Theses and Dissertations Collection

Permanent URI for this collectionhttp://10.10.97.169:4000/handle/123456789/39

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The effect of soil water deficits on growth and development of selected common bean cultivars (phaseolus vulgaris l.)
(Sokoine University of Agriculture, 1999) Maghembe, Neema Abdallah
Research was conducted to study the performance of three common bean (Phaseohis vulgaris L.) cultivars grown under stressed and non-stressed water conditions. Two experiments were conducted at Sokoine University of Agriculture (SUA) located at 6°.5’ latitude South, 37°.3’ longitude East; and 525m a.s.l The first experiment was conducted under screen-house conditions between March and May, 1998; while the second experiment was conducted under field conditions in May through August, 1998. The experimental design used was a split plot with four replicates. The main treatments were irrigated and non-irrigated. The subtreatments were three common bean cultivars. In the screen-house experiment, ten litre plastic pots filled with sandy clay loam soil were used for planting. Under the field experiment, the size of each subtreatment was 10.8m2 and the crop was spaced at 60 by 20cm. Sulphate of ammonia and triple supper phosphate were applied at 30kg N and 25kg P per hectare, respectively. Data were collected from underground and above ground plant parts at first flowering (Rl), 50% flowering (R4), physiological maturity (R8) and harvest maturity (R9). Highly significant effects of irrigation treatments, cultivars and their interactions were obtained at all sampling times except at R1 when the main treatments had just been applied. Non-irrigated plants completed their life cycle earlier than irrigated plants. Stressed cultivars had severe leaf curling, wilting and drooping between R4 and R8. Non stressed cultivars had significantly higher plants heights, leaf area, root length, total biomass and seed yield than drought-stressed plants. It was also noted that stress levels differ from one cultivar to another. Cultivar SUA 90 gave the highest total biomass and seed yield in both experiments under both maintreatments. This was followed by "Rojo" and finally Canadian Wonder. The BEANGRO crop simulation model indicated that root length, root weight, leaf weight, and specific leaf area were very important parameters to consider when evaluating bean genotypes for drought tolerance.
Improving maize production practices in a semi-coral area in Pemba
(Sokoine University of Agriculture, 2014) Omar, Ali Mohammed
Maize (Zea mays L.) is an important food crop grown in the semi-coral area in Pemba. Despite its high yield potential, it is giving low yields because of lack of appropriate information on varieties, plant population and fertilizer recommendations. Keeping this in view, the present study was done to establish the best combination of variety, plant density and nitrogen fertilizer for maximizing maize yield in the semi-coral area. Three improved varieties (Staha, Situka and TMV-1) were compared with the local variety (JKU) at three plant densities (44 444,53 333 and 66 666 plants/ha) and four nitrogen levels (23, 46, 70 and 90 kg N/ha) during the 2013 cropping season. A field experiment was laid out using a randomized complete block design in split-split-plot arrangement with three replications. Varieties were kept to the main plots, plant densities to the sub-plots and nitrogen levels to the sub-subplots. Results indicated that Staha produced significantly (P < 0.05) higher grain yield (4.953 tons/ha) followed by the local variety (4.411 tons/ha). The local variety flowered and matured earliest. Plant density had no significant effect on flowering, maturity and seed rows/cob but recorded significantly tallest plants (1.848 m) at 66 666 plants/ha and greatest yield (4.291 tons/ha) at 53 333 plants/ha. Application of 90 kg N/ha led to significantly (P < 0.05) tallest plants but delayed flowering and maturity while 70 kg N/ha was better for the yield and yield components. Interaction of variety with plant density, variety with nitrogen fertilizer and plant density with nitrogen fertilizer were all significant for the grain yield. Interaction of variety with plant density and nitrogen led to significantly highest grain yield (6.415 t/ha) from Staha with 66 666 plants/ha and 70 kg N/ha and therefore recommended for the semi-coral area.
Adaptability of selected snap bean genotypes and resistance to bean rust uromyces appendiculatus (pers.:pers.) unger var. appendiculatus) in Southern Highlands Zone of Tanzania
(Sokoine University of Agriculture, 2014) Kwigizile, owekisha hermas
Snap bean (Phaseolus vulgaris L.), also widely known as French bean or Green bean, is of growing importance in the socio-economic systems of East and Central Africa. It is a crop with great potential for addressing food insecurity, improving incomes and alleviating poverty in East and Central Africa. Most of the commercial varieties grown locally are highly susceptible to bean leaf rust caused by Uromyce appendiculatus fungus. Development of disease resistant varieties with acceptable pod quality is a feasible preference to alleviate the constraint. The present work centered on evaluating the adaptability and performance of snap bean genotypes and resistance to bean rust in the Southern highlands zone of Tanzania. Ten advanced bushy snap bean genotypes (HAB 404, HAB 425, HAB 449, HAB 423, HAB 240, HAB 427, HAB 442, HAB 403, HAB 414, and HAB 419 ), and the check variety Teresa were evaluated for agronomical characteristics, reaction to bean leaf rust, yield potential and pod quality using the Randomized Complete Block Design with three replications, at each location. The plot size was 1.5 m x 1.0 m, with two rows of plants spaced at 50 cm x 10 cm. Data was collected on growth habit, yield and yield components, and bean leaf rust score beginning 3, 5 and 7 weeks. Pod characteristics (color, shape, length (cm), width (mm) and snap-ability) were also assessed. The entries were scored for the bean rust at vegetative growth, flowering and at pod filling stages. Data was subjected to ANOVA using GenStart 14 Edition (2012) and means were separated using the Fisher’s Protected LSD at P = 0.05. Genotype HAB 427, HAB 425, and HAB 423, and HAB 240 were high yielder and showed resistance to bean leaf rust. Significant and positive correlations were also observed among genotypes on the yield and yield components. There were highly significant differences at (P<0.001) across sites on number of pods per plant, total pod yield and pod weight (g), 50% days of flowering and maturity. Interaction between genotypes and location showed also significant differences at (P<0.01) for the number of pods per plant and total pod yield (kg) per 10 plants harvested. Therefore; genotypes HAB 427, HAB 425, and HAB 423, and HAB 240 promised can be used as donor parental materials.
Effects of rice yellow mottle virus disease on performance of rice genotypes
(Sokoine University of Agriculture, 2014) Jomanga, Kennedy Elisha
Screen house experiments were conducted at Sokoine University of Agriculture during the season of 2011/12, to investigate the reaction and effect of Rice Yellow Mottle Virus (RYMV) disease on rice genotypes. Virulence among the three RYMV strains S4, 5 and 6 were tested. Disease reaction was observed on 1-9 scale. Results of pathogenicity test indicated that strain S5 was the most virulent strain followed by S6 and S4. Kalalu (resistant variety) was similarly affected by S5 as susceptible varieties. In experiment two and three, 52 rice genotypes were inoculated with RYMV strains S4 and S5, in order to identify rice genotypes resistant to RYMV disease. Results based on symptoms and grain weight indicated that eleven (11) rice genotypes were resistant/tolerance to RYMV disease. Grain weight reduction ranged from 1.01 to 43.69 %, while disease severity score of 1 to 5 were observed. These eleven rice genotypes were IR 73886-9-2-4-1-1, IR 71605-2-1-5-3-4, IR 69705-1-1- 1-4-2, IR 71028-3-1-2-5-1, IR 71029-3-1-5-5, Matata Gl, IRR 134, Matata G2, IR 69704-4-4-4-8-1-1-1, Adday Sei and IR 71027-43-3-2-B-3. Thirty seven (37) rice genotypes were susceptible, including SARO-5 and Supa (susceptible controls). The decrease in plant height and grain weight due to RYMV disease ranged from 12.01 % to 63.66 % and 48 % to 86 % respectively. The effect of RYMV disease on number of tillers per plant, showed both increase and decrease in tillers produced among inoculated genotypes. Therefore, future field research should focus on testing identified resistant rice genotypes against RYMV strain S5.
Effect of genotype x environment interactions on yield and grain qualities of rice (oryza sativa, L.) in Morogoro region
(Sokoine University of Agriculture, 2001) Kibanda, Nkori john Maregesi
Three experiments were conducted in the 1999/2000 season at Lumemo (rainfed lowland), Tanganyika Agricultural Cooperation (TAC) (irrigated) and Sokoine University of Agriculture (SUA) Farm (upland). The aim of the study was to determine the relative contributions of the newly obtained genotypes, environments and their interaction to the variations of grain yield, yield components and grain quality characteristics. Ten genotypes obtained from SUA and Kilombero Agricultural Training and Research Institute (KATRIN) were used in the experiments which were laid down in a Randomized Complete Block Design (RCBD) with three replications. The plot size was 4m x2m in which the plants were spaced at 20cm x 20cm. Data collected included the agronomic and grain quality characteristics, which were subjected to the analysis of variance, Correlation, Path coefficient and Stability analyses. The analysis of variance revealed that there were significant variations in the genotypes tested for most of the traits tested. Although there was significant genotype x environment interactions for most of the traits tested, early maturing lines SSD1, SSD3 and SSD5 performed better in all three environments. However, the late maturing genotypes performed better under supplementary irrigation at TAC. The results from correlation and path coefficient analyses revealed that the number of panicles/plant and percent spikelet fertility could be important characters that influence grain yield. Since these two characters also showed high heritability estimates, they could be used as indirect selection criteria for grain yield during early generations of rice breeding. Similarly for grain quality, estimates of heritability and genetic advance were high for gel consistency. From the results of this study, it can be provisionally concluded that early maturing genotypes may be grown in all three ecosystems in Morogoro region, while the late maturing genotypes are suitable in irrigated conditions or under rainfed with supplemental irrigation. Based on the overall performance and grain quality analysis, lines SSD1, SSD3 and SSD5 can be recommended for further evaluation in farmers fields.
The efficacy of some botanical insecticides againstcommon bean bruchids (zabrotes subfasciatus boh and acanthoscalides obtectus say)
(Sokoine University of Agriculture, 2008) Fivawo, Bernadeta Celestine
Laboratory studies were carried out to investigate the effectiveness of nine botanical extracts in three formulations for the control of common bean bruchids, Zabrotes sabfasciatus Boh. and Acanthoscalides obtectus Say. on common beans and to compare the performance of dust, water and oil extract formulations. Powder formulation of Ocimum canum, Tagetes minuta, Eucalyptus globus, Ricinus communis leaves and Neuteraunenia mitis tuber were tested under laboratory conditions. The effectiveness of the extracts was compared with actellic super dust a synthetic chemical (pirimiphos methyl + permethrin) commonly used for control of bean bruchids, T.minuta was the least effective botanical followed by R. communis, O. canum and E. globus while N. mitis was the most effective, the mortality of weevils after 14 days was 100% as that of Actellic Super Dust. The results indicate that all tested botanicals have potential for protecting bean seeds against infestation by bean weevils, but N. mitis is the most effective. Water extracts formulation of O. canum, T. minuta, E. globus and R. communis had lower efficacy compared to N. mitis and Actellic Super Dust which had performed better. Oil extracts of botanicals have shown higher efficacy on bean weevils as Actellic Super Dust, and therefore have potential for protecting stored beans against infestations. The result from this study showed that N. mitis extracts and all oil extracts have higher efficacy as that of Actellic Super Dust on protecting common beans against common bean bruchids. Hence, can be used efficiently as the recommended synthetic insecticides.
Genotypic-environmental effects on nut picking duration, yield and quality of seven cashew (anacardium occidentale l.) clones in South-Eastern Tanzania
(Sokoine University of Agriculture, 2019) Kapinga, Fortunes
An experiment was conducted in 2007/08 season at Naliendele, Nyangao and Nanyanga sites in South-Eastern Tanzania, to determine genotypic-environmental effects on nut picking duration, yield and quality of seven cashew (Anacardium occidentals L.) clones. The experiment was laid out in a Randomized Complete Block Design, with two factors arranged in split plot experiment; in which locations were the main-plot while clones replicated four times were the sub-plot treatments. Cutting-test carried out at NARI was used to determine nut physical quality. Nutritional values in the cashew kernels were evaluated at SUA, where fats and protein were analysed in DASP laboratory using Soxhlet Continuous Extraction and Kjeldalh methods, respectively. Minerals were analysed in soil science laboratory, where U-Visible Spectrometer was used to determine phosphorus content while atomic absorption spectrum was used to measure the quantities of calcium, magnesium, iron, zinc and copper. Flame photometer was used to measure potassium and sodium contents. Significant variations (P < 0.05) among clones were observed in all parameters studied. Clone AZA 17 consistently had the shortest nut picking duration in all sites, with an overall mean of 47 days. Cashew clone AC4 showed early crop maturity at Naliendele and Nanyanga, while clone AC4/285 matured early at Nyangao. The highest yield (3512.2 kg/ha) across the locations was produced by the clone AC4/285. Naliendele was considered most suitable site for cashew nut production because it gave the highest overall mean cashew nut yield (3530.0 kg/ha). Clone AC10 outperformed in nut weight (9.3 g), fat and protein contents. On the other hand, clone ACM was superior in mineral composition across the locations. This study also revealed that, high nut yielding clones are poor iniii nutrient contents. High yielding clones with short nut picking duration and early maturity characteristic were found to be important selection criteria for economical cashew nut production.
The role of improved sweet potato varieties to food security and rural livelihoods in Zanzibar, the Eastern and Lake Zones of Tanzania
(Sokoine University of Agriculture, 2005) Ishika, Mshaghuley Mcharo
The study was conducted to analyse the role of improved sweet potato varieties (ISPV) and popular highly grown local cultivars to food security in Zanzibar, Eastern and Lake zones of Tanzania. Study objectives were, to assess the rate of adoption of improved sweet potato varieties at farm level; to assess the production trends of ISPV; to assess the role of ISPV to food security; to identify the production constraints of ISPV and finally identify highly preferred local cultivars in the community. Multistage sampling technique was employed, 186 sweet potato grower households were sampled by random sampling. Data were collected through interviews using the pre-tested questionnaire and checklists for informal surveys (PRA). Secondary data was obtained from projects reports and electronically through Internet. Data were statistically analysed using SPSS to obtain frequencies, percentages, Chi-square, SAS were used for multivariate analysis using logit/probit regression model. Adoption of ISPV was found to be influenced by socio economic and institutional factors: extension service, participation and farming experience were statistically significant (P<0.05) between adopters and non-adopters. Majority (60.2%) of respondents reported high significant (P<0.05) increase in ISPV production compared to local cultivars, yet insignificant difference increase in acreage under ISPV was noted. Majority (70.4%) of respondents were growing ISPV and few (29.6%) were not growing. Majority of respondents (74.7%) were food secure and few (25.3%) were insecure. Sweet potato was found to be on transition from subsistence to commercial production. Major constraints identified were poor fanning and post-harvest improved technology, drought, pests and diseases, poor access to improved sweet potato vines, and marketing. Popular and highly grown local cultivars for food and market are. Pananzala/Mbutu, Matako mapana, Polista, Sekondari, Shangazi and Mkonibozi. Highly tiii adopted ISPV in the Eastern zone are Ukerewe and Simania, Lake zone are Jitihada, Simania and Sinia and Zanzibar Kizinibani inayai, Sinia and Simania. This study concludes that, ISPV play a greater role in household food security and generates income for their livelihoods. Its adoption was statistically significant though only few varieties were adopted. Thus research on potentials, opportunities, and constraints of the ISPV should be conducted. Plant breeders should develop improved varieties that have desirable traits for home consumption and for market.
Evaluation of new expressed simple sequence repeat markers for genetic studies and identification of cassava brown streak disease resistance
(Sokoine University of Agriculture, 2010) Mzena, Geradina Pantaleo
Evaluation for effectiveness of new expressed simple sequence repeat (ESSR) marker is an important component in the genetic improvement of cassava crop for agricultural development. ESSRs are often the markers of choice for genetic studies and identification of CBSD resistance. This study was aimed at: (i) Determining the optimum PCR conditions on annealing temperature and MgCh concentrations, ii) Identifying polymorphic loci for ESSR markers for genetic studies of cassava (iii) Identifying polymorphic loci of ESSR markers linked to CBSD. PCR amplification of each ESSR locus was optimized for annealing temperature and MgCh concentration. Variation at each ESSR locus was assessed in 24 cassava genotypes from 11 different countries all over the world. Successful amplification was achieved from a total of 68 primer pairs of which 53 showed polymorphism within the diversity of cassava genotypes panel. A total of 231 alleles were observed with an average of 4.35 alleles per marker and a range of 2 to 11 alleles. The PIC values measured by the frequency of alleles ranged from 0.173 to 0.844 with average allele frequency of 4.91. Fourteen (14) primer pairs were polymorphic to identification of genotype linked to CBSD resistance total of 63 alleles with average of 4.5 alleles per locus. These markers will be useful for application in genetic conservation and plant breeding. The genetic diversity observed by dendrogram revealed four major clusters and one sub clusters, varieties most closely related were Per 458 and Mex 55 (D=0.1732), TME 1389, and TME 1368 (D=0.1982), Mkita and Kalolo (D=0.3981) followed by Pesangani and Kigoma (0.4912) while distantly related genotype were these varieties BRA 990 and Mcx 55 (0.7089). Albert and Mkita (0.6036), BRA255 and Cubl (0.6054), TME 230 and TME 539 (D=0.59I4), and Namikonga and Albert (0.5139).
Mapping of single nucleotide polymorphism markers for tolerance to cassava brown streak disease of mkombozi x tms 4(2)1425 population
(Sokoine University of Agricuture, 2014) Salum, Kasele
Cassava Brown Streak Disease (CBSD) is a viral disease that impacts cassava tuberous root quantity and quality by causing a brown, dry, corky necrosis within the starch bearing tissues. Tire efficient way to control this disease is the use of resistant cassava varieties. This study was carried out to genotype the mapping population of Mkombozi x TMS 4(2)1425 and develop a single nucleotide polymorphic (SNP) genetic linkage map. Before SNP genotyping was done, the study to determine the integrity of 325 Fl individuals using ten polymorphic simple sequence repeat (SSR) markers to eliminate unknown parental combinations was done. SSR data revealed 158 true crosses, 135 off- types or admixtures, 31 selfs and one genotype (MT 210) was rejected due to many missing data. SNP genotyping was carried out using a reduced representation genotyping- by-sequencing approach at the University of Berkeley. Genetic linkage analysis was performed using Join Map software, version 4.1, Linkage analysis resulted in a total of 1136 SNP markers spanning 3207.9 cM assigned into 18 linkage groups (LGs) of the integrated linkage map. The average marker spacing of 3.4 cM that ranged from 1.3 cM to 10.1 cM was observed from this population. The total of 802 SNP markers were distributed on 19 LGs of female parent (Mkombozi) spanning 2848 cM with an average marker spacing of 3.7 cM ranging from 1.7 to 6.2 cM. On the male parent (TMS 4(2)1425), 593 SNP markers were distributed on 18 linkage groups spanning 2482.8 cM with average marker spacing of 5.2 cM ranging from 1.9 cM to 12.6 cM. The genetic linkage map developed in this study will be used for the identification of molecular markers and quantitative trait loci (QTLs) associated with CBSD tolerance in Mkombozi. The molecular markers and QTLs identified provide useful materials to breed and select CBSD resistance cassava varieties through marker-assisted selection (MAS).
Rural and urban household demand analysis for cassava in Dar es salaam and Coast Region, Tanzania
(Sokoine University of Agriculture, 2016) Msuha, Basil
Cassava is one. of the most important root and tuber crops mostly grown for food in Tanzania, though in Africa, it is a marginalized crop in food policy debates burdened with the stigma of being an inferior food. This study examined the major factors that drive changes in cassava consumption pattern across income groups and consumer characteristics among urban and rural households to inform food policy formulation. The study, among other things, sought to provide evidence on whether or not cassava had become a normal food commodity in selected urban and rural households. Special attention was also given to the question of whether household social demographic characteristics had any significant effect on cassava consumption. Cross sectional household data were used to estimate single equation demand models by employing Working-Leser Engel model through the use of OLS method. Cassava expenditure elasticity was estimated for selected urban and rural areas across different income groups to test Engel’s law. Descriptive analysis was used to identify the most preferred form of cassava product among consumers. The results revealed that boiled cassava is the most preferred product in the study areas. The empirical evidence failed to reject the hypothesis of no relationship between household’s preferences and income levels thus lead to the conclusion that the household’s preferences to cassava products is independent of their income levels, whether low, middle or high income, almost all households bought a particular cassava product based mainly on their own assessment of the taste. The study provided empirical evidence to reject the hypothesis of no difference in mean household expenditure and cassava budget share between urban and rural households in the study areas and lead to a conclusion that monthly average total households expenditure was different in
Developing top cross maize (zea mays l.) hybrids tolerant against maize streak virus (msv) disease for the Eastern zone ecologies
(Sokoine University of Agriculture, 2014) Jalalambegu, Salum
Maize production in smallholder farming community has remained low due to a number of constraints which include biotic and abiotic. Among biotic constraints, Maize streak virus (MSV) disease is one of the major causes of low yield if not controlled. Genetic resistance appears to be the best economical option to control MSV and it is readily adopted as method for smallholder farmers, because of less cost and environmentally friendly. The main objective of this study was to produce high yielding top cross maize hybrids which are tolerant to MSV disease for growing in the Eastern ecologies of Tanzania. Staha (female) and fourteen inbred lines (male) were used to produce top cross hybrid genotypes. Evaluation for MSV resistance was done under natural infection. RCBD replicated three times was used in three selected MSV hot spots of Eastern areas of Tanzania. Fourteen top cross hybrid genotypes and two checks were used. Highly significant variation (P - 0.001) was found among the genotypes for MSV and grain yield. Dak0127, Dak0122, Dak0125 and Dak0124 genotypes were identified as the best materials for yield and tolerant to MSV disease while Dak0123, Dak01211 and Dak01210 genotypes were not good for locations having high MSV disease pressure. Significant and positive correlations between yield and plant height, ear length, hundred seed weight and ears/plant were observed. Path coefficient analysis indicated importance of the same variables through their direct contribution on grain yield. High heritability was observed for grain yield, ear length, number of rows/ear, grains/ear and grains/row, MSV disease incidence and severity, ear height, ears/plant, ear circumference, plant height. Based on correlation analysis earlier silking should be used for increased yield at theseiii locations. High yielding MSV disease tolerant top cross genotypes which were identified are recommended for more seasons’ evaluation for identifying genotypes to replace existing inferior cultivars.
Implications of epigenetic variation during nodal micropropagation for substantive equivalence analysis: case study Cassava (Manihot esculenta Crantz)
(Sokoine University of Agriculture, 2014) Kitimu, Shedrack Reuben
Transgenic plants are rapidly being adopted in parts of the world as a result of increased food demand due to growing population and decrease in agricultural production following dramatic changes in environment. Transgenic crops are accepted for import for food and feeds use and for release into the environment in different countries in the world. For vegetative propagated plants, there is always a phytosanitary concern for international exchange of materials, which require the use of tissue culture as a means to produce virus free plantlets that can then be transported across international boundaries without presenting a quarantine hazard. Although in vitro propagation systems that are based on the use of micro cuttings are widely viewed as being analogous to field cuttings, much is not known about the possible epigenetic changes induced by this type of micropropagation. In this study, we survey for epigenetic changes during propagation by node culture and by field cuttings of five cassava (Manihot esculenta Crantz) varieties. Genome-wide DNA methylation profiles revealed by Methylation Sensitive Amplified Polymorphism (MSAP) uncovered consistent epigenetic differences between clonal materials recovered from in vitro nodes and from those produced from stem cuttings. Also, the observed epigenetic variance between different organs from the same plant was greater between tissues from field grown plants than that observed between organs secured from in vitro propagated plants. In this study we uncover differential methylation markers at several loci that could be implicated at organ differentiation and maturation in cassava. We explore the significance of these findings when seeking to predict potential effects to transgenic cassava when imported in tissue culture form and its consequences to the crop physiology and performance during field trials before it is proved substantially equivalent to their traditional local isogenic comparators. vi
Yield and quality of sweet potato as affected by number of nodes buried and potash fertilizers
(Sokoine Univesity of Agricuture, 2014) Kalaye, John
A study was conducted from January 2013 to June 2013 at Hombolo Agricultural Research Institute in Dodoma, Central Tanzania. The aims were to evaluate response of three sweet potato varieties in productivity and quality to four levels of nodes buried and three potash fertilizer sources. A Split-split plot designs was employed and treatments were applied. Main plot were three sweet potato varieties, Kiegeya, Mataya, and Ukerewe. Sub plot were, nodes burring levels: four buried nodes, (two above ground), five buried nodes (three above ground), seven buried nodes (three above ground) and eight buried nodes (four above ground). The sub - subplot treatments were potash fertilizer sources: Control no fertilizer used, Potassium chloride (KC1), Potassium nitrogen phosphate (NPK) and Farm yard manure (FYM). Results indicated total yield were not affected by varieties planted. There were significant differences among number of nodes on the total yield, the lowest total yield (11.68 t ha'1) was from four buried nodes whereas the highest yield of (15.91 t ha'1) was from eight buried nodes. The application of fertilizers at the rate 120 kg ha'1 significantly influenced the yield components (P <0.05). The lowest number of tuber roots (2.81) was from control treatment while the highest number of tuber roots (6.03) was from KC1 treatment. The indicators of tuberous root quality such as diameter (4.81 cm), length (19.03 cm) and weight (0.42 kg plant'1) were from KCL The total tuber roots yield (18.84 t ha'1) from KC1, (17.51 t ha’1) from NPK, (11.33 t ha'1) from FYM and (8.82 t ha'1) with control treatment. Seven and eight buried nodes with KC1 and NPK fertilizers appeared appropriate for optimum sweet potato growth, yield and tuberous root quality in the study area and are therefore recommended.
Kimaro, Didas Rogasian
(Sokoine University of Agriculture, 2012) Development and morphological characterization of cowpea (vigna unigniculata) lines for drought tolerance
Development of drought tolerant cowpea varieties is an important aspect in breeding programmes. The main objective of this study was to introgress drought tolerance into farmer’s preferred cowpea varieties. A total of 32 cowpea lines were obtained by crossing 1TOOK-1263 with Tumaini and ITOOK-1263 with X-Ilonga cowpea varieties in a screen-house experiment laid out in a completely randomized design (CRD) with a split plot arrangement in three replications. The F| lines were advanced to Fj generation and screened for drought tolerance using box method. The results indicate the following lines are drought tolerant ITK-TMA4. ITK-TMA10, ITK-TMA13. 1TK-XL1 and ITK-XL9. Heritability estimates were high for all variables in both crosses except for seed yield for plant recorded at 24.41% in a cross between ITOOK-1263 x X-IIonga. Moisture stress during vegetative stage has more effect than moisture stress at flowering stage for morphological characterization under moisture deficit. The principal components (PC) analysis revealed that the first two PC contributed 99.65% of the total variation among the 18 cowpea genotype evaluated for cross between ITOOK-1263 and Tumaini. The PCI and PC2 accounted for 93.85 and 5.80 of the total variation respectively. While that of ITOOK-1263 x X-Ilonga contributed 99.78% of the total variation. The PCI and PC2 accounted for 89.75 and 10.03 of the total variation respectively. Using the PC analysis, this study concludes that the most effective trait responsible for variability among the cowpea genotypes were days to 50% flowering, days to maturity and number of seeds per plant. Further studied are recommended on drought tolerance lines generated in this study, particularly: advancing up to F6 and evaluation for other abiotic and biotic factors.
Evaluation of selected crop starches as an alternative cheap gelling agents for micropropagation of sweet potato (ipomoea batatas l.)
(Sokoine university of Agriculture, 2009) Madege, Richard Raphael
Experiments were conducted to investigate cheap gelling agents as substitutes to agar in order to reduce the cost of micropropagation. Starches from cassava, sweet potato, irish potato, wheat, sorghum, maize and rice were tested together with 0.08% (w/v) agar as control and sweet potato cv. Ukerewe was used as test plant. Standard methods of determining physicochemical properties of the starch and Tissue Culture (TC) were used. Nodal explant cultures were initiated in MS (Murashige and Skoog, 1962) media supplemented with 3% sucrose and 0.5mg/I Benzyl-Amino-Purine and gelled by seven starches each at concentrations: 12%, 15%, 18% and 21% (w/v). In vitro nodal explants were subcultured individually on fresh media supplemented with 3% sucrose, 5 mg/1 gibberellins and solidified by 15% cassava, 11% sweet and irish potato starches. During culture initiation, Cassava, sweet and irish potato starches outperformed the control in influencing the number of leaves, nodes, height and fresh weight of in vitro shoots. Of the three starch gelled media, sweet potato starch based media had the highest micropropagation rate of 2058 in vitro nodal propagules in 84 days but it was lower than that of the control which produced 3584 in vitro nodal propagules during the same time. Highest media and propagule cost reduction of 44% and 67% respectively was achieved by using sweet potato starch instead of agar. Therefore, sweet potato starch has high potential to replace agar due to good plant growth and low cost of the media.
Drought tolerance assessment of cassava genotypes in a semi-arid environment in central Tanzania
(Sokoine University of Agricuture, 2014) Kachiwele, Andrew Zebedayo
Drought tolerance is an increasingly important trait in cassava due to globally dwindling water resources, a shift in production areas and increasing input costs. This study was conducted to evaluate eighteen cassava genotypes for drought tolerance to counteract frequent shortages of rainfall. An experiment was set in Dodoma, Tanzania which is a drought-stricken environment where cassava genotypes were grown under watered and water stressed conditions. Identification of drought tolerant genotypes that also had good yield potential was facilitated by the stress treatments used on farm. Morphological (leaf length, leaf width, plant height), physiological (leaf retention, chlorophyll content), biochemical (Catalase and Peroxidase enzymes activities) and yield (number of roots per plant, yield in tons per hectare, above ground biomass, percentage diy matter content and harvest index) attributes were used to assess tolerance of the tested genotypes to drought stress. During harvesting, on farm farmers participatory evaluation and organoleptic test were also conducted to enable farmers select best genotypes based on consumers criteria. It was found during the study that water stress had profound effect on growth, physio chemical and yield performance of cassava genotypes. All attributes measured were significantly influenced by drought except leaf length atl80 DAP, plant height at 120 and 150 DAP, number of roots per plant, weight of above ground biomass and harvest index (P<0.05). Generally water stress suppressed both growth and yield of the crop. Through the study, superior drought promising cassava genotypes identified were 92B/00073, KBH 2006/363, KBH 2006/12 and KBH 2006/18. These genotypes performed well under stress and well watered conditions and thus may serve as parents for drought stress improvement and genetic analysis.
Effects of harvesting intervals and quality of planting materials on cassava brown streak disease and yield of cassava
(Sokoine University of Agriculture, 2014) Biswao, Yongolo Mary
Investigations were conducted at Kibaha Sugarcane Research Institute, Coast region, Tanzania to identify cassava brown streak viruses (CBSVs) and their variants by Real-Time Polymerase Chain Reaction (RT-PCR) and to assess the effect of time of cassava harvesting on quality and yield loss associated with cassava brown streak disease (CBSD) infection. This study was prompted by the reported reduction in yield of cassava in Tanzania caused by CBSD. Two field experiments were conducted where the first sought to evaluate the effect of CBSD on above ground yield components and root yield of CBSD-infected and CBSD-free planting materials of Kiroba cassava variety. The second experiment assessed the effect of harvesting time on yield and quality traits for virus-free planting materials of Kiroba and Mwari varieties. The viruses (CBSV and UCBSV) were identified using RT- PCR assays from 220 cassava leaf samples of both varieties. Results indicated that plants affected by CBSVs may or may not express symptoms of CBSD but only molecular (PCR) diagnosis can be used to confirm the presence of either or both of the causal viruses. Use of CBSD-infected planting materials of Kiroba decreased root weight by 24%. However, the symptoms of CBSD were delayed for the plants whose planting materials were free from virus. The highest incidence (24.3%) of root necrosis for Mwari was recorded at 14 months after planting (MAP) and at the highest level of CBSD incidence (5.2%). Kiroba had the highest incidence (22 to 26.8%) of root necrosis from 12 to 16 MAP at the lowest (0%) to the highest CBSD incidence (14.5%). The highest yield (8.8 t ha'1) for Mwari was recorded at 14 MAP, which dropped to 8.0 t ha'1 at 16 MAP. The highest yields (8.1 and 9.3 t ha'1) foriii Kiroba were recorded at 14 to 16 MAP. It was recommended that virus-free planting materials should be used in order to avoid spread of CBSVs and reduce the intensity of root necrosis. More studies should be conducted using similar planting materials in a non-isolated field and during the second growing season to ascertain the reproducibility of the findings of this study before the findings are recommended to farmers
Efficacy of bio-toxicant (derris elliptica) baits on two major fruit flies species (diptera: tephritidae) in Morogoro, Tanzania
(Sokoine University of Agriculture, 2017) Bwire, Patroba
From this study we recommends that all solvent extract used in this study are potentially solvent extract for plant bio-toxicants especially dichoromethane, petroleum ether and methanol however water also do better but more study should be done on it and the selections should be based on the polarity and less harmful to human health and untargeted organisms.
Response of the larger grain borer [prostephanus truncates (horn)] to varietal variations in resistance of maize
(Sokoine University of Agriculture, 2001) Kamwela, Daniel Shabani
This study was carried out to investigate the response of the larger grain borer Prostephanus truncatus (Hom) to variations in resistance of maize varieties. Thirty-one (16 local, 8 composites and 7 hybrids) maize varieties were used as treatments. The response of P. truncatus was investigated by determining the following parameters: number of adult progeny, oviposition. larval and pupal duration and adult emergence pattern. For each of the maize cultvars, grain damage, weight loss and susceptibility indices were calculated. Prostephanus truncatus was found to respond differently to the maize varieties. Significant variations in numbers of adult progeny, number of eggs, larval and pupal mortality were observed among maize varieties. The highest susceptibility index was recorded in a hybrid variety H6302. Percentage dry-weight loss and percentage damage showed significant variations among maize varieties. Varieties H6302, H 614, MH51, TMV2 and Katisini were the most damaged by the pest. The shortest and longest larval duration were recorded in varieties H6302 and UCA, respectively. Adult emergence was highest in the hybrid varieties. Both larval and pupal mortality were found to vary significantly (P < 0.05) among maize varieties. The lowest percentage larval and pupal mortality was recorded in H6302 while the highest percentage pupal and larvae mortality was recorded in Kilima. It is concluded that varietal resistance can contribute to the reduction of damage and weight losses of stored maize by P. truncatus. Identification and incorporation of the genes or factors responsible for inherent resistance to storage pests can greatly contribute to the effectiveness of integrated pest management (IPM) strategy for this pest.

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