Articles, Conference and Workshop Papers Collection
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Item Characterization of selected rice genotypes from eastern and southern Africa tolerant to salinity at seedling stage(Sokoine University of Agriculture, 2024-05)Soil salinity stands as a prominent abiotic stress significantly impacting rice production and food security within sub-Saharan Africa. A promising strategy to mitigate this challenge involves the development and deployment of salinity-tolerant rice varieties. The objective of this study was to identify salinity-tolerant rice genotypes suitable for integration into breeding programs, offering a viable solution to salinity-affected soils in Eastern and Southern African rice-growing areas. The investigation focused on both phenotypic and genotypic characterizations of selected rice genotypes at the seedling stage, coupled with the identification of salinity tolerance- associated quantitative trait loci (QTLs). This research focused on analyzing a collection of 206 rice genotypes obtained from Tanzanian farmers' fields, along with other genotypes from Eastern and Southern Africa. genotypes were then subjected to phenotypic screening under a salinity level of 12 dS/m, utilizing a hydroponic system and following the established IRRI protocol. From this initial pool, 13 genotypes were carefully selected based on their SES scores to undergo more detailed evaluation of their growth and physiological characteristics. To identify the presence of the Saltol allele, a widely recognized QTL associated with salinity tolerance, genotypic analysis was performed using 1k- RiCA SNP markers. Phenotypic screening revealed salinity's adverse effects on various growth parameters, particularly on root and shoot dry weights, indicative of osmotic imbalance. Correlation analysis identified sodium concentration, sodium-to-potassium ratio, and canopy temperature as strong indicators of salinity tolerance in rice genotypes. These variables hold as potential physiological markers for salinity tolerance screening in breeding programs. Principal Component Analysis (PCA) was employed to identify key variables for salinity tolerance, revealing potassium ratio, root dry weight, shoot dry weight, shoot length, and survival as significant contributors. Based on PCA results, genotypes were classified into tolerant, moderately tolerant, and sensitive categories. Six moderately tolerant genotypes (Intsindagira Bigega, K5, SATO 1, Sukari, Terembele (LL 29), and ZX 117) exhibited promising phenotypic tolerance, making them potential candidates for enhancing salinity tolerance in rice varieties. Concurrently, Genotypic evaluation at the seedling stage provided insights into the expression of salinity-tolerant traits among the rice genotypes. Remarkably, 36 rice genotypes were found to possess the Saltol allele, recognized for its role in conferring salinity tolerance. some Saltol-possessing genotypes exhibited inadequate performance under salinity stress conditions. Interestingly, 16 genotypes lacking the Saltol allele demonstrated salinity tolerance, suggesting the presence of other genetic factors (QTLs) contributing to this trait beyond Saltol. Additionally, the geographical distribution of Saltol-possessing genotypes within Tanzania revealed variations across different Agro-ecological zones. Notably, the Coastal Zone exhibited a higher proportion of phenotypically tolerant genotypes compared to other zones, suggesting local farmers' continuous selection pressure as a possible contributing factor. These findings highlight the potential for integrating diverse salinity-tolerant rice genotypes, possessing various genetic mechanisms, into breeding programs. This approach could lead to the development of novel rice varieties capable of thriving under salinity stress conditions.Item Viability and genetic integrity of African eggplant (Solanum spp.)seeds during natural ageing under cold dry storage(Sokoine University of Agriculture, 2024) Jonas Nickas; Sognigbé N'Danikou; Abdul J. Shango; Newton KilasiSeed deterioration occurs gradually during long-term seed storage. Viability, vigour, and genetic integrity of African eggplant seeds were assessed under natural ageing during genebank storage. The percentage of tail DNA before and after seed imbibition was used to account for genotoxicity and DNA repair during cold dry storage at 10 °C using the comet assay. After 2, 5, and 12 years of storage in the genebank, a reduction of seed viability was observed in all studied African eggplant genotypes. However, seed viability was more significantly reduced in seed lots that had been stored for a longer period in the genebank (p < 0.05). Overall, higher viability loss was recorded in seeds regenerated 12 years before (p < 0.05). The molecular analysis by comet assay showed significant DNA damage during natural aging under genebank conditions, accompanied by important loss of viability and germination energy in older seeds translated into low DNA repair after seed imbibition. The seed lots which had better initial quality were able to maintain higher viability during genebank storage. The findings inform on the storage behaviour of African eggplant genotypes and are relevant for the proper handling of seed lots in genebanks. They are also relevant for future studies on seed longevity prediction in African eggplant.Item Effects of soil pH levels on iron and zinc concentrations of common bean (Phaseolus vulgaris L.) genotypes(African Journal of Agricultural Research, 2024-07) Magomere, Kinguye Masamaki; Nchimbi-Msolla, Susan; Tryphone, George MuhambaPlants grown in acid soils experience a variety of stresses which include aluminium, hydrogen and/or manganese toxicity, as well as nutrient deficiencies of calcium and magnesium. A study was carried out to determine the influence of soil pH levels on iron and zinc concentrations in leaves and seeds of twenty-five common bean genotypes. Plastic cups trial was carried out in the screen house to determine the actual amount of quick lime Ca(OH)2 required to reach a targeted soil pH level. In each pot, 4 kg soil was amended with Ca(OH)2 to obtain the target soil pH levels of 5.3, 5.5, 6.5 and 7.5. The experimental design followed a randomized complete block design in a split plot arrangement with three replications per treatment. The pH levels were treated as main factor and genotypes as sub plot. Data collected include leaf iron concentration, seed iron concentration, leaf zinc concentration, and seed zinc concentration and analysis of variance was performed for all data using GenStat statistical package 15th edition. The result demonstrated that soil pH affects absorption of micronutrients directly or indirectly by affecting the nutrients availability to common bean plants.Item Unexplored agronomic, socioeconomic and policy domains for sustainable cotton production on small landholdings: a systematic review(Frontiers in Agronomy, 2023-11-20) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira KisetuCotton productivity continues to be disputed, despite rapid advancements and widespread technologies. These uncertainties remain to be critically addressed in a broad spectrum focusing on domains at the global level. Therefore, this systematic review provides an overview of the existing advancements in knowledge, skills, and technologies for sustainable cotton production on small landholdings. Specifically, the areas of the cotton chain examined are threefold: - (1) Explore disguised agronomic practices to be endowed for sustainable cotton production on small landholdings; (2) Explore socioeconomic settings based on their disparities in contributing to sustainable cotton production on small landholdings; and (3) Explore existing and feasible institutional policies to be enforced for sustainable cotton production on small landholdings. This review shows that worldwide cotton production involves conventional and organic systems, at the expense of the traditional system. Heavy uses of nitrogenous fertilizers and pesticides are the common practices in conventional systems, with some adoptions of precision agriculture practices, and genetically modified varieties. Rotation and intercropping with early-maturing food crops are also identified viable options to improve farmers’ attitudes toward adopting cotton- producing technologies. In socioeconomics, farmers’ livelihoods are improved by income generation from sales of cotton and labour in the cotton industry. Gender equity in the cotton industry prioritizes females over males, as females display a group with a higher level of technology adoption. Generally, clear institutional policies governing the cotton industry are globally paucity. Furthermore, efforts to sensitize sustainable cotton production are still highly questionable and challenged by the superseding climate changes.Item Effects of sowing dates and phosphorus levels on cotton growth and yield: soil analysis and implications(Frontiers in Sustainable Food Systems, 2023-11-20) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira KisetuThis study assessed the effects of sowing dates and phosphorus levels on cotton performance in Chato-Msilale village in Chato District, Tanzania. The soil analysis revealed that field exhibited slightly acidic soil with normal electrical conductivity but suffered from severe deficiencies in total nitrogen and organic carbon. The same field presents common issue of low cation exchange capacity, indicating limited nutrient-holding capacity. Furthermore, both fields displayed very low levels of total nitrogen (<0.1%), signaling a nitrogen deficiency. Available phosphorus was rated as medium (16.8 mg kg−1 soil). Trace elements fluctuated and could be managed based on specific crop requirements. The factors at different levels were: (1) sowing dates – (i) 25th November 2022, (ii) 15th December 2022, and (iii) 4th January 2023; and (2) Phosphorus levels – (i) control, (ii) 20 kg P ha−1, (iii) 40 kg P ha−1, and (iv) 60 kg P ha−1. Regarding cotton growth and yield, sowing dates significantly (p < 0.001) influenced plant height, gin turnout, lint yield, number of bolls per plant, and boll weight while phosphorus levels did not exhibit significant effects. Earlier sowing dates resulted in higher yields, albeit with variations in yield components. Interactions showed that growth and yields were only numerically higher in the middle sowing date at higher levels of phosphorus applied. Overall, these insights offer valuable guidance for optimizing cotton cultivation in Chato District, emphasizing the importance of selecting appropriate sowing dates for improved yields.Item Studies on the influence of altitude on abundance of fall armyworm (spodoptera frugiperda (Je Smith)) (lepidoptera: noctuidae) in Tanzania(Society for Science and Education, 2023-08-25) Mbemba, Kiva F.; Rwegasira, Gration M.; Tryphone, George M.Fall armyworm (FAW) (Spodoptera frugiperda) is one of the most devastating polyphagous field crop pests in many parts of the world, including Tanzania. Influence of altitude on the abundance of S. frugiperda was studies by using Pheromone (Frugilure S. frugiperda, Chemtica international, S.A) embedded cup traps. The study was conducted along sites of Mt. Uluguru slopes including; SUA (525 masl), Mlali (579 masl), Mgeta (1050 masl) and Nyandira (1691 masl) located in Morogoro Region, Tanzania. A total of 16 cup traps (four at each site equidistantly arranged at 100 m apart) were used. Weather data were recorded using Hygrocron i-button hung on a tree at equidistant from the four traps. Data on S. frugiperda counts and weather variables were recorded weekly for duration of six months from January to June 2020. Results showed that S. frugiperda was abundantly recorded across he tested altitude albeit at varied abundance. There was significant difference (p < 0.001) among altitude on S. frugiperda abundance, whereby at low altitude, S. frugiperda abundance was high compared to medium and high altitude. Rainfall had positive correlation on S. frugiperda abundance (r = 0.16, r = 0.04) for SUA and Mlali and negative correlation (r = -0.44) and (r = -0.03) for Mgeta and Nyandira. Temperature had positive correlation (r = 0.21) on S. frugiperda abundance at Nyandira while SUA (r = -0.03), Mlali (r = -0.35) and Mgeta (r = -0.28) had negative correlation. Relative humidity for all four locations showed negative correlation with S. frugiperda abundance. Thus, appropriate and effective management practices of S. frugiperda should be considered throughout maize production areas and across crop production seasons regardless of the altitude.Item Genetic parameters estimate of iron and zinc nutrients in common bean genotypes(African Journal of Agricultural Research, 2024-06) Magomere, Kinguye Masamaki; Nchimbi-Msolla, Susan; Tryphone, George MuhambaThere is need to know the heritability of different traits for the effective selection of parents for future breeding activities. A study was carried out to determine heritability of iron and zinc in common bean. Crosses were made with each donor and recipient parents to obtain four different types of crosses. Part of the F1 seed from each cross was sown in the screen house to produce F2 seeds and also backcrossed to both parents. Heritability was estimated using backcross method for high broad sense heritability and narrow-sense heritability. Broad sense heritability for progenies of NUA 11 × Zawadi (56%), NUA 11 × Pesa (76%), NUA 17 × Zawadi (57%) and NUA 17 × Pesa (59%) were obtained. Narrow sense heritability estimates for progenies of NUA 11×Zawadi, NUA 11 × Pesa, NUA 17 ×Zawadi and NUA 17 × Pesa were 65%, 71%, 79% and 63%, respectively. Genetic advance (GA) values for NUA 17 × Zawadi, NUA 11 × Pesa, NUA 17 × Pesa and NUA 11 × Zawadi was 35, 12.3, 3.5 and 1%, respectively. This study demonstrates that there is a potential for improvement of concentration of iron and zinc in common bean genotypes. Therefore, selection of a superior genotype on the basis of its phenotypic performance, heritability of traits could be well exploited.Item 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) Tryphone, 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.Item Impact of sowing date and level of phosphorus application on economic returns in cotton(Frontiers in Plant Science, 2024-06-12) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira KisetuThis study explored the economic dynamics of cotton (Gossypium hirsutum L.) production in Msilale village, Chato District, Tanzania. The experiment utilized a factorial design with sowing dates on November 25th, December 15th, and January 4th, and phosphorus levels at 0, 20, 40, and 60 kg P ha-1, replicated three times. Results indicated significantly higher cotton yields (6.1 t ha-1 and 6.3 t ha-1) for November and December sowings compared to January (3.8 t ha-1). This is a 61% and 66% increase in cotton yields for November and December sowings, respectively relative to January sowing. Though not significant, 20 kg P ha-1 and 40 kg P ha-1 applications yielded 5.8 t ha-1 and 5.4 t ha-1, respectively, while 60 kg P ha-1 yielded 5.3 t ha-1. This is a 9.4% and 1.9% increase in cotton yields at 20 and 40 kg P ha-1, respectively relative to absolute control and 60 kg P ha-1 application. Economic analysis revealed that late sowing (January) had the lowest net profit (Tshs. 3,723,400 ≈ USD 1,486) and benefit-to-cost ratio (BCR) of 11.2. Early sowings recorded higher net profits (Tshs. 6,679,527 ≈ USD 2,666 and Tshs. 6,861,283 ≈ USD 2,738) and BCRs (18.4 and 18.8, respectively). This is a 79% (BCR = 64%) and 84% (BCR = 68) increase in net benefits from early sowings compared to late sowing. Applications of 20, 40, and 60 kg P ha-1 resulted in net benefits of Tshs. 5,452,572 ≈ USD 2,176 (BCR = 19.2), Tshs. 5,209,904 ≈ USD 2,079 (BCR = 15.1), and Tshs. 5,748,786 ≈ USD 2,294 (BCR = 14.1), respectively, with a significant (p = 0.017) BCR at 20 kg P ha-1 indicating cost-effectiveness. This is a 36% and 7.1% economic benefit at 20 and 40 kg P ha-1, respectively compared to 60 kg P ha-1 application. Optimizing sowing dates and P levels can boost economic returns in cotton production and promote sustainability.Item Improving cotton fiber quality through strategic sowing: implications for phosphorus management from experiments in Chato district, Tanzania(Journal of Natural Fibers, 2024) Tlatlaa, Jacob Shauri; Tryphone, George Muhamba; Nassary, Eliakira KisetuThis study was conducted in Msilale Village, Chato District in Tanzania, to evaluate the influence of sowing dates and phosphorus levels on cotton fiber quality. The study was established according to a factorial trial, with varying sowing dates (25th November 2022, 15th December 2022 and 4th January 2023) and phosphorus levels (control, 20 kg P ha−1, 40 kg P ha−1, 60 kg P ha−1). Results revealed that early planting had a statistically signifi cant (p < .001) effect on fiber cotton quality, including spinning coefficient index, fiber length, fiber strength, uniformity index, short fiber content, and grade/color. Early sowing dates (25th November 2022 and 15th December 2022) consistently produced superior fiber quality, including spin ning coefficient index (156.5 and 148.4), moisture content of the fiber (7.8% and 7.7%), micronaire (3.5 μg/inch), upper half mean length (1.2 cm), unifor mity index (84.6% and 84.2%) and shorter fiber (6.8% and 7.0%) relative to late sowing (4th January 2023). Conversely, phosphorus levels did not sig nificantly (p > .05) impact these parameters within the tested range. This research underscores the critical role of selecting appropriate sowing dates for cotton cultivation to achieve better fiber quality.Item Effect of integrated weed control options on growth and yield of cassava at Kilosa district, Tanzania(Society for Science and Education, 2023-12-25) Leonard, Joseph Adonia; Laswai, Emmanuel Vicent; Kudra, Abdul B.; Tryphone, George M.Weeds are among of the major pest that hinders cassava growth and production. Also, weeds can host insect and disease pathogens, thus brings up difficulty in the growth of cassava. The effect of different weed control treatment combinations was studied at Ilonga village, Kilosa district during 2019/2020 planting season. 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. Combination of tillage practices and pre-emergence herbicides application increased number of days weeds took to re-emerge. The correlation analysis showed a highly significant strong positive relationship, r = 0.925, p < 0.001 and r = 0.781, p < 0.05 between cassava stem height and cassava fresh root weight, and cassava stem girth and cassava fresh root weight, respectively. Weed control combinations did not significantly affect the cassava fresh root weight, p = 0.514 and cassava biomass p = 0.732. Also weed control combinations did not significantly affect soil quality. The combination of till + ridges, application of S-metolachlor + atrazine herbicides and glyphosate provided favorable environment for cassava growth and root formation as compared to other treatment combinations. Therefore, it is recommended as a best option for controlling weeds in cassava production system.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.Item 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.