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Effects of yellow witchweed (Alectra vogelii) strains on performance of improved cowpea (Vigna unguiculata (L) Walp.) Genotypes
(Greener Journal of Agricultural Sciences, 2021-12-31) Reuben, F.M.; Tryphone, G.M.; Kudra, A.B.
Witchweed (Alectra vogellii) has continuously remained a great challenge for cowpea production in sub-Saharan Africa. Developing resistant and stable high yielding cowpea genotypes in Alectra infested areas requires evaluation of available cowpea germplasm for resistance against the weed. To achieve this, an experiment was conducted in the screen house at Ilonga Agricultural Research Institute (ARI- Iloga), Tanzania in 2017 to determine how selected cowpea genotypes fair in soils infested with different Alectra strains. The experiment comprised of two factors namely A. vogellii strains as the main factors and cowpea genotypes as sub-factors and was carried out as a spilt plot experiment arranged in randomized complete block design with three replications. Results revealed significant differences amongst cowpea genotypes on days to first Alectra emergence and number of emerged Alectra shoots. The cowpea genotypes B 301, Mkanakaufiti, Vuli AR1, Vuli AR2 and Vuli-1 allowed Alectra emergence at 42.83, 37.25, 36.75, 37.42 and 33.17 days after planting (DAP), respectively. There were variations in number of Alectra shoots supported by genotypes, as 1.0, 5.0, 4.0, 5.0 and 14.0 for B301, Mkanakaufiti, Vuli AR1, Vuli AR2 and Vuli-1, respectively. The genotype B 301 recorded the lowest number of Alectra shoots, reached 50% flowering earlier and had the highest seeds and pods weight and highest number of pods per plant. Contrarily, the genotype Vuli-1 produced the highest number of seeds per pod and was the first to reach 95% physiological maturity. The genotype B 301 was identified to possess a high level of resistance to A.vogelii infestation and accordingly was deemed as a useful source of resistance genes in cowpea resistance breeding programs.
Selecting for coupling-phase recombination between potyvirus resistance and white endosperm colour in maize preferred by farmers in sub-saharan Africa (SSA)
(Afrika focus, 2019) Bulegeya, Victoria B.; Jones, Mark W.; Muhamba, Tryphone G.; Das, Biswanath; Thomison, Peter R.; Francis, David M.; Redinbaugh, Margaret. G.
Maize lethal necrosis (MLN) disease caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any cereal infecting potyvirus is a threat to food security in Sub-Saharan Africa (SSA). Resistance to potyvirus has been extensively studied and Mdm1 gene for potyvirus resistance on chromosome 6 of maize is linked to Y1 gene for maize endosperm colour. This study is aimed at se- lecting for coupling-phase recombination of potyvirus resistance and white endosperm colour. White susceptible maize lines CML333 and CML277 were crossed with a yellow resistant line, Pa405, to produce F1 and F2 progenies. Progenies were screened using molecular markers to recover 22 white endosperm recombinants. 22 selections were advanced to F3 recombinant families, and 10 were as- sayed for their responses to Maize dwarf mosaic virus (MDMV) and Sugarcane mosaic virus (SCMV). Four families segregated for SCMV resistance, selection of homozygous recombinants within these families will provide lines appropriate for improving lines with resistance to SCMV and MLN resistance in SSA.
A Review of options for speeding the adoption of climate smart varieties: what works and what does not work: Experiences from Tanzania
(nternational Journal of Environment, Agriculture and Biotechnology, 2022-06-08) Bilaro, Atugonza Luta; Tryphone,George M.
Given the efforts invested on addressing climate change adaptation particularly in agriculture, the adoption of climate smart varieties has not met the expectations. A number of crop varieties developed targeting drought prone areas largely remained un-adopted hence unknown to the majority of farmers or lack traits deemed special for adaptation to climate change in target areas. Variety adoption rate is highly dependent on its adaptation to particular environmental conditions including suitability to tolerate drought, salinity and acidity and ability to meet different livelihood needs such food, fodder and cash. Poor adoption emanates from lack of awareness and the volatility of the farming environment coupled with poor integration of seed business into private public partnership. Rapid adoption of climate smart varieties in Tanzania would require better policy intervention with a well-organized extension system and modifications in variety testing procedures, including the current guidelines for variety release. In this work the authors discuss some approaches that can be used to enhance the adoption of climate smart varieties in Tanzania and cite a few specific cases based on experience from Tanzania.
Cost-benefit analysis of the selected weed control options in cassava production system
(Greener Journal of Agricultural Sciences, 2021-12-31) Leonard, Joseph A.; Kudra, Abdul B.; Tryphone, George M.
Weeding activity is one of the major constraints in cassava production as it requires highcapital and it takes 50 to 80 percent of the total production budget. Based on this fact, there is a need to determine the most economical integrated weed control option(s) thatwill effectively control weeds and minimize cost of production. The effect of different weed control treatment combinations was studied and the most economical one(s) were determined during 2019/2020 planting season at Ilonga village, Kilosa and Kiimbwanindivillage, Mkuranga, Tanzania. Till only and till + Ridge, pre-emergence herbicides Primagram Gold a.i 290 g L S-metolachlor + 370 g L atrazine and Oxfen a.i Oxyfluorfen 24% EC), post emergence herbicides (Force up a.i 480 g/L of Glyphosate- Isopropylamine salt and back pack weeder were tested on Cassava variety Kiroba in a (2× 2 × 2) factorial experiment arranged in a randomized complete block design (RCBD) with three replications. Data collected were all variable costs for the inputs applied oneach weed control treatment combination, costs of cassava harvest and the price of cassava per one kilogram. Data were subjected to benefit-cost ratio analysis. Results revealed that, at Mkuranga site, till × Oxfen × Force up and till × Primagram × Force up treatment combinations had high benefit cost ratio of 2.39 and 2.04 respectively while at Integrated weed Kilosa site, only Till and Rigde × Oxfen × Force up treatment combination had high benefit cost ratio of 2.31. These high benefit cost ratios indicate feasibility of using control option(s), Benefit cost respective weed control combinations in cassava production. Therefore, good farm ratio. preparation, the use of Oxyfluorfen 24% EC herbicides as pre-emergence herbicide and -1 480 g L of Glyphosate-Isopropylamine salt as post emergence weed control treatments are recommended in cassava production systems.
Response of spodoptera frugiperda larval instars to commonly used insecticides in Tanzania
(Asian Plant Research Journal, 2022-12-24) Kiva, F. Mbemba; Tryphone, G. M.; Rwegasira, G. M.
Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a polyphagous migratory pest reported in Tanzania in 2017. Limited choices of officially registered insecticides for the control of the pest when it first occurred led to many farmers opting for the few available ones including those that were not registered for the pests. The current study drew from a survey conducted in 2018 that listed the insecticides commonly used by farmers against the pest. The study assessed the effectiveness of the insecticides against the different S. frugiperda larval instars under field conditions in the 2019 and 2020 growing seasons. Ten commonly used insecticides were applied to S. frugiperda damaged maize crops. Obtained results suggested a varied effectiveness of the tested insecticides with some inflicting significant (p < 0.001) mortality of S. frugiperda larvae while some proved ineffective. Ninja plus 5EC, Profecron 720 EC, Multi alpha plus 150 EC and Duduba 450 EC, caused highest mortality of S. frugiperda in all experimental plots accompanied with reduced incidences and damage severities on maize crops while Thunder 145 OD and Attakan 350 SC were the least effective. Yields obtained from the experiments suggested a significant impact of applied insecticides whereby plots treated with Duduba 450 EC produced the highest yield (4 tons/ha) compared to non-treated plots (2.2 tons/ha). The findings from this study prove that some insecticides were effective against the pest while some were not. As such farmers’ complaints on the ineffectiveness of traded insecticides could be real.
Identification of drought selection indices of common bean (Phaseolus vulgaris L.) genotypes in the Southern Highlands of Tanzania
(African Journal of Agricultural Research, 2019-12-05) Mazengo, Karantin D.; Tryphone, George M.; Tarimo, Akwilini J. P.
A study was conducted to evaluate common bean (Phaseolus vulgaris L.) genotypes for drought tolerance in the Southern Highlands of Tanzania. Treatments included 18 genotypes laid out in a 3×18 split plot arranged in randomized complete block design with three replications. The data on yield under water stress and non-water stress treatments were used to calculate indices that can be used for predicting tolerant genotypes. This was accomplished by ranking the yield indices within the selection indices. Results showed that, selection index, YI, identified BFS60, KG104-72 and SER16 as the most tolerant genotypes, while STI, MP and GM identified SER16, BFS60 and KG104-72. Another index, SSPI, identified RCB266, 41-EX-VAM and SER83 as most sensitive genotypes to water deficit while HM showed BFS60, SER16 and KG104-72 as genotypes tolerant to drought. In contrast, SSI discriminated 41-EX-VAM, RCB266 and PASS as most susceptible genotypes under drought. Ranking the means of yield indices, genotypes SER16, BFS60 and KG104-72 were identified as the most drought tolerant genotypes. Correlation analysis showed that Yp were highly significant (p < 0.001) and positively correlated with STI, SSPI, MP, HM, and GM while Ys were highly significant (p<0.001) and positively correlated with YI, STI, MP, HM and GM. The findings suggest that these indices are effective for discriminating genotypes with higher yields under non stress and stress conditions, respectively. Genotypes, SER16, BFS60 and KG104-72 are among the most tolerant to drought conditions therefore are recommended for cultivation in drought prone environments and subsequently as parental materials in breeding for drought tolerance.
Response of common bean genotypes (Phaseolus vulgaris L.) to drought for growth and yield characteristics in the Southern Highlands of Tanzania
(International Journal of Environment, Agriculture and Biotechnology (IJEAB), 2019) Mazengo, Karantin D.; Tryphone, George M.
Common bean cultivation is affected by drought up to 60% worldwide and makes the second for yield loss contribution after diseases. Despite the loss, it is estimated that over 75% of rural households in Tanzania depend on common bean for daily sustenance. The objective of the study was to evaluate the response of common bean genotypes in growth and yield characteristics under induced moisture stress in the field at Inyala Agriculture Training Institute in the Southern Highlands of Tanzania. In this study, eighteen common bean genotypes investigated included SER125, MR13905- 6, and 41-EX- VAM, BFS20, RCB233, CZ109-22, CZ104- 61, KG25-21, SER82, PASS, SER83, KG104-72, SER16, KG4-30, SER45, SER124, BFS60 and RCB266. The experiment was designated in a 3 x 18 split plot arranged in a complete randomized block design (CRBD) with three replications. The main plots were the three moisture treatments such as non moisture stress, stress at flowering and stress at mid pod filling and the sub plots were the common bean genotypes. The plants’ variables recorded were number of days to 50% flowering, number of days to 85% maturity, number of pods per plant, weight of pods per plant, weight of seeds per plant, number of seeds per pod, 100 seed weight and yield per hectare. The collected data were subjected to analysis of variance (ANOVA) using GenStat computer software 14th edition. The results showed significant (p < 0.05) differences between moisture treatments and bean genotypes. Genotypes SER16, BFS60, KG104 -72 and CZ109-22 were significantly superior in grain yields Also, BFS60 was recorded with highest number of pods per plant, weight of pods per plant and weight of seeds per plant, while KG104-72 was recorded as the earliest in 50% flowering and 85% maturity. Genotype SER16 also excelled in weight of seeds per plant. These genotypes therefore can be considered as drought tolerant common bean genotypes and also can be used as parental materials for breeding programmes.
Evaluation and differential expression of genes conferring drought tolerance in selected maize genotypes in the Morogoro Region of Tanzania
(African Journal of Agricultural Research, 2018-06-26) Kanyairita, Gertrude G.; Mortley, Desmond G.; Muhamba, George T.; Egnin, Marceline; Bons, Conrad K.
Experiments were conducted at Sokoine University of Agriculture in Morogoro, Tanzania to assess the growth performance and grain yield of ten maize cultivars under well-watered and water stressed conditions. The ten cultivars (CML 444, CML395, CML539, WE 4107, WE 2112, WE 3102, WE 4112 and WE 4116) obtained from Water Efficiency Maize for Africa (WEMA) project and two local market cultivars (‘STAHA’ and ‘TMV1’) were grown in a Randomized Complete Block design with a 10×3 factorial treatment arrangement and three replications. The three drought stress treatments were 50, 75 or 100% of field capacity with 10 kpa (equivalent to field capacity) and 30 kpa (drought) using tensiometers. Drought stress was initiated at vegetative stage (three weeks after emergence) for thirty days and flowering stage (one week before to two weeks after flowering). Plant height, stem diameter, leaf length, leaf width and chlorophyll content were measured at weekly intervals from two weeks after planting to maturity. Days to anthesis and silking were used to calculate Anthesis-Silking Interval (ASI) and kernel dry mass were recorded at harvest. Vegetative growth responses were not affected by water stress, but plant height and leaf chlorophyll content tended to decrease, while ASI ranging from 5.2 to 11.1 days and kernel dry mass decreased with increased drought stress. Dry kernel weight was significantly greater among five of the cultivars designated drought tolerant and the lowest in the two drought susceptible cultivars. Drought tolerant genes were expressed at different levels and only a few cultivars expressed all three genes at the vegetative and flowering stages. Thus, vegetative response of maize to drought stress varied based on cultivars. However, it appears that drought stress exerted more impacts on reproductive processes compared to vegetative.
Identification of genetic variability among Alectra vogelii strains from different geographical locations
(Journal of Current Opinion in Crop science, 2021-09-25) Reuben, F. M.; Kudra, A. B.; Tryphone, G. M.
Alectra vogelii threatens cowpea production in Sub-Saharan Africa. The weed complicates the development and operation of effective control tactics. For DNA extraction, young leaf samples of A. vogelii were taken directly from infested cowpea fields. The study used 23 SSR markers to determine genetic heterogeneity among A. vogelii populations, which will help design and implement effective breeding techniques and other parasite control approaches. The effective number of alleles was 1.5648, the observed number of alleles was 8, the anticipated heterozygosity was 0.648, and Shannon's Information index was 0.5169. PIC was 0.8301 on average. The Fst between populations was 0.2986, leaving 70.14 percent genetic variation within populations. A NTSYS -pc (UPGMA) dendrogram developed three clusters. More information on genetic heterogeneity among existing Alectra strains was gathered to help expand the cowpea gene pool for selection and creation of resistant genotypes.
Evaluation of some common beans (Phaseolus vulgaris L.) genotypes for efficiency in using phosphorus for grain yield and yield components
(Net Journal of Agricultural Science, 2018-09-06) Kilango, Michael A.; Muhamba, Tryphone; Mbega, Ernest
Common beans (Phaseolus vulgaris L.) are important supplementary protein sources and soil nutrient restorer for subsistence farmers in Tanzania. Yields of common beans, however, are limited by low soil fertility, as they are grown in poor soils, often without fertilizers. Phosphorus (P) deficiency is one of the primary constraints to bean production in the tropics. Experiments were conducted at Uyole and Mbimba in Southern highlands of Tanzania to investigate the genotypic variations of common beans in P utilization based on grain yield and yield components. Eight bean genotypes were tested at 0, 30 and 60 kg P ha -1 as Triple Super Phosphate. A split plot in a Randomized Complete Block Design was used for arrangements of treatments. Data analysis was performed using GENSTAT statistical analysis package Discovery Edition 4. Significant differences in pods/plant, seeds per pod, 100-seed weight and grain yield among genotypes were observed. Genotype GD 4032 performed better than other genotypes at all P applications and their response to P addition was positively significant, suggesting the vital role of P in grain yield. Genotype GD 4032 could be used to improve the productivity, reduce P requirements and making bean production more sustainable.
Role of sorghum genotype in the interaction with the parasitic weed striga hermonthica
(Sokoine University of Agriculture, 2005) Hermonthica Striga
Rodenburg, J., 2005. The role of sorghum genotype in the interaction with the parasitic weed Striga hermonthica. PhD thesis, Wageningcn University, Wagcningen, The Netherlands, 138 pp. with English, French and Dutch summaries. This thesis presents a study on the interaction between the parasitic weed Striga (S. hermonthica [Del.] Bcnth.) and the cereal crop sorghum (5. bicolor [L. | Moench). Its main objective was to find suitable measures for the selection of breeding material (crop genotypes) with superior levels of resistance or superior levels of tolerance to Striga. To meet this objective the physiological background of tolerance, the relation between Striga infestation, infection and yield loss and the effect of host genotype on Striga parasitism and reproduction were studied. These host-parasite interactions were studied with 4-10 different sorghum genotypes differing in level and mechanism of defence against Striga. Field experiments carried out in Mali were used for yield assessments and development and validation of selection measures. Through pot and agar-gel experiments, aboveground resistance measures were validated with observations on belowground stages. Pot experimentation was also used to create infection response curves and to measure photosynthesis and chlorophyll fluorescence to develop tolerance measures. Striga parasitism and reproduction, and the detrimental effect of Striga on crop yield can significantly be reduced through crop genotype choice. Maximum aboveground Striga number is a reliable selection measure for resistance. Striga flowerstalk dry weight can be used to identify genotypes that reduce Striga reproduction. The maximum relative yield loss is a suitable selection measure for tolerance in susceptible genotypes, while for more resistant genotypes the relative yield loss per Striga infection seems more appropriate. For these tolerance measures, yield assessment of nearby uninfected controls is indispensable. Chlorophyll fluorescence, more precisely photochemical quenching and electron transport rate, may enable screening for tolerance without this requirement.
Evaluation of common bean (Phaseolus vulgaris) genotypes for resistance to root rot disease caused by pythium aphanidermatum and pythium splendens under screen house conditions
(Journal of Natural Sciences Research, 2016) Binagwa, Papias H.; Bonsi, Conrad K.; Msolla, Susan N.
The most important economic species of the genus Phaseolus is the common beans (Phaseolus vulgaris L.) which is widely cultivated and arguably the most significant leguminous for direct human consumption. It is an important source of dietary protein, calories, dietary fibres and minerals particularly iron and zinc. Root rot disease caused by Pythium pathogen is one of the major production constraint in bean growing areas within East Africa. In Tanzania, control measures used by farmers are fungicidal seed treatments which are less effective and not environmentally friendly, soil drainage and crop rotation which are not sustainable in the disease management. This study focused on the evaluation and selection of promising common bean genotypes for resistance to Pythium root rot disease from 100 bean genotypes sourced from Tanzania, CIAT and Andean Diversity Panel (ADP). Inoculum of Pythium aphanidermatum and Pythium splendens were used for challenging the beans genotypes under controlled environment. Experiment was set by randomized completely block design (RCBD) with three replications. Disease severity was assessed based on 1-9 scale; 1 being non-pathogenic and 9 being highly pathogenic. The response of common bean genotypes to P. aphanidermatum and P. splendens and their interactions were statistically different (P<0.0001). Two bean genotypes ADP-014 and ADP-080 showed promising trait of resistance, 38 genotypes showed moderate resistant trait and 57 were susceptible to Pythium root rot disease.
Effect of tillage and weed control practices on weed density, cassava growth and yield at Mkuranga district, Tanzania
(East African Journal of Science, Technology and Innovation, 2023-09-14) Leonard, J. A.; Kudra, A. B.; Tryphone, G. M.
Poor and improper weeding in cassava production has been reported to cause cassava yield losses ranging from 40% to 90%. A study was carried out in 2019/2020 planting season at Kiimbwanindi village, Mkuranga, Tanzania to identify common weeds available in the selected cassava field and then the effect of different integrated weed control options was studied. Till only and till + Ridge, pre-emergence herbicides (Primagram Gold a.i 290 g/L S-metolachlor + 370 g/L atrazine and Oxfen a.i Oxyfluorfen 24% EC), post emergence herbicides (Force up a.i 480 g/L of Glyphosate-Isopropylamine salt) and back pack weeder with modified tines were tested on Cassava variety Kiroba in a factorial experiment arranged in a randomized complete block design (RCBD) replicated three times. Data on weed species, weed density, cassava height, girth and fresh root yield and soil were collected. By using Thomas methodology, perennial weeds Cyperus rotundus, Reissantia sp, Mucuna pruriens and Commelina benghalensis found to be the mostly and abundantly occurred weed species. The combination of tillage practices and pre-emergence herbicides application increased number of days’ weeds took to reemerge. The integrated weed control options significantly affected cassava fresh root weight and biomass, p = 0.019 and p = 0.026, respectively. The correlation analysis showed a non-significant positive relationship between cassava stem height and cassava fresh root weight (r = 0.389, p > 0.05), and cassava stem girth and cassava fresh root weight (r = 0.055, p > 0.05). The study concluded that, the combination of till + ridges, application of pre-emergence herbicide (S-metolachlor + atrazine) and post emergence herbicides (glyphosate) can effectively control weeds and provided favorable environment for cassava growth and root formation as compared to other treatment options.
Evaluating limitations of agroecological practices and stakeholders’ response: a case of Uluguru mountains landscape in Morogoro municipality, Tanzania
(East African Journal of Science, Technology and Innovation, 2023-09-14) Trypnone, G. M.; Pastory, S. T.
In Sub-Saharan Africa, conventional farming is associated with intensive use of synthetic chemicals and inputs to maximize agricultural productivity. This is done at the expense of sustainable agroecologically based production systems. This objective was to describe limitations of agroecological practices and stakeholders’ response along Mountain Uluguru. The area has been vulnerable to unregulated land degradation aggravated by soil erosion largely due to unsuitable agricultural practices. The data were collected through questionnaires and in-depth interviews from 72 respondents who were purposively selected. Both qualitative and quantitative data were analysed using content analysis and statistical software respectively. Farmers undertake agriculture to increase production so as to meet food needs (44.8%) and employment opportunities (55.2%). About 41.7% of farmers who had land with secure tenure grew fruit and non-fruit trees on their farms or homesteads, 11.7% rented the farming land temporarily from owners through informal arrangements and the rest squatted on public land for cultivation of vegetables. From SWOT analysis, agroforestry is threatened by unregulated agricultural activities (18.6%) and overuse of forest resources unsustainably (7.0%). The agroecology training is not coordinated and supported by government agencies, which have authority to inform the policy makers about insecure land tenure and unavailability of organic inputs that would increase farmers’ livelihoods. Agro-soil erosion control and conservation agriculture measures are essential features of agroecology training, but some farmers were not aware of them and those who are aware do not adopt them effectively. The study concludes that, without the government acknowledgement of agro-ecology and its associated contributions there will always be weak institutional coordination among stakeholders required to regulate, promote and support agro-ecology practices to create a balance of conserved environment, protected ecology and enhanced farmers’ livelihoods. This is because there is no clear national guidelines and support (financial and technical) addressing the challenges facing agro-ecology practice yet.
AMMI analysis for stability and genotype by environment interaction on common bean (Phaseolus vulgaris L.) genotypes in Mbeya region, Tanzania
(Current Journal of Applied Science and Technology, 2022-08-13) Muhamba, George Tryphone; Bilaro, Atugonza Luta
A significant Genotype by Environment Interaction (GEI) makes selection of stable genotypes difficult. This study was conducted to establish the effect of GEI on yield of Common bean genotypes and reduce complaints on the under performances. Eighteen (18) Common bean genotypes were assessed for variation in gene expression linked to yield and yield predictors on three different districts in Mbeya region (Mbarali, Mbozi and Mbeya districts). Regression, pooled ANOVA and AMMI biplot models were used to evaluate the data. Variety performance showed significant variations in yield between the districts. A similar scenario was observed in regard to yield predictors. Regression analysis showed that in Mbarali 50% was the significant yield predictor (P = 0.027) while pods/ plant was the trait mostly linked to yield in Mbozi. (GEI) analysis using the AMMI model revealed that best variety performance by location based on yield. Interaction principle component (IPC1) was highly significant (P = 0.0001) and contributed about 69.1% of GEI variation. The genotypes SER 83 and RCB 266 where highly adaptable in Mbarali site. The genotypes SER 45 and KG 521 showed specific interaction with the environment of Mbozi district. A total of five genotypes proved to be superior in Mbeya district. The most adapted stable variety with highest grand mean yield across all three mega environments was RCB233 (IPC1= 0.07, yield = 1073 t/ha). The environment in Mbarali was found to be most predictable for evaluation of Common bean genotypes.
Identification of potential seed storage protein responsible for bruchid resistance in common bean landraces from Tanzania and Malawi
(African Journal of Biotechnology, 2022-01) Maro, Caroline Ng’homange; Massawe, Deogracious Protas; Tryphone ,George Muhamba; Myers, James Robert; Davis, Joel William; Kusolwa, Paul Mbogo
Bean bruchids are among the most devastating insect pests of common bean that can inflict huge losses in storage. To identify potential resistance to these pests, screening was performed at Sokoine University of Agriculture. Two resistant landraces were identified, viz Kalubungula and KK25. Recombinant inbred (RI) KSy, KSw and ML populations were created from crosses between Soya × Kalubungula, Soworo × Kalubungula and Nagaga × KK25, respectively. Seed storage proteins were characterized and sequenced in RI population progenies to determine if phenotypic resistance was associated with α-amylase inhibitor – phytohemagglutinin – arcelin (APA) storage proteins. We found no association between the seed storage proteins observed in Kalubungula and its recombinant inbred lines with an APA protein. KK25 and its progenies had Arcelin-5, Leucoagglutinin, Erythroagglutinin and a hypothetical seed storage protein that conditions antibiosis effects as a resistance mechanism. The hypothetical seed storage protein observed in these lines may contribute to enhanced resistance.
Microsatellite analysis of common bean (Phaseolus vulgaris L.) genotypes in Tanzania for diversity in seed iron and zinc micronutrients
(Greener Journal of Plant breeding and Crop Science, 2023-02-15) Yanda, Focus Edson; Tryphone, George Muhamba
Common bean (Phaseolus vulgaris L.) grain has big dietary role in supplying protein, energy, vitamins, dietary fibre and micronutrients for millions of people worldwide. In Tanzania, reports have shown existence of Fe and Zn micronutrient variabilities among the common bean genotypes. Eighty-four (84) genotypes were collected to study such variability by seed biochemical and leaf molecular marker analysis. The analyses revealed significant (p < 0.001) genetic variability for seed Zn and Fe nutrient contents. Highest seed Fe content was 118 ppm for genotype Kashiransoni and for seed Zn was 51.81 ppm for Imponzo 5 genotype (both were collected from NPGRC). With seven (7) SSR primers associated with Fe and Zn traits, genetic diversity was evaluated. A marker BM154 scored PIC value 0.967 mean while marker BM160 had a lowest PIC score of 0.899. Using an estimated genetic similarity value, two main clusters with sub clusters in the dendrogram were developed. To corroborate the UPGMA analysis results, a Principal Coordinate Analysis (PCoA) was performed and displayed outputs into scattered plot presentation. For Fe micronutrient improvement purposes, Inula was proposed to be crossed with Kashiransoni while Roba with Imponzo 5 for Zn micronutrient improvement. Selection was based on both concentrations of nutrients for each genotype and their genetic similarity distances.
The effect of potyvirus resistance loci from the maize inbred line Oh1VI on development of maize lethal necrosis (MLN)
(Greener Journal of Agricultural Sciences, 2021-07-31) Bulegeya, Victoria B.; Jones, Mark W.; Muhamba, Tryphone G.; Das, Biswanath; Thomison, Peter R.; Francis, David M.; Redinbaugh, Margaret. G.
Maize lethal necrosis (MLN), a viral disease currently affecting corn in East and Central Africa is caused by a combined infection of Maize chlorotic mottle virus (MCMV) and any maize infecting potyvirus. Most of African maize germplasm is susceptible to the disease and there are no known sources of resistance. Recombinant inbred lines (RIL) derived from Oh1VI, a line known for multi-virus resistance with different QTL for potyvirus resistance on chromosome 3, 6 and 10 were selected and screened against MLN under artificial inoculation and natural infestation. Differences were observed among genotypes and QTL groups at P=0.05 in all experiments except under field inoculation. Genotypes with QTL combination of 3, 6 and 10 had at least 20% reduction in MLN symptoms compared to a susceptible check. These results provide useful baseline information on utilization of potyvirus resistance genes for MLN resistance and control in Sub Saharan Africa.
Effects of pre-harvest application of hexanal formulation on losses and quality of tomato (Solanum lycopersicum Mill)
(Tanzania Journal of Agricultural Sciences, 2020) Jaspa, S; Msogoya, T.; Tryphone, G.; Mtui, H .D.; Baltazari, A.; Kudra, A.; Mwatawala. M. W.
The study was conducted to determine the effects of field application of enhanced freshness formulation (EFF) on pre-harvest losses and tomato quality. The parameters assessed include pest defects on fruits, marketable and percentage non-marketable fruit, fruit firmness, and fruit weight. Three popular open pollinated varieties grown in Tanzania namely, Mwanga, Rio Grande, and Tanya were used. The experiment was laid out as Completely Randomized Design in a 4 x 4 x 3 factorial arrangement. Three factors, EFF concentrations, time of EFF application prior to the harvest, and tomato variety were evaluated. EFF concentrations of 0.01, 0.02, 0.04% m/v were tested. Untreated plots were included as control. The time of application was 7, 14, 21, and 28 days prior to the harvest. The results showed that pre-harvest application of EFF at 0.01 percent reduced percent non-marketable tomato fruit of Mwanga, Rio Grande, and Tanya cultivars by 28.99, 26.98 and 37.17 percent, respectively compared with the control. Moreover, pest defects were reduced by 29.45, 24.51, and 27.45 percent for Mwanga, Rio Grande, and Tanya, respectively over the control. Furthermore, fruit firmness was increased by 7.69 N/mm2, 6.33 N/mm2 and 5.98 N/mm2 compared with the control for tomato cv. Mwanga, Rio Grande, and Tanya, respectively
Inheritance of Angular Leaf Spot [Phaeoisariopsis griseola (Sacc.) Ferr] Resistance in Common Bean (Phaseolus vulgaris L.) Population Developed from Kablanketi Mexico 54
(Journal of Agricultural Science and Technology, 2012-07-20) Tryphone, George Muhamba; Chilagane, Luseko Amos; Kusolwa, Paul Mbogo; Nchimbi-Msolla, Susan
The genetic resistance to angular leaf spot (ALS) caused by Phaeoisariopsis griseola in the common bean cultivar Mexico 54 was investigated on disease reactions in parental, F1, F2 and backcross generations derived from crosses between a resistant cultivar Mexico 54 and a susceptible cultivar Kablanketi under screen house conditions. The heritability (h2) estimate was as high as 0.719 indicating a successful transfer of ALS resistance among progenies and thus selection can be performed in early generation. High heritability coupled with high expected genetic advance of 39.5% is considered to be more useful in predicting the outcome of selecting the best individuals. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in common bean. Based on the resistance of the F2, and the backcross generation to the resistant parent, a 3 resistant: 1 susceptible segregation ratio in the F2 and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent was obtained implying that resistance to the isolate of Phaeoisariopsis griseola is governed by a single, dominant gene.

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