Faculty of Agricultural Sciences
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- ItemCompatibility barriers affecting crossability between Solanum aethiopicum and its relatives(Scientific Journals (Nature), 2022) Namutosi, Winnie; Bulyaba, Rosemary; Nakanwangi, Mildred Julian; Buteme, Ruth; Sseremba, Godfrey; Kizito, Elizabeth BalyejusaReproductive barriers are single most important impediment in conventional breeding of Solanum aethiopicum (Shum and Gilo) and its relatives. This study investigated compatibility barriers between S. aethiopicum and its relatives. A randomized complete block design and a full diallel mating method were used to evaluate floral phenology and compatibility of six genotypes at different floral stages. Parameters assessed include; anthesis, anther dehiscence, stigma receptivity, among others. Results showed that most flowers in anthesis per genotype were counted at 8:00am. Overall mean number of open flowers differed significantly (P<0.001) and was highest for N11(n=13) and least for E12(n=3). Anther dehiscence varied significantly (P<.001) among floral stages. However, there was no difference among genotypes. All genotypes showed high pollen viability (> 80%) although they differed significantly (P<0.01). Stigma receptivity averaged highest (3.31) for N11 and least (2.31) for In1. All genotypes exhibited self-compatibility; N11 averaged highest for fruit set (67.93%), seed per fruit (82) and F1 germination (79%). Crosses revealed moderate compatibility (50%); highest fruit were in N4xN11 (71.97%), seed N11xA1 (56) and F1 germination inN11x N4 (76.3%) respectively. In the crosses where In1 was a female parent 80% incompatibility was observed at fruit set whereas73% of crosses where E12 was a female parent set fruits without seed. Female functioning may be a major factor in observed incompatibility between S. aethiopicum and its relatives. To harness the potential of S. aethiopicum relatives, N11 and N4 can be advanced as female parents in wide hybridizations.
- ItemFarmers’ selection cues in cowpea for vegetable use in eastern Uganda(African journal of food, agriculture, nutrition and development, 2022) Kizito, Elizabeth B; Kyebalyenda, T; Nakanwagi, MJ; Sseremba, G; Buteme, R; Kabod, PN1; Odeke; Amayo, R; Runyararo, JR; Egeru, A; Falk, TA participatory cowpea varietal selection was carried out in Eastern Uganda in the Kumi district among farmers (n=30) in the sub-Counties of Ongino, Kumi and Kanyum. An arange of opinions were collected to identify farmers’ selection criteria based on different sensory attributes and their most preferred genotypes for vegetable use. A Apreference analysis was carried out to obtain quantitative preference scores of each plot. This was followed by organoleptic tests which included attributes like taste, aroma and texture of the genotypes at the vegetative and immature R4 stages. Focus group discussions (FGDs) were also held to find a consensus of the independent evaluations made by individual farmers. Data for sixteen (16) cowpea genotypes were collected at the different above-mentioned stages. Quantitative data were analyzed based on farmers’ scores made on the different evaluated attributes and ANOVA was used to provide mean differences between location, gender and genotype at a significant level of 5%. The preference score for each of the varieties tested was determined and presented. Data from FGDs were grouped, similarities and differences were later determined depending on their level of importance to the farmers. Significant differences (p<0.05) in farmer choices were observed for leaf taste, immature pod aroma, taste and texture; mature pod aroma, taste between farmer groups, age genotype and gender. Irrespective of age, gender, farmer group and genotype, farmers seemed to give more importance to the smooth texture, little hard leaves when chewing, sweet taste with a mild aroma (leaves) and a moderate aroma (pods). Majority (9%) of the farmers preferred Ebelat (landrace) at V4 stage; this was followed by Danila (8.7%). On the other hand, UCUCOW1 (13% at immature and 10.2% at mature cooked R4 stage) followed by Ebelat (9% and 9.8% for immature and mature R4 stage, respectively) were preferred by the majority of the farmers. In terms of sensory attributes, farmers preferred genotypes with a sweet taste, moderate aroma and tender texture. The information is a baseline for understanding key farmer selection criteria in the utilization of cowpea as a vegetable which can be used in generating a demand-led variety design for the crop.
- ItemQuantitative and mechanistic analysis of impact of novel cassava-assisted improved processing on fluid transport phenomenon in humidity-temperature-stressed bio-derived films(European Polymer Journal, 2016) Tumwesigye, Kashub Steven; Oliveira, J.C.; Sousa-Gallagher, Maria JoseBio-derived films’ realistic performance integrity is ascertained by their resilience in highly stressful storage conditions, a function of its ability to respond timely and manages fluid barrier appropriately. Bio-derived films’ moisture and temperature sensitivity often posed mass transport challenges, thus decreasing their lifespan. Quantifying bio-derived film mass transport behaviour has been limited to mass transfer representations, which can be imperfect to understand fully mass transport phenomenon. This study reported quantitative and mechanistic analysis of fluid-phase mass transport phenomenon in Simultaneous Release Recovery Cyanogenesis-produced intact bitter cassava (IBC) bio-derived films under stressful conditions. Films were tested for solvent solubility, swelling ratio, sorption and permeability to water vapour and oxygen at 10-40°C and 10-95% RH. Film’s structural alterations were characterised by their thermal and chemical properties. Modified-BET, Peleg, Oswin models best described sorption data. Temperature-dependence of film water vapour permeability was simulated best by Arrhenius model, while oxygen permeability was influenced highly by crystallinity and RH. Non-organic and organic film-solvent diffusion followed case II and Fickian diffusional patterns respectively. Solvents induced structural changes in IBC films with concentration-dependent diffusion. Cassava bio-derived films’ integrity will depend on the host environment, thus maximum care should be ensured to minimise environment impact during applications. Nonetheless, IBC films hold potential as biomaterials for broad range product use.
- ItemNovel Intact Bitter Cassava: Sustainable Development and Desirability Optimisation of Packaging Films(Food Bioprocess Technol Journal, 2016) Tumwesigye, Kashub Steven; Oliveira, J.C.; Sousa-Gallagher, Maria Jose; Montañez, J. C.Novel biomaterials and optimal processing conditions are fundamental in low-cost packaging material production. Recently, a novel biobased intact bitter cassava derivative was developed using an intrinsic, high-throughput downstream processing methodology (simultaneous release recovery cyanogenesis). Processing of intact bitter cassava can minimise waste and produce low-cost added value biopolymer packaging films. The objective of this study was to (i) develop and characterise intact bitter cassava biobased films and (ii) determine the optimal processing conditions, which define the most desirable film properties. Films were developed following a Box-Behnken design considering cassava (2, 3, 4 % w/v), glycerol (20, 30, 40 % w/w) and drying temperature (30, 40, 50 °C) and optimized using multi-response desirability. Processing conditions produced films with highly significant (p < 0.05) differences. Developed models predicted impact of processing conditions on film properties. Desirable film properties for food packaging were produced using the optimised processing conditions, 2 % w/v cassava, 40.0%w/w glycerol and 50 °C drying temperature. These processing conditions produced films with 0.3 %; transparency, 3.4 %; solubility, 21.8 %; water-vapour-permeability, 4.2 gmm/m2/day/kPa; glass transition, 56 °C; melting temperature, 212.6 °C; tensile strength, 16.3 MPa; elongation, 133.3 %; elastic modulus, 5.1MPa and puncture resistance, 57.9 J, which are adequate for packaging applications. Therefore, intact bitter cassava is a viable material to produce packaging films that can be tailored for specific sustainable, low-cost applications.
- ItemNew sustainable approach to reduce cassava borne environmental waste and develop biodegradable materials for food packaging applications(Food Packaging and Shelf Life Journal, 2016) Tumwesigye, Kashub Steven; Oliveira, J.C.; Sousa-Gallagher, Maria JoseTransforming waste cassava into a sustainable resource requires a new approach and redesign of the current processing methodologies. Bitter cassava cultivars have been employed mainly as an emergency famine food, but could also be used as a value-added material for packaging. Processing of intact bitter cassava can minimize waste, and produce low-cost added value biopolymer packaging films for targeted applications. This study developed an improved simultaneous release, recovery and cyanogenesis (SRRC) downstream processing methodology for sustainable reduction of waste and development of film packaging material using intact bitter cassava. SRRC approach produced peeled (BP) and intact (BI) bitter cassava biopolymer derivatives. BI showed significantly higher yields ensuring 16% waste decrease with no environmental impact caused by discard residues. SRRC was very effective in reducing the total cyanogen content to within Codex minimum safety limits, demonstrating that the peeling of bitter cassava process can be avoided. Transparent films were produced using the casting method from both BP and BI derivatives. BI films were more transparent and homogeneous, less soluble, less permeable to moisture, less hydrophilic, more permeable to oxygen and carbon-dioxide, sealable, lower cost, than the BP. Hence, intact bitter cassava and SRRC can be used as sustainable, safe, integrative process solution for high value-added product (e.g., packaging film) production from low-cost biobased materials.