Browsing by Author "Masanza, Michael"

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    Accuracy of using leaf blade length and leaf blade width measurements to calculate the leaf area of Solanum aethiopicum Shum group
    (Heliyon, 2018) Nakanwagi, Mildred Julian; Sseremba, Godfrey; Nahamya, Pamela Kabod; Masanza, Michael; Balyejusa Kizito, Elizabeth
    Leaf area is an important parameter when determining growth response under normal as well as stressed environments. No attempt had been made to come up with an affordable but accurate alternative of measuring leaf size in research neglected leafy vegetable crops. Other techniques such as use of leaf area meters are either destructive, expensive or both. A study was conducted to determine leaf area in like-shaped leaves of research neglected crop plants, taking case of S. aethiopicum Shum group (SAS) germplasm. Data was collected on 552 individual plants (including pure lines and hybrids) at eight weeks after planting where a third fully open leaf from top of each plant was considered. Leaf blade length (LBL) and leaf blade width (LBW) were linearly measured while leaf area (LA) was measured using a leaf area meter. This was followed by correlation and regression analysis of LA with LBL, LBW, and LBL þ LBW. Correlation coefficients at p < 0.001 ranged between 0.84 and 0.92, 0.79 and 0.88, 0.86 and 0.95 for total germplasm, pure lines and hybrids, respectively. The coefficient of determination (R2) ranged between 0.72 and 0.92. The best prediction for LA was obtained with hybrid plants (LA ¼ -165.82 þ 5.38LBL þ 16.17LBW) at R2 of 92%. The implication is that we can accurately and affordably predict LA from duo measurements of LBL and LBW in SAS as well as in other crops having similar leaf shapes.
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    Effect of Different Rates of Poultry Manure and Bio-Slurry on the Yield of Solanum aethiopicum Shum
    (Journal of Agricultural Science, 2018) Nanyanzi, Mary; Balyejusa Kizito, Elizabeth; Masanza, Michael; Sseruwu, Godfrey; Makoma Tenywa, Moses
    Poor soil fertility remains the major cause of low crop productivity on smallholder farms that are engaging in vegetable production in sub-Saharan Africa. Appropriate soil fertility regimes are therefore critical for improving crop productivity. Its yield has remained low mainly due to poor soil fertility. A field experiment in two different seasons was planted in a Completely Randomized Block Design using Solanum aethiopicum Shum (Nakati). The treatments were 3 sole fertilizer options applied at the following rates: poultry manure and bio-slurry manure at 5, 10, 15, 20, 25 and 30 t ha-1, NPK (25:5:5) at the recommend application rate for tomato which is a sister crop and a control without any fertilizer. Crop budgets were used to determine the economic optimum rates of both sole applications of manure and combinations of manure with NPK. The sole applications and showed significantly (p ≤ 0.05) increased the yield of S. aethiopicum compared with the control. The established biological optimum rates were at 24.19 t ha-1 and 21.51 t ha-1 for poultry manure and bio-slurry respectively. Using the crop budgets it was concluded that the established economic optimum rates were 20 t ha-1 and 10 t ha-1 for sole poultry manure and bio-slurry respectively. Recommendations for use of sole poultry manure and bioslurry at the rate of 20 t ha-1 and 10 t ha-1 respectively were made.
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    Identification of growth stage specific watering thresholds for drought screening in Solanum aethiopicum Shum
    (Scientific Reports, 2020) Nakanwagi, Mildred Julian; Sseremba, Godfrey; Kabod, Nahamya Pamela; Masanza, Michael; Balyejusa Kizito, Elizabeth
    Effective phenotyping for drought resistance is a pre-requisite for identification of modest crop varieties for farmers. For neglected and underutilized crops such as Solanum aethiopicum Shum group, no drought screening protocol based on rigorous iterations has been documented. A split-plot nested treatment structure was arranged in an experiment to identify growth stage-specific watering thresholds for this crop. Three plant growth stages (main plot; seedling, vegetative and flowering), watering regime at plant growth stage (2 regimes; well-watered and drought stressed) and day since last watering at plant growth stage were evaluated for soil moisture content (SMC), leaf wilting score (LWS), number of green leaves per plant (LPP) and leaf blade width (LBW). Highly significant differences (p < 0.001) were found at the different plant growth stages, watering regime (WR) within plant growth stage, and day within WR and plant growth stage. Under drought stress treatment, SMC declined exponentially at each stage. The earliest leaf wilting, reduction in LPP and LBW were generally observed at flowering followed by vegetative and slowest at the seedling stage. For future effective drought phenotyping studies in S. aethiopicum Shum and related crops, we recommend setting minimum drought stress treatments below 18% SMC at which the LWS is ≥2 at the vegetative.
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    Performance of Solanum aethiopicum Shum group accessions under repetitive drought stress
    (Journal of Plant Breeding and Crop Science, 2017) Nakanwagi, Mildred Julian; Sseremba, Godfrey; Masanza, Michael; Balyejusa Kizito, Elizabeth
    Drought is a serious climatic hazard to crop production, more especially when it occurs repeatedly. This created a need to identify repetitive drought tolerant varieties that recover following exposure to drought. Twenty accessions of Solanum aethiopicum Shum group were evaluated for their response to repeated drought exposure in a screen house at Uganda Christian University stressed and well-watered conditions in a split-plot arrangement. Data was collected on growth and yield parameters namely leaf area, plant canopy width, plant height, plant branching, fresh leaf weight, fresh shoot biomass, and harvest index. Exposure of plants to repetitive drought stress led to significant decrease in all evaluated growth parameters at p<0.001 except for plant branching. Similarly, yield parameters exhibited a highly significant difference among accessions and between water levels at p<0.001. Principal component analysis of growth rate traits showed that leaf area contributed to the highest variation for recovery from repetitive drought stress among accessions. The accessions that recovered best from drought stress include SAS108/2015, SAS163/P/2015, SAS183/G/2015, and SAS168/G/2015. For yield parameters, the accessions SAS137/2015, SAS148/2015, SAS108/P/2015, and SAS160/2015 had the highest dry shoot biomass. These findings indicate prospect for improvement of tolerance to repetitive drought stress in S. aethiopicum Shum group.
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    Stability of Solanum aethiopicum Shum accessions under varied water deficit stress levels and identification of pertinent breeding traits for resistance to water shortage
    (Euphytica, 2018) Sseremba, Godfrey; Tongoona, Pangirayi; Yaw Eleblu, John Savior; Danquah, Eric Yirenkyi; Kaweesi, Tadeo; Baguma, Yona; Masanza, Michael; Balyejusa Kizito, Elizabeth
    Drought is a major constraint to productivity of Solanum aethiopicum ‘Shum’ group due to loss in market and nutrient value of stressed plants. This study evaluated S. aethiopicum Shum group accessions to identify genotypes (G) that excel across moisture deficit stress levels (WLs). A split-plot arrangement composed of four WLs and twenty accessions of S. aethiopicum as main plot and subplot factors, respectively, was implemented in a screenhouse, and repeated for two experiments. In each experiment, there was a highly significant effect of at least two WLs on mean performance among at least two accessions for most of the traits at p\0.05. Further, very highly significant WL 9 G interactions were obtained for leaf relative water content (LRWC), leaves per plant (LPP) and plant height (PH), and nonsignificant for leaf blade length and leaf blade width. The order of priority as breeding traits for stability superiority across WLs was suggested as LRWC[PH[LPP. Consequently, based on LRWC, the most superiorly stable accessions were identified as accession 160 followed by accessions 145, 137, 108P and 184G while the least stable ones were identified as accessions 163G, 141, 163 and 108. The broad sense heritability (H2) for each of the three recommended traits for drought resistance breeding was above 0.9 thus supportive for a good response to selection. Drought stress negatively affected the performance of S. aethiopicum Shum group but the exhibited variation allowed for selection of superiorly stable genotypes.
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    Stalk-eyed fly, Diopsis sp. population dynamics under varying temperature and Relative Humidity in rice ecosystems
    (2018) Kayongo, Charles; Mbogga, Michael S.; Goncalves de Abreu, Aluana; Masika, Fred; Masanza, Michael; Freitas Barrigossi, Jose Alexandre; Kizito, Elizabeth B.
    Although the stalk-eyed fly (Diopsis sp.) has been observed in Ugandan rice fields, there is limited information on the fly’s population and its potential threat to rice production. This study assessed the stalk-eyed fly (Diopsis longicornis and Diopsis apicalis) population dynamics under varying temperature and relative humidity in rice ecosystems of Uganda. It was conducted in purposively selected small scale rice farming sub-counties in low land rain fed and irrigated rice agro-ecologies (Lake Victoria Crescent, Kasese transition zone and Northern moist farmlands). Diopsis sp. populations were monitored by sampling rice fields every 40 days for a period of 17 months. Weather parameters including air temperature and humidity were recorded by use of data loggers throughout the study period. R-statistical tool and MS Excel were used to assess the population dynamics and interactions of the diopsids. D. longicornis fly was dominantly abundant in rice fields of Lake Victoria Crescent and Northern Moist zones while D. apicalis was dominant in Kasese transition zone. There was significant mean count variations per survey for both species in all the agro-ecological zones with P-values of 0.000958 (D. longicornis) and 1.12e-12 (D. apicalis) in Lake Victoria crescent, 0.000473 (D. apicalis) and 0.0173 (D. longicornis) in Northern moist farmlands, 0.0188 (D. apicalis) and 0.0353 (D. longicornis) in Kasese transition zone. Temperature and relative humidity had a direct effect on the population of both species in Northern moist zone and only on D. apicalis in Kasese transition zone. The optimum/favorable temperatures for abundance were between 27oC and 29oC. Interpretation of the results? Integrated pest management strategies and introduction of improved Diopsis pest resistant rice varieties are some of the recommendations for managing the stalk-eyed fly populations in these rice ecosystems.