruit sampling in Central Zambia and rearing during the 2010/11 cropping season. Fruit flies collected from each site were identified to determine the species composition and diversity. The data on population dynamics were collected by installing cue lure baited traps at selected sites in three agro-ecological zones of Zambia. The influence of abiotic factors on population fluctuation was determined using simple correlation and linear regression models. CLIMEX’1 software package was used to predict the distribution potential of B. cucurbitae in Zambia. The study focused on fruit flies of economic importance that attack pumpkin. A total of 11 species representing the genera Dacus and Ceratitis were recorded in Central Zambia with Chilanga showing the highest diversity. The infestation for Dacus ciliatus was the highest compared to Dacus bivittatus and Dacus vertebratus. The dominant species in all the agro-ecological zones was Dacus bivittatus with insignificant Seasonal abundance differences. This was attributed to the availability of host fruits throughout the year. Reliable risk map for potential geographical distribution of B. cucurbitae was generated. An integrated systems approach for the management of fruit flies has been suggested.

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