Articles, Conference and Workshop Papers Collection

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    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.
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    Controlling Tuta absoluta (Meyrick) by Selected Crude Plant Extracts in the Laboratory and in the Screen House
    (David Publishing, 2019) Matendo, Rehema Esther; Nonga, Hezron Emmanuel; George, Bakari; Nabintu Bintu, Ndusha; Mwatawala, Maulid Walad; Maerere, Amon Petro
    Effects of Commiphora swynnertonii, Synadenium glaucescens and Allium sativum extracts on the tomato leaf miner, Tuta absoluta (Meyrick) were evaluated on the adults and in screen house conditions. The adult stage was involved with 30 adults that were reared in an insectarium, the experimental design was a completely randomized design (plant extracts from three plants species  three doses of 2%, 4% and 8%). In the screen house, experimental dispositive was a completely randomized block design (two varieties of tomatoes  three plants extracts). Larval counts were performed after 0, 1, 2, 3 and 7 d of treatment, 40 tomato leaves (10  4 replicates) were randomly taken from each treatment. The mean percentage mortality of adults was recorded daily for 5 d. Results indicated that, each plant extract caused significant mortality to adults of T. absoluta after 5 d in comparison to the control. Leaf dipping against adult of T. absoluta proved to be the most effective for all plant extracts at 30%-100%. Commiphora resulted in the adults’ mortality of 100%. In the screen house Commiphora showed the high reduction of infestation for Tanya and Cal J varieties. Treatment with this plant extract resulted in the highest fruit yield and the lowest yield loss compared to all the plant extracts. C. swynnertonii extract is recommended into integrated pest management strategies for the control of T. absoluta.
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    UAV-based multispectral vegetation indices for assessing the interactive effects of water and nitrogen in irrigated horticultural crops production under tropical sub-humid conditions: A case of African eggplant
    (Elsevier, 2022) Mwinuka, Paul Reuben; Mourice, Sixbert K; Mbungu, Winfred B; Mbilinyi, Boniphace P; Tumbo, Siza D; Schmitter, Petra
    UAV-based multispectral vegetation indices are often used to assess crop performance and water consumptive use. However, their ability to assess the interaction between water, especially deficit irrigation, and nitrogen application rates in irrigated agriculture has been less explored. Understanding the effect of water-nitrogen in teractions on vegetation indices could further support optimal water and N management. Therefore, this study used a split plot design with water being the main factor and N being the sub-factor. African eggplants were drip irrigated at 100% (I100), 80% (I80) or 60% (I60) of the crop water requirements and received 100% (F100), 75% (F75), 50% (F50) or 0% (F0) of the crop N requirements. Results showed that the transformed difference vegetation index (TDVI) was best in distinguishing differences in leaf moisture content (LMC) during the vegetative stage irrespective of the N treatment. The green normalized difference vegetation index (GNDVI) worked well to distinguish leaf N during vegetative and full vegetative stages. However, the detection of the interactive effect of water and N on crop performance required a combination of GNDVI, NDVI and OSAVI across both stages as each of these 3 VI showed an ability to detect some but not all treatments. The fact that a certain amount of irrigation water can optimize the efficiency of N uptake by the plant is an important criterion to consider in developing crop specific VI based decision trees for crop performance assessments and yield prediction.
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    Fungicidal effects of commiphora swynnertonii (burrt.) and synadenium Glaucescens (pax.) against tomato fusarium wilt disease
    (Elservier, 2023) Madege, Richard R; Babu, Saidi; Mabiki, Faith P; Mtui, Hosea; Kudra, Abdul
    Tomato fusarium wilt disease is an important soil-borne disease caused by Fusarium oxysporum f. sp. Lycopersici (FoL) worldwide. The disease causes yield losses of about 90% worldwide. This study aimed to evaluate the extracts of C. swynnertonii (resins) and S. glaucescens (latex, fresh and dry leaves) for their efficacy against FoL. In the laboratory, a 4 × 4 factorial experiment in a Complete Randomized Design (CRD) was carried out to evaluate resins, latex, fresh, and dry leaves each in four concentrations (0.01 g/ml, 0.05 g/ml, 0.1 g/ml and 0.15 g/ml). The negative and positive controls were Sterile Distilled Water (SDW) and a Linkmil 72 WP (Mancozeb 64% + Metalaxyl 8%) respectively. In a screenhouse, resins, latex, and fresh and dry leaves, each at 0.15 g/ml were applied on pre-inoculated tomato plants to manage TFW disease. The experiment was laid out in a Randomized Complete Block Design (RCBD) with four replications. The negative and positive controls were the untreated soil and soil treated with Linkmil 72 WP respectively. The differences between extracts in the in- hibition of radial mycelial growth of the pathogen were highly significant (p = 0.000). The efficacy of the plant extracts against in vitro growth of FoL was significantly dependent on the application dose. The inhibition of mycelial growth caused by latex and dry leaves was higher than that of Linkmil 72 WP (23.58%) and SDW (0%) by 41% and 65% respectively. Findings show that there was a TFW disease reduction of 72.92% 68.75% and 56.25% in plants treated with dry leaves, the latex of S. glaucescens, and resin of C. swynnertonii in that order. Plant extracts had significant effects (p = 0.000) on plant growth. The plants treated with dried leaf powder attained the highest height, the number of branches/plant, leaves/plant, and leaf area of 85.85 cm, 19.25,99.5 and 59.39 respectively. The findings benchmark the fungicidal potential of C. swynnertonii and S. glaucescens.
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    The feasibility of hand-held thermal and UAV-based multispectral imaging for canopy water status assessment and yield prediction of irrigated African eggplant (Solanum aethopicum L)
    (Elsevier, 2021) Mwinuka, Paul Reuben; Mbilinyi, Boniface P; Mbungu, Winfred B; Mourice, Sixbert K; Mahoo, H.F; Schmitter, Petra
    This study was conducted to evaluate the feasibility of a mobile phone-based thermal and UAV-based multi spectral imaging to assess the irrigation performance of African eggplant. The study used a randomized block design (RBD) with sub-plots being irrigated at 100% (I100), 80% (I80) and 60% (I60) of the calculated crop water requirements using drip. The leaf moisture content was monitored at different soil moisture conditions at early, vegetative and full vegetative stages. The results showed that, the crop water stress index (CWSI) derived from the mobile phone-based thermal images is sensitive to leaf moisture content (LMC) in I80 and I60 at all vegetative stages. The UAV-derived Normalized Difference Vegetation Index (NDVI) and Optimized Soil Adjusted Vegetation Index (OSAVI) correlated with LMC at the vegetative and full vegetative stages for all three irrigation treatments. In cases where eggplant is irrigated under normal conditions, the use of NDVI or OSAVI at full vegetative stages will be able to predict eggplant yields. In cases where, eggplant is grown under deficit irri gation, CWSI can be used at vegetative or full vegetative stages next to NDVI or OSAVI depending on available resources.
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    Identification of drought tolerant rice (Oryza Sativa L.) genotypes with Asian and African Backgrounds
    (MDPI, 2023) Ndikuryayo, Cyprien; Ndayiragije, Alexis; Kilasi, Newton Lwiyiso; Kusolwa, Paul
    Drought is among the major abiotic stresses on rice production that can cause yield losses of up to 100% under severe drought conditions. Neither of the rice varieties currently grown in Burundi can withstand very low and irregular precipitation. This study identified genotypes that have putative quantitative trait loci (QTLs) associated with drought tolerance and determined their performance in the field. Two hundred and fifteen genotypes were grown in the field under both drought and irrigated conditions. Genomic deoxyribonucleic acid (DNA) was extracted from rice leaves for further genotypic screening. The results revealed the presence of the QTLs qDTY12.1, qDTY3.1, qDTY2-2_1, and qDTY1.1 in 90%, 85%, 53%, and 22% of the evaluated genotypes, respectively. The results of the phenotypic evaluation showed a significant yield reduction due to drought stress. Yield components and other agronomic traits were also negatively affected by drought. Genotypes having high yield best linear unbiased predictions (BLUPs) with two or more major QTLs for drought tolerance, including IR 108044-B-B-B-3-B-B, IR 92522-45-3-1-4, and BRRI DHAN 55 are of great interest for breeding programs to improve the drought tolerance of lines or varieties with other preferred traits.
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    Optimizing methods for rearing mated queens and establishing new colony of Oecophylla longinoda (Hymenoptera: Formicidae)
    (International Journal of Tropical Insect Science, 2017) Rwegasira, Rozalia G; Mwatawala, Maulid W; Rwegasira, Gration M; Axelsen, Jörgen
    Oecophylla spp. are used as biocontrol agents for many types of insect pests. A large and stable population is essential for effective control of pests. Colonies of Oecophylla spp. can be transplanted from wild habitats into orchards. Transplanted colonies can only survive in the presence of egg laying queens. It is difficult to locate nests with egg laying queens in large colonies that may sometimes contain more than 100 nests. Therefore, the need to explore and develop methods for rearing newly mated queens in nurseries may not be over emphasized, hence the current study. In the first experiment, we tested three rearing methods on queen survival and colony establishment. In the second experiment, we compared feeding techniques of different weaver ants on young colony growth. We observed that queens were best reared under continuous, indirect access to water. The first workers emerged earlier (32 days on average) in indirect and direct continuous access to water methods than on limited access to water (sprinkled) (38 days on average). Moreover, rearing mated queens under continuous indirect access and continuous direct access to water methods saved labour and time, because of limited attendance to the colonies. Availability of water, sugar solution and different sources of protein throughout improved the growth of young colonies. Likewise, the number of workers increased rapidly. Therefore rearing mated queens in nurseries is possible and would minimize hustles in hunting for the colonies and their queens in the wilderness
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    Non true seed production practices and certification requirements: a review
    (International Journal of Innovative Science and Research Technology, 2023) Bahati, Fungameza; Richard, Madege; Nzogela, Yasinta
    An effective seed system for non-true seed crops in developing countries are essential in safeguarding supply of planting material to local farmers. Continuing disregard of the distinct biological characteristics of non true seed crop by regulatory body, limit farmers to access high-quality planting material thus increasing the risk of pest and disease transmission. This paper is designed to presents methodologies used in certification procedures of non-true seed crops and the smart mango grafting practices that implies development of quality and certifiable planting materials. The main contribution of this study is to showcase the smart grafting practices that would help the regulatory bodies in the country to establish and enforce the certification standard of non-true seed crops specifically Mango, to guarantee the availability of quality planting material to farmers as well as making a fully control of non-true seed business just like the true seed crop business is.
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    Prevalence and Management of Phytopathogenic Seed-Borne Fungi of Maize
    (MDPI, 2023) Erasto, Rehema; Kilasi, Newton; Madege, Richard Raphael
    Seed-borne fungi are solemn and deleterious pathogens capable of causing significant losses of quantity and quality losses in maize seeds and seedlings. They infect the crop at all points of the production chain from farms to stores. A yield loss of up to 50% can be encountered. Currently, chemical control of the disease is being implemented, though it is accompanied by several negative effects. This study aimed at identifying seed-borne fungi of maize and effective management options. A deep-freezing blotter method and morphological identification of the fungal species were implemented. The seed-borne fungi detected were Fusarium verticillioides, Aspergillus flavus, Aspergillus niger, Penicillium spp., Rhizopus spp., and Curvularia spp. However, in farmer-saved seeds, fungal incidences were significantly higher (p < 0.01) than in certified seeds. To identify more effective management options, the efficacy of water and ethanol-extracted bio-fungicides from three plant species, namely, neem (Azadirachta indica), ginger (Zingiber officinale), and coffee (Coffea arabica) were evaluated. From in vitro assays, ethanol-extracted bio-fungicides have a 100% inhibitory effect on fungal growth, whilst the inhibitory effects of water-extracted bio-fungicides are 55.88% (Azadirachta indica) and 46.31% (Zingiber officinale), followed by 5.15% (Coffea arabica). For the case of an in vivo assay, maize seeds treated with water-extracted bio-fungicides have higher seed germination and seedling vigor percentages. For germination, seeds treated with water-extracted bio-fungicides have higher percentages (neem and ginger (90%) followed by coffee (72.5%)) than ethanol-extracted bio-fungicides (neem (0%), ginger (2.5%), and coffee (0%)). A similar observation is made for seedling weight. Therefore, the tested water-extracted bio-fungicides can be used in treating seeds before sowing them. Further studies on effective methods of extracting bioactive compounds, and improving their shelf life, are recommended.
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    Long-term spatial-temporal trends and variability of rainfall over Eastern and Southern Africa
    (Springer, 2019) Muthoni, Francis Kamau; Odongo, Vincent Omondi; Ochieng, Justus; Mugalavai, Edward M; Mourice, Sixbert Kajumula; Hoesche-Zeledon, Irmgard; Mwila, Mulundu; Bekunda, Mateete
    This study investigates the spatial-temporal trends and variability of rainfall within East and South Africa (ESA) region. The newly available Climate Hazards group Infrared Precipitation with Stations (CHIRPS-v2) gridded data spanning 37 years (1981 to 2017) was validated against gauge observations (N = 4243) and utilised to map zones experiencing significant monotonic rainfall trends. Standardised annual rainfall anomalies revealed the spatial-temporal distribution of below and above normal rains that are associated with droughts and floods respectively. Results showed that CHIRPS-v2 data had a satisfactory skill to estimate monthly rainfall with Kling-Gupta efficiency (KGE = 0.68 and a high temporal agreement (r = 0.73) while also preserving total amount (β = 0.99) and variability (γ = 0.8). Two contiguous zones with significant increase in annual rainfall (3–15 mm year−1 ) occurred in Southwest Zambia and in Northern Lake Victoria Basin between Kenya and Uganda. The most significant decrease in annual rainfall (− 20 mm year−1 ) was recorded at Mount Kilimanjaro in Tanzania. Other significant decreases in annual rainfall ranging between − 4 and − 10 mm year−1 were observed in Southwest Tanzania, Central-South Kenya, Central Uganda and Western Rwanda. CHIRPS-v2 rainfall product provides reliable high spatial resolution information on amount of rainfall that can complement sparse rain gauge network in rain-fed agricultural systems in ESA region. The observed spatial-temporal trends and variability in rainfall are important basis for guiding targeting of appropriate adaptive measures across multiple sectors.
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    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.
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    A review of selected preharvest management options of aspergillus flavus and aflatoxin contamination of maize in Tanzania
    (International Journal of Agriculture, Environment and Bioresearch, 2022) Tito, Goodluck P; Mugula, Jovin K; Madege, Richard Raphael
    Maize (Zea mays L.) is a staple food in Tanzania, but it is often susceptible to aflatoxin contamination caused by the Aspergillus flavus fungi. Aflatoxin contamination in crops is influenced by insufficient knowledge of pre-harvest management practices. Due to the toxic nature of aflatoxins, their proportions and concentrations in various food ingredients are subject to strict regulations in developed countries. The contamination resulting from aflatoxins remains one of the critical mycotoxin challenges in Tanzania because it affects food safety, security, trade, and human health. Either, an integrated combination of intervention measures such as biocontrol is the perfect strategy for sustainable reduction of A. flavus and aflatoxin production in maize. This paper explores several agricultural approaches that potentially reduce aflatoxins production in maize. Selected bio-controls such as Trichoderma spp and Atoxigenic A.flavus are among these strategies. The anticipation of this appraisal is to stimulate improvement of the existing aflatoxin management methods and inventions to exploit their effectiveness in managing toxigenic A.flavus and Aflatoxin production at harvest.
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    Effects of antifungal plant extracts on improving maize seedling emergence and plant growth
    (International Seed Testing Association, 2022) Erasto, Rehema; Madege, Richard Raphael; Kilasi, Newton
    Maize seeds are usually contaminated with seed-borne fungi which cause seed deterioration and seedling death. Seed treatment using chemical fungicides is a common practice, although fungicides can reduce seed longevity and lead to residues, resistance, and environmental pollution. This study was conducted to determine the effects of plant extracts (PEs; Azadirachta indica, Coffea Arabica, and Zingiber officinale) on seedling emergence and seedling vigour of certified (CS) and farmer-saved (FSS) seeds of maize. Seeds treated with water-extracted PEs had significantly higher seedling emergence with 85.8% and 61.7% for FSS and CS, respectively, while ethanol-extracted PEs had 6.7% and 7.5% seedling emergence for FSS and CS, respectively. The minimum mean number of days to the first emergence was less for seeds treated with water-extracted PEs (3.0 and 3.3 for FSS and CS, respectively) than those treated with ethanol-extracted PEs (6.3 and 7.0 for FSS and CS, respectively). According to this study, water-extracted PEs are potential candidates in seed treatment, because they have fewer adverse effects on seedling emergence and vigour. Although other studies mention PEs extracted using organic solvents to be the best, the study’s recommendation is to ensure that organic solvents are completely removed from PE solutions before using them.
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    Optimizing water and nitrogen application for neglected horticultural species in tropical sub-humid climate areas: a case of African eggplant (Solanum aethiopicum L.)
    (Elsevier, 2021) Mwinuka, Paul Reuben; Mbilinyi, Boniface P; Mbungu, Winfred B; Mourice, Sixbert K; Mahoo, Henry F; Schmitter, Petra
    African eggplant, a traditional and important nutrient-dense crop to Tanzania’s nutrition and food security. However, yields remain low as a result of sub-optimal irrigation and fertilizer practices. To reduce the yield gap, a randomized split-plot design set up with irrigation as a main and nitrogen (N) treatments as a sub-factor. The irrigation regimes were 100 % (I100), 80 % (I80) and 60 % (I60) of crop water requirements whilst nitrogen levels were 250 kg N/ha (F100), 187 kg N/ha (F75), 125 kg N/ha (F50) and 0 kgN/ha (F0). The study evaluated the effect of irrigation water and N on crop growth variables and yield, fruit quality, WUE and NUE. The study showed the importance of combining different irrigation performance indicators which responds to different levels of water and nitrogen to evaluate and assess suitable irrigation and fertilizer strategies for African eggplant. The crop growth variables (plant height and LAI) had a good correlation with fruit yield (R2 = 0.6 and 0.8). The fruit quality was best performed by 100 % water in combination with 75 % N treatment. The best WUE and NUE was attained at 80 % and 100 % levels of water in combination with 75 % N. However, minimizing trade-offs between the various indicators, the optimal application for African eggplant would likely be around 80 % of the total irrigation requirement and 75 % of the N requirement in sandy clay loam soils under tropical sub humid conditions.
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    The use of light to enhance weaver ant oecophylla longinoda latreille (Hymenoptera: Formicidae) queen catches
    (Sociobiology, 2017) Nene, W; Offenberg, J; Rwegasira, GM; Mwatawala, M
    Production of live weaver ant (Oecophylla longinoda and O. smaragdina) colonies is being developed as the ants provide several ecosystem services in agriculture and as they are used in education and research laboratories. Founding queens needed for colony production can be caught in artificial nests made of live leaves that are curled on trees. In this study we investigated if the catch rate of O. longinoda queens in artificial nests could be improved by attracting queens to trees with a light source (electric torches). We compared catch rates of 50 artificial nests on each of eight citrus trees, four of them with light and four without light. During two mating seasons covering 9 mating flights we caught a total of 178 queens. However, 3.8 times more queens were caught in the trees with light compared to trees without light. We conclude that queen catches can be highly improved by combining artificial nests with an attracting light source.
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    Description of new ceratitis species (Diptera: Tephritidae) from Africa, or how morphological and DNA data are complementary in discovering unknown species and matching sexes
    (European Journal of Taxonomy, 2016) De Meyer, Marc; Mwatawala, Maulid; Copeland, Robert S; Virgilio, Massimiliano
    This paper describes five new Ceratitis species from the eastern and southern parts of the Afrotropical Region: C. (Pterandrus) quilicii De Meyer, Mwatawala & Virgilio sp. nov.; C.(Ceratalaspis) pallidula De Meyer, Mwatawala & Virgilio sp. nov.; C. (Ceratalaspis) taitaensis De Meyer & Copeland sp. nov.; C. (Ceratalaspis) sawahilensis De Meyer & Virgilio sp. nov.; and C. (Ceratalaspis) flavipennata De Meyer & Virgilio sp. nov. Their relationships with closely allied species within their respective subgenera are discussed where appropriate, and diagnostic characters are given. DNA barcodes are provided for all new species. In addition, the hitherto unknown male of C. (Pardalaspis) serrata De Meyer, 1996 is described, based on material collected in the Democratic Republic of Congo. Recognition of these new species and sexes is the result of an integrative approach using morphological characters and DNA data
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    Effect of Watering Regimes on Yield and Agronomic Traits of Exotic Groundnut Genotypes in Tanzania
    (Journal of Advances in Biology & Biotechnology, 2019) Philipo, Mashamba; Nchimbi-Msolla, Susan
    Groundnut (Arachis hypogaea L.) production in rain fed regions of Africa is mostly affected by intermittent drought of different duration and intensity. Improvement of groundnuts for drought tolerance could increase production in drought prone areas. Therefore, this study aimed at (i) determining the effect of Watering regimes on yield and agronomic traits of exotic Groundnut genotypes and (ii) identifying drought tolerant genotypes as source material for breeding and drought tolerant varieties. Thirty groundnut genotypes were evaluated for drought tolerance under well watered and water stress conditions in the screen house at Sokoine University of Agriculture (SUA), Tanzania. A split plot design with four replications was used whereby the watering regimes were the main plots with varieties planted as subplots Data were recorded on plant height, number of pod/plant and pod yield/plant. Results showed that drought significantly reduced pod yield, number of pods/plant and plant height. Eleven genotypes namely; ICG 2106, ICR 48, ICGS 44, ICG 3053, ICG 11088, ICGV-SM 87003, ICG 12235, ICG 13723, ICGV 02271, ICGV 97182 and ICGV 91114 gave better pod yield and number of pods/plants in water stress conditions and are recommended for use in breeding program as drought tolerant varieties and sources for breeding materials.
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    The role of genotype and production environment in determining the cooking time of dry beans (Phaseolus vulgaris L.)
    (Wiley Periodicals, Inc., 2019) Cichy, Karen A; Wiesinger, Jason A; Berry, Matthew; Nchimbi‐Msolla, Susan; Fourie, Deidre; Porch, Timothy G; Ambechew, Daniel; Miklas, Phillip N
    Dry bean (Phaseolus vulgaris L.) is a nutrient‐dense food rich in proteins and minerals. Although a dietary staple in numerous regions, including Eastern and Southern Africa, greater utilization is limited by its long cooking time as compared with other staple foods. A fivefold genetic variability for cooking time has been identified for P. vulgaris, and to effectively incorporate the cooking time trait into bean breeding programs, knowledge of how genotypes behave across diverse environments is essential. Fourteen bean genotypes selected from market classes important to global consumers (yellow, cranberry, light red kidney, red mottled, and brown) were grown in 10 to 15 environments (combinations of locations, years, and treatments), and their cooking times were measured when either presoaked or unsoaked prior to boiling. The 15 environments included locations in North America, the Caribbean, and East ern and Southern Africa that are used extensively for dry bean breeding. The cooking times of the 14 presoaked dry bean genotypes ranged from 16 to 156 min, with a mean of 86 min across the 15 production environments. The cooking times of the 14 dry bean genotypes left unsoaked ranged from 77 to 381 min, with a mean cooking time of 113 min. The heritability of the presoaked cooking time was very high (98%) and moderately high for the unsoaked cooking time (~60%). The genotypic cooking time patterns were sta ble across environments. There was a positive correlation between the presoaked and unsoaked cooking times (r = .64, p < 0.0001), and two of the fastest cooking genotypes when presoaked were also the fastest cooking geno types when unsoaked (G1, Cebo, yellow bean; and G4, G23086, cranberry bean). Given the sufficient genetic diversity found, limited crossover Geno type × Environment interactions, and high heritability for cooking time, it is feasible to develop fast cooking dry bean varieties without the need for exten sive testing across environments.
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    Prediction of cooking time for soaked and unsoaked dry beans (Phaseolus vulgaris L.) using hyperspectral imaging technology
    (The Plant Phenome Journal, 2018-11-25) Mendoza, Fernando A; Wiesinger, Jason A; Lu, Renfu; Nchimbi-Msolla, Susan; Miklas, Phillip N; Kelly, James D; Cichy, Karen A
    The cooking time of dry bean varies widely by genotype and is also influenced by the growing environment, storage conditions, and cooking method. Thus high-throughput phenotyping methods to assess cooking time would be useful to breeders interested in developing cultivars with a desired cooking time. The objective of this study was to evaluate the performance of hyperspectral imaging technology for predicting dry bean cooking time. Fourteen dry bean genotypes with a wide range of cooking times were grown in five environments over 2 yr. Hyperspectral images were taken from whole dry seeds, and partial least squares regression models based on the extracted hyperspectral image features were developed to predict water uptake and cooking time of soaked and unsoaked beans. Relatively good predictions of water uptake were obtained, as mea-sured by the correlation coefficient for prediction (Rpred = 0.789) and standard error of prediction (SEP = 4.4%). Good predictions of cooking time for soaked beans (ranging between 19.9–95.5 min) were achieved giving Rpred = 0.886 and SEP = 7.9 min. The pre-diction models for the cooking time of unsoaked beans (ranging between 80–147 min) were less robust and accurate (Rpred = 0.708, SEP = 10.6 min). This study demonstrated that hyperspectral imaging technology has potential for providing a nondestructive, simple, fast, and economical means for estimating the water uptake and cooking time of dry bean. Moreover, a totally independent set of 110 similar dry bean samples confirmed the suitability of the technique for predicting cooking time of soaked beans after updat-ing the partial least squares model with 20 of the new samples, giving Rpred = 0.872 and SEP = 3.7 min. However, due to the genotypic and phenotypic variability of water absorption and cooking time in dry bean, periodical updates of these prediction models with more samples and new bean accessions, as well as testing other multivariate predic-tion methods, are needed for further improving model robustness and generalization.
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    Inheritance of angular leaf spot [Phaeoisariopsis griseola (Sacc.) Ferr] resistance in common bean (Phaseolus vulgaris L.) population developed from Kablanketi x Mexico 54
    (David Publishing, 2012-07-20) Nchimbi-Msolla, Susan; Tryphone, George Muhamba; Chilagane, Luseko Amos; Kusolwa, Paul Mbogo
    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.