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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.
Agronomic package for maize production in semi-coral environment of Pemba, Zanzibar
(AJOL, 2017) Msuya, D. G.; Ali, O. M.
Maize is an important food crop in the semi-coral area of Pemba Island. Production has however never met demand due to very poor yields, about 1.0 t/ha in the area. An experiment was conducted to establish agronomic recommendations for increasing the maize crop productivity. Three improved varieties (Staha, Situka, TMV-1) were tested against variety JKU, a locally grown type in the area. Treatments included four nitrogen rates (23, 46, 70 and 90 kgN/ha) and three plant densities (44,444; 53,333 and 66,666 plants/ha). The treatment sources of variation (varieties, densities and fertilizer rates) had significant effects on growth and yield of the maize crop. Use of variety Staha significantly (P < 0.05) improved yield compared to the local variety (JKU) and the other tested varieties. Yield difference between best performing and least performing variety was about 69%. Through optimized spacing yield difference as much as 32.9% was achieved while through improved Nitrogen fertility yield was increased by as much as 28.8%. The use of variety Staha, grown at a spacing of 75 cm × 20 cm giving a plant population of 66,666 ha-1; and the use of nitrogen at 70 kgN/ha is recommended for best maize yields in the area. The best practice is to optimize all the three factors in combination.
The alarming spread of banana Xanthomonas wilt in eastern Democratic Republic of Congo and its impact on food security and income
(Global Science Books, Ltd, 2010) Dowiya, N. B.; Blomme, G.; Dheda, D. B.; Rweyemamu, C.; Velly, D.; Vigheri, N; Milambo, A.; Eden-Green, S.; Karamura, E.; Maerere, A.
Xanthomonas wilt of banana (caused by Xanthomonas campestris pv. musacearum) is an unforgiving disease. Rather than merely reducing yield, as do many diseases, it causes the fruit to ripen prematurely and rot. Since 2001, the disease has spread to several countries in east and central Africa. It was first observed in the territory of Masisi, 72 km northwest from Goma in North Kivu Province, DR-Congo in 2001. During a survey conducted in May 2006 in the framework of the USAID-funded Crop Crisis Control Project (C3P), Xanthomonas wilt was also observed in the Mahagi and Irumu territories, Oriental province (north-eastern DR-Congo close to the border with Uganda) and in the region between Beni (north Kivu, DR-Congo) and Bundibugyo (western Uganda). Here the disease had most likely spread from infected areas across the border in Uganda. It had also spread over an area with a 50 km radius in Kitchanga, Masisi, North Kivu. A survey conducted in May 2008 in the framework of the Belgian-funded project CIALCA, reported that Xanthomonas wilt had entered South Kivu (Minova, Kalehe territory). In north Kivu the disease is currently present in the districts of Masisi, Rutshuru, Beni, Nyiragongo and Walikale and in Oriental province the disease is currently present in the Mahagi and Irumu districts. The disease has thus spread over an area more than 600 km long (north-south axis). At least two million people in eastern DR-Congo are impacted by this disease which threatens food security and farm income. The most important means of dissemination are infected planting materials, contaminated farm tools and insect vector transmission. Extension efforts to contain the spread of Xanthomonas wilt are hampered by insecurity and inaccessibility of large parts of eastern DR-Congo.
Altered response to biotic and abiotic stress in tissue culture-induced off-type plants of East African Highland Banana (Musa AAA East Africa)
(Asian Network for Scientific Information, 2008) Msogoya, T. J.; Grout, B. W.
This study was conducted to investigate black sigatoka disease and drought stress responses of off• type plants derived from shoot-tip micropropagation of East African highland banana (Musa AAA East Africa) landrace Uganda. Results showed that the off-type plants were more (p<0.05) tolerant to black sigatoka disease with the infection index of 17 .5% compared to 30.1 and 22.8% of the micropropagation (Ml') derived phenotypically normal plants and Conventional Propagation (CP) derived plants with no tissue culture history in their ancestry, respectively. On the contrary, the off-type plants were more (p<0.05) vulnerable to water stress with leaf senescence of 87.7% at soil water deficit of 630 millibars. The leaf senescence of the 1v1.P and CP derived plants at the same soil moisture deficit was 79.5 and 66.7%, respectively. During this stress period each off-type plant produced one sucker, while the true-to-type plants were unable to do so. Leaf structural analysis revealed that the off-type plants had higher (p<0.05) stomatal density of 16.0 mm-2 of the upper leaf surface. Conversely, the MP and CP derived plants had each 12.3 and 11.0 stomata mm ? of the leaf upper surface. Similarly, the off-type plant leaves were more hydrophobic with higher (p<0.05) epicuticular waxiness of 684.6 μg cm ". The epicuticular wax content of the 1v1.P and CP derived plant leaves was as low as 646.2 and 647.7 μg cm ", respectively. The water stressed off-type plant leaves exhibited higher (p<0.05) membrane damage with ion leakage of 168.2 μS cm" compared to 139.7 and 136.8 μS cm" of the 1v1.P and CP derived plants. Moreover, the water stressed leaves of the off-type plants had enhanced total antioxidant activity of 5.17 M trolox equivalent per milligram proteins, whereas the total antioxidant activity of the MP and CP derived plant leaves was as low as 3. 76 and 3.67 M trolox equivalent per milligram proteins, respectively.
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.
Assessment of the effect of pruning systems on plant developmental cycle-yield and quality of selected indeterminate tomato lines
(Acta Hort. 1007, ISHS, 2013) Mbonihankuye, C.; Kusolwa, P.; Msogoya, T. J.
Preliminary evaluations have shown that indeterminate new tomato breeding lines produce high yields of large fruits. Pruning systems have been reported to regulate tomato fruit size and overall yield performance. A study to evaluate the effect of pruning levels (non pruning, single stem, two stems and three stems) on plant developmental cycle, yield, and quality of five indeterminate tomato breeding lines and one commercial cultivar was conducted from November 2009 to March 2010 at the Horticulture Unit of Sokoine University of Agriculture, Morogoro, Tanzania. Results showed that two stem pruned plants gave the highest number of marketable fruits per plant. The highest number of non marketable tomato fruits per hectare was observed in unpruned plants. Tomato lines differed in their performance, with the longest period of harvesting, highest number of flowers flowers, highest percentage of fruit-set, the highest yield, high number of marketable fruits observed in lines P20-(03) and 186-2(06), which is probably a result of their genetic characteristic. It was concluded that, the large fruit size of the new tomato breeding lines can be reduced to meet consumer’s needs without reducing yield by two and three stem pruning in lines P20-03 and S186-2(07).
Assessment of the effects of water stress on seed yield of common bean genotypes
(African Journal of Agricultural Research, 2020) Claude Rubyogo, Jean; Mbiu, Julius Peter; Msolla, Susan Nchimbi; William, Magdalena N.
Drought stress is among the most important abiotic factors that contribute to the significant yield reduction of common bean (Phaseolus vulgaris L.). Due to unreliable and poor distribution of rainfall, drought tolerance has become the important train in common bean in bean growing areas. The objective of this study was to evaluate 16 common bean genotypes for drought tolerance under three moisture regimes and identify genotypes with specific traits that improved tolerance to drought that could be recommended for released and become useful parents in the breeding programs. The experiment was conducted in Maruku, Bukoba under screen- house. Based on the drought stress indices which includes drought tolerance index (DTI), Harvest Index (HI) SMC 162, DAB 602, SSIN 1128, DAB 378, DAB 362 and SMR 101 had performed better than other tested genotypes. Also, the results showed that genotypes DAB 582, SRC 59, DAB 602, SSIN 1240, SMC 24, SMR 101 and DAB 362 were drought tolerant with lower and high value of the DSI and YSI respectively. Therefore, the later genotypes can be used in the future breeding programs as the parent for drought tolerance and also can used as a new varieties by farmers.
Awareness and application of existing agroecological practices by small holder farmers in Mvomero and Masasi districts-Tanzania
(Canadian Center of Science and Education, 2020-12-15) Constantine, John; Sibuga, Kallunde P.; Shitindi, Mawazo J.; Hilberk, Angelika
A survey study was conducted to assess the level of awareness and application of existing agro-ecological practices by small holder farmers in Mvomero and Masasi districts in Tanzania. The selection of farmers to interview and the villages in the respective districts was based on their long history of producing cassava and maize. A structured questionnaire was used to identify the type of agro-ecological practices, agricultural information sources accessed by farmers, training on agro-ecological practices, type of crops grown in the study areas and kind of livestock kept. Results indicated that the most applied agro-ecological practices were diversification (80.5%), the use of farmer saved seeds (78.2%) followed by intercropping (72.9%) and lastly, agro-forestry (3.2%). The highest percentage of farmers (30.4%) reported to receive information on ecological organic agriculture from non-governmental organisations (NGOs) (SAT, SWISS AID), 27.5% were using own farming experience, 21% reported to receive the information from government extension officers, 13% from friends or neighbours, 4.3% from government institutions (SUA, Agricultural Training Institutes) and 3.6% received information from agricultural input suppliers. Generally, 50% of farmers had received training on agroecological practices indicating the level of awareness. Lack of knowledge among farmers was one of the key factors that hamper the wide application of agroecological practices. There was a need for farmer’s capacity building through training to enhance wider application of agroecological practices hence progressive agricultural production increase.
Banana (Musa spp. Colla) cropping systems, production constraints and cultivar preferences in eastern Democratic Republic of Congo
(Journal of Animal & Plant Sciences, 2009) Dowiya, N. B.; Rweyemamu, C. L.; Maerere, A. P.
Banana and plantain (Musa spp.) are important crops in the Democratic Republic of Congo (DRC) for food security and household income. However, yield has been decreasing to an average of 4.6 tons/ha currently, and the factors leading to the decline have not been fully determined. In the present study a diagnostic survey was conducted in the South Kivu (SK) and North Kivu (NK) regions of the country to determine the existing banana production constraints. Soil was sampled for analysis from 240 fields (30 samples/site) from 8 sites. The results indicated that apart from one site (Maboya, NK), soil fertility is not a limiting factor for banana production in the area. Planting materials used by farmers are exclusively suckers from existing crops and there is no institution producing clean planting materials in the area. Tillage using hand hoes for the purpose of growing common bean causes destruction of banana roots leading to poor nutrient uptake which contribute to low yield (3kg/bunch). Weed control is done by hand using hoes. Inadequate weeding and inappropriate desuckering practices increases competition between plants, leading to production of small bunches. In order of importance, the most important criteria for cultivar selection were flavour/taste, juice quality, resistance to disease and bunch size. Diseases including black Sigatoka, Fusarium wilt, Xanthomonas wilt, bunchy top virus, nematodes and weevils were identified as among the main causes of cultivar disappearance in eastern DRC. Although farmers have generally little knowledge on banana plantation management, they have good understanding on value addition through beer brewing. Hence farmers allocate an average of 50% of banana fields to wine producing cultivars. Cultivars from subgroup like AAA-Cavendish, AAA-Gros Michel, AAA-Ibota, AB-Ney poovan, AABKamaramasengi and ABB are well adopted for wine making. A total of twenty nine and thirty two banana accessions were found to be grown by farmers in SK and in NK, respectively. Based on similarity among these accessions using farmers’ criteria two clusters were identified consisting of wine/beer banana, and a combination of cooking, roasting and dessert types. The good market demand for plantains have motivated farmers in North-Kivu to allocate the largest part of their farms (25%) to French plantain Nguma (AAB) while in South Kivu the largest area (64.5%) is allocated to Nshikazi (AAA-EAHB) for beer production. Farmers’ mixed cropping system includes legumes, cereals, and multipurpose trees in the banana plantation or as hedgerows. Banana production can be improved in the study area using participatory research and development approach where smallholder farmers could evaluate appropriate technology introduced in the form of research. The key intervention measures are introduction of improved varieties with high yield and/or resistant to disease and sensitization on integrated pest management which could contribute into food security and poverty reduction.
Banana (Musa spp. Colla) cropping systems, production constraints and cultivar preferences in Eastern Democratic Republic of Congo
(2009-09-15) Dowiya, N .B.; Rweyemamu, C . l.; Maerere, A.P.
Banana and plantain (Musa spp.) are important crops in the Democratic Republic of Congo (DRC) for food security and household income. However, yield has been decreasing to an average of 4.6 tons/ha currently, and the factors leading to the decline have not been fully determined. In the present study a diagnostic survey was conducted in the South Kivu (SK) and North Kivu (NK) regions of the country to determine the existing banana production constraints. Soil was sampled for analysis from 240 fields (30 samples/site) from 8 sites. The results indicated that apart from one site (Maboya, NK), soil fertility is not a limiting factor for banana production in the area. Planting materials used by farmers are exclusively suckers from existing crops and there is no institution producing clean planting materials in the area. Tillage using hand hoes for the purpose of growing common bean causes destruction of banana roots leading to poor nutrient uptake which contribute to low yield (3kg/bunch). Weed control is done by hand using hoes. Inadequate weeding and inappropriate desuckering practices increases competition between plants, leading to production of small bunches. In order of importance, the most important criteria for cultivar selection were flavour/taste, juice quality, resistance to disease and bunch size. Diseases including black Sigatoka, Fusarium wilt, Xanthomonas wilt, bunchy top virus, nematodes and weevils were identified as among the main causes of cultivar disappearance in eastern DRC. Although farmers have generally little knowledge on banana plantation management, they have good understanding on value addition through beer brewing. Hence farmers allocate an average of 50% of banana fields to wine producing cultivars. Cultivars from subgroup like AAA-Cavendish, AAA-Gros Michel, AAA-Ibota, AB-Ney poovan, AABKamaramasengi and ABB are well adopted for wine making. A total of twenty nine and thirty two banana accessions were found to be grown by farmers in SK and in NK, respectively. Based on similarity among these accessions using farmers’ criteria two clusters were identified consisting of wine/beer banana, and a combination of cooking, roasting and dessert types. The good market demand for plantains have motivated farmers in North-Kivu to allocate the largest part of their farms (25%) to French plantain Nguma (AAB) while in South Kivu the largest area (64.5%) is allocated to Nshikazi (AAA-EAHB) for beer production. Farmers’ mixed cropping system includes legumes, cereals, and multipurpose trees in the banana plantation or as hedgerows. Banana production can be improved in the study area using participatory research and development approach where smallholder farmers could evaluate appropriate technology introduced in the form of research. The key intervention measures are introduction of improved varieties with high yield and/or resistant to disease and sensitization on integrated pest management which could contribute into food security and poverty reduction.
Biodiversity of fruit flies (Diptera, Tephritidae) in orchards in different agro-ecological zones of the Morogoro region, Tanzania
(Cirad/EDP Sciences, 2006) Mwatawala, Maulid W. M; De Meyer, Marc; Makundi, Rhodes H.; Maerere, Amon P
Introduction. Fruit flies (Diptera, Tephritidae) are among the major constraints in commercial horticulture in many African developing countries. Knowledge of the tephritid spectrum in any given area is a prerequisite for the development of an IPM program to alleviate the pest problem. We studied the fruit fly diversity in four main agro-ecological zones which are significant fruit-producing areas in the Morogoro Region, Tanzania. Materials and methods. Fruit fly diversity was investigated for one year (October 2004 – October 2005). Parapheromones, synthetic food attractant and protein-bait traps were used to trap the flies at the different locations in Morogoro region, Tanzania. One mixed orchard was selected at each of four locations representing the different agro-ecological zones of the region. Results. The recently intro- duced alien species, Bactrocera invadens, and three indigenous pest species, Ceratitis rosa, Dacus bivittatus and D. punctatifrons, were found at all the four sites, while Bactrocera cucurbitae, Ceratitis cosyra, Dacus chiwira and D. humeralis were found in three out of the four sites. The Sokoine University of Agriculture (SUA) Horticulture Unit and Mikese sites had the highest species diversity while the Mkindo and Nyandira sites had the lowest diversity. The between-habitats diversity (Beta diversity) was similar among the SUA, Mkindo and Mikese sites. Only the Nyandira site had a higher dissimilarity in comparison with the other three sites. Discussion. The most abundant species at low- and mid-elevation sites was Bactrocera invadens while, at high elevation, Ceratitis rosa was the dominant species. Protein-baited traps attracted the highest diversity of fruit flies in comparison with the more specific parapheromones. The synthetic food attractant (three-component lure) was less efficient compared with the protein bait. The large dissimilarity at the Nyan- dira site is probably due to the different types of host fruits found and grown in high altitude areas (mainly temperate fruits). Fruit fly species associated with these types of fruits, e.g., Ceratitis rubivora and Tri- rhithrum coffeae, were found only at this site.
Biodiversity of fruit flies (Diptera, Tephritidae) in orchards in different agro-ecological zones of the Morogoro region, Tanzania
(Fruits, 2006) Mwatawala, M. W.; De Meyer, M.; Makundi, Rhodes H.; Maerere, A. P.
Introduction. Fruit flies (Diptera, Tephritidae) are among the major constraints in commercial horticulture in many African developing countries. Knowledge of the tephritid spectrum in any given area is a prerequisite for the development of an IPM program to alleviate the pest problem. We studied the fruit fly diversity in four main agro-ecological zones which are significant fruit-producing areas in the Morogoro Region, Tanzania. Materials and methods. Fruit fly diversity was investigated for one year (October 2004 – October 2005). Parapheromones, synthetic food attractant and protein-bait traps were used to trap the flies at the different locations in Morogoro region, Tanzania. One mixed orchard was selected at each of four locations representing the different agro-ecological zones of the region. Results. The recently introduced alien species, Bactrocera invadens, and three indigenous pest species, Ceratitis rosa, Dacus bivittatus and D. punctatifrons, were found at all the four sites, while Bactrocera cucurbitae, Ceratitis cosyra, Dacus chiwira and D. humeralis were found in three out of the four sites. The Sokoine University of Agriculture (SUA) Horticulture Unit and Mikese sites had the highest species diversity while the Mkindo and Nyandira sites had the lowest diversity. The between-habitats diversity (Beta diversity) was similar among the SUA, Mkindo and Mikese sites. Only the Nyandira site had a higher dissimilarity in comparison with the other three sites. Discussion. The most abundant species at low- and mid-elevation sites was Bactrocera invadens while, at high elevation, Ceratitis rosa was the dominant species. Protein-baited traps attracted the highest diversity of fruit flies in comparison with the more specific parapheromones. The synthetic food attractant (three-component lure) was less efficient compared with the protein bait. The large dissimilarity at the Nyandira site is probably due to the different types of host fruits found and grown in high altitude areas (mainly temperate fruits). Fruit fly species associated with these types of fruits, e.g., Ceratitis rubivora and Trirhithrum coffeae, were found only at this site.
Cassava processing and dietary cyanide exposure in Tanzania
(Uppsala University, 1995) Mlingi, Nicholas L. V.
Mlingi, N.L.V. 1995. Cassava Processing and Dietary Cyanide Exposure in Tanzania. Acta Universitatis Upsaliensis, Comprehensive Summaries of Uppsala Dissertations from the Faculty of Medicine 571.69 pp. Uppsala. ISBN 91-554-3603-X. The relationship between dietary cyanide (CN) exposure from the cyanogenic glucoside linamarin in cassava and the methods used to process this impor tant root crop were studied in Tanzania. An outbreak of acute intoxications in southern Tanzania coincided with a drought in 1988. The affected population attributed intoxications to short-cuts made in the sun-drying of cassava roots. Processing experiments showed that these short-cuts yielded flour with high residual levels of cyanohydrin, a linamarin metabolite that is transformed to CN in the gut. A causal role of CN in the intoxications was supported by hundred-fold higher mean urinary levels of the main metabolite thiocyanate (SCN) in affected (1120 pmol/1) compared to non-aftected (7 pmol/1) population groups. An epidemic of the paralytic disease konzo, that has been attributed to CN exposure from cassava, occurred during a drought in northern Tanzania in 1985. Qualitative and quantitative interviews revealed that the estab lished way of heap-fermenting crushed cassava roots was shortened during the drought due to food shortage and intensive trade. Experiments showed that this chain of events resulted in high levels of cyanohydrin in flour. Low protein intake may have enhanced CN toxicity due to low supply of sulphur for CN to SCN conversion. Studies of 217 women from an iodine deficient area in western Tanzania showed that the total goitre rate of 73 % could be explained by iodine deficien cy as verified by a median urinary iodine of 3.6 pg/dl. Although 98% ate cassava roots daily their mean urinary SCN was only 128 pmol/1. Use of mechanical milling was associated with low SCN, probably because milling ensures complete drying of roots, which removes cyanohydrin. A mean urinary SCN of 36 pmol/1 indicated low CN exposure in 193 schoolchildren studied in Dar es Salaam. They consumed cassava roots without prior processing that effectively removes cyanogens. The low CN exposure can be explained by the use of non-bitter varieties with low linamarin levels and low consumption frequency and that ingested linamarin is partly excreted in the urine without releasing cyanide in the body.
Changes in acidity of plant growth media during heat sterilisation
(Journal of Applied Biosciences, 2008) Msogoya, T. J.; Maerere, A. P.; Nzogela, Y.; Kusolwa, P. M.
Tissue culture media provide ideal conditions for growth of plant cells, but also bacteria and fungi. It is therefore necessary to sterilize media to remove these microbes prior to incubation of explants. Growth media are commonly sterilised by autoclaving at 121°C and pressure of 105 kPa for 15 minutes, or longer for larger volumes (Beyl, 2000). Some components of the growth media such as gibberellins (GA3) and capanthothenate are heat-labile and would become inactive when autoclaved (Nissen & Sutter, 1990). Such heat sensitive components are sterilised by filtering through bacteria-proof membrane (0.22μm pores) and added to the sterilised medium after it has cooled down to at least 60°C. Autoclaving the growth media at 121°C and pressure of 105 kPa for 15 - 20 minutes also breaks down sucrose into D-glucose and Dfructose, resulting in alteration in the osmotic potential of the growth media. Thus, it is important to consider these changes when performing osmotic-sensitive procedures such as protoplast culture. Moreover, the simple sugars resulting from sucrose degradation apparently have inhibitory effects on in vitro regeneration of some plant tissues (Dodds & Roberts, 1990).
Characterisation of botanical starches as potential substitutes of agar in tissue culture media
(Africa Journal of Biotechnology, 2015) Madege, R.; Mneney, E.; Misangu, R.; Maerere, A.
Seven botanical starches; cassava, sweet potato, Irish potato, maize, rice, wheat and sorghum were characterized to determine physicochemical properties influencing gel formation for preparation of tissue culture media. Total starch, protein, fat, amylose content, swelling power and pH were determined using acid hydrolysis, enzymic and spectrophotmetric methods. Each type of starch was tested for ability to support in vitro plant growth and 0.8% agar (w/v) was used as standard. Nodal explants cultures were initiated in Murashige and Skoog medium supplemented with 3% sucrose and 0.5 mg/l benzylaminopurine (BAP). After 21 days, number of leaves and nodes, plant height and fresh weight were determined for each treatment. Significant (0.05) differences were observed between starch types in total starch, protein content and fats. Cassava had the highest starch content (81.5%) and irish potato had the lowest (29.3%). Highest protein content (12%) was observed in maize starch and the lowest (3.4%) in cassava. Fat content was highest (6.2%) in wheat and lowest in cassava (0.2%). Starch extract from rice had the highest amylose content (31.12%) while the cassava starch extracts had the lowest (20.75%). The starch extracted from wheat had the highest swelling power (105.1%) while irish potato starch had the lowest (52.1%). Sorghum starch had the lowest pH of 4.57 while the highest (6.92) was recorded in Irish potato starch. The growth of shoots in vitro on agar gelled media outperformed those of starch gelled media except for the number of leaves per shoot which cassava starch media recorded significantly the highest response (P = 0.05). Of all the starch gelled media, the best growth response was observed with cassava. Good performance was observed in starches with high starch content, low amylose content and high swelling powers.
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.
Characterization of the common bean host and Pseudocercospora griseola, the causative agent of angular leaf spot disease in Tanzania
(African Journal of Plant Science, 2016) Chilagane, Luseko Amos; Msolla, Susan Nchimbi; Kusolwa, Paul Mbogo; Porch, Timothy Gabriel; Diaz, Luz Miryam Serrato; Tryphone, George Muhamba
Angular leafspot (ALS), caused by the fungus, Pseudocercospora griseola, is one of the most important disease of common bean in Tanzania. Breeding for resistance to this disease is complicated by the variable nature of the pathogen. In Tanzania, a thorough analysis of the variability of this pathogen is lacking which limits breeding for durable resistance. This work aimed at characterizing P. griseola in relation to its host in Tanzania. A sample collection of both P. griseola and common bean was conducted in the 2013 and 2014 growing seasons from nine regions. Single spore isolation was performed for P. griseola isolates and DNA was extracted from both P. griseola mycelium and bean leaves from which the pathogen was collected. For characterization of the gene pool origin of the host, Phaseolin DNA marker was evaluated and for the pathogen, the Internal Transcribed Spacer region (ITS) and the Actin gene sequences were evaluated. Phylogenetic analysis showed the presence of 69.7% Andean and 30.3% Mesoamerican strains of P. griseola in Tanzania. The common bean host genotypes showed a similar distribution with 84.2% Andean and 15.8% Mesoamerican. In both cases, Andean strains of the pathogen and Andean bean genotypes outnumbered Mesoamerican. In relation to the common bean genotypes, Andean genotypes were more susceptible to ALS as compared to Mesoamerican genotypes. There were few strains that were of Andean origin but were pathogenic on Mesoamerican common bean genotypes, a group that has previously been termed Afro-Andean. Geographically, most of the regions of Tanzania had only Andean strains except for Kagera where 60% were Mesoamerican strains, and in Arusha and Tanga, where 50 and 33% were Mesoamerican, respectively. Only three regions, Kagera, Mbeya and Rukwa, were found to grow Mesoamerican beans. The findings of this study are important in setting basic objectives for breeding for angular leaf spot disease in Tanzania.
Climate change perceptions by smallholder coffee farmers in the Northern and Southern highlands of Tanzania and bioresearch
(MDPI, 2021) Mbwambo, Suzana G; Mourice, Sixbert K; Tarimo, Akwilin J. P
Smallholder farmers are among the most vulnerable groups to climate change. Efforts to enhance farmers’ adaptation to climate change are hindered by lack of information on how they are experiencing and responding to climate change. Therefore, this paper examines smallholder farmers’ perceptions of climate change, factors influencing their perceptions, and the impacts and adaptation strategies adopted over the past three to four decades. A list of farmers was obtained from the Agricultural Marketing Cooperative Society (AMCOS) and filtered on the basis of age and farming experience. In order to explore factors influencing household perceptions of climate change, a structured questionnaire was administered to the randomly selected household heads. Data on rainfall and temperature were acquired from Lyamungo and Burka Coffee estate (Northern Highlands zone) and Mbimba and Mbinga (Southern Highlands zone) offices of the Tanzania Meteorological Agency (TMA) with the exception of data from Burka Coffee estate, which were acquired from a private operator. Descriptive statistics and logistic regression models were used to analyze the data. Farmers’ perceptions were consistent with meteorological data both pointing to significant decline in rainfall and increase in temperature since 1979. Factors such as level of education, farming experience, and access to climate information influenced farmers’ perception on climate change aspects. Based on these results, it is recommended to enhance timely and accurate weather information delivery along with developing institutions responsible for education and extension services provision. The focus of education or training should be on attenuating the impacts of climate change through relevant adaptation measures in each coffee-growing region.
Climate change; Farm level definition, causes, perceived impacts and coping mechanisms in three farming systems of Tanzania
(2016) Madege, Richard Raphael; Msemwa, John; Lymo, Dominick
Despite the numerous general codes of practices to adapt to climate change, many farming communities are still vulnerable partly due to lack of locally adapted measures. This research was conducted to establish socioeconomic factors influencing vulnerability and adaption to climate change in three farming systems of Tanzania. Participatory techniques were used to investigate how farmers defined climate change, perceived its impacts to agriculture and their coping mechanisms. All had knowledge that climate change is happening but the differed in the way they defined the phenomenon, perceived its impacts and the adaptation strategies they took. More than 80% of the farmers had no correct definition of climate change. 5% to 20% defined climate change in the context of rainfall variability and warming up of the earth. Less than 5% had knowledge that climate change is associated with emission of green house gases, deforestation, environmental degradation, and poor production practices. Positive and negative impacts of climate change were reported in all the farming systems. Between the farming systems, differences in coping mechanisms were noted. Coping strategies and socioeconomic characteristics were correlated. Indigenous coping strategies and the socioeconomic status should be considered when planning for climate sensitive agriculture.
Common weeds found in selected cassava farms in Eastern zone of Tanzania
(Greener Journal of Agricultural Sciences, 2022-04-04) Leonard, Joseph A.; Kudra, Abdul B.; Baijukya, Frederick; Tryphone, George M.
A field study was conducted at Kiimbwanindi village, Mkuranga district and Ilonga village, Kilosa district. Coast and Morogoro regions of Tanzania, respectively to identify the common weeds affecting cassava fields. A total of 24 random 1 m × 1 m quadrat were placed in each cassava field where by all weed species found in each quadrat were identified to a species level. During weed identification, weed density, uniformity and frequency were calculated according to Thomas methodology and used to determine weeds’ relative abundance. Also, a composite soil samples were collected based on random sampling procedure at a depth of 0 to 50 cm from each field before land preparation and analysed in the laboratory in order to determine the amount of nutrient content available in the soil. A total of 22 weeds species belonging to 16 families were identified, whereby out of these 14 were broad leaved weeds, 6 grassy weeds, 1 mushroom and 1 sedged weed belonging to 10 perennial and 12 annual weeds plant. During weed identification, Cyperus rotundus and Echinochloa colona were the most abundantweed species while Dactyloctenium aegyptium, Portulaca oleracea, Agaricus sp and Bidens pilosa were the least occurred weed species. Perennial weeds Cyperus rotundus, Echinochloa colona, Trichodesma zeylanicum, Reissantia sp, Mucuna pruriens and Commelina benghalensis found to be the mostly abundant weed species due to their ability to adapt into various soil types and their ability to reproduce as compared to other weeds. The study recommended that, research toward new or improved weed control measures is needed and also more survey work is needed on a regular basis to identify possible weed population shifts.

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