Browsing by Author "Derera, John"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    A Comparative Analysis of Conventional and Marker-Assisted Selection Methods in Breeding Maize Streak Virus Resistance in Maize
    (Crop Science, 2009) Abalo, Grace; Tongoona, Pangirayi; Derera, John; Edema, Richard
    Reliable information regarding comparative advantage of marker-assisted selection (MAS) over conventional selection (CS) in breeding for maize streak virus (MSV) resistance in maize (Zea mays L.) is scarcely available. A comparative study was, therefore, conducted to determine the effi ciency of both methods in breeding for MSV resistance in Uganda. Backcross and selfed-progenies were derived from inbred lines CML202 (resistant), CML321, and CML384 (susceptible) using MAS and CS. The experimental lines and their testcross progenies were evaluated for MSV resistance and yield across three locations. Although both breeding approaches were effective in generating MSV-resistant lines, disease incidence was higher in populations under CS (79%) than MAS (62%). A similar trend was observed for area under disease progress curve. However, an equal number of lines generated by MAS and CS displayed high yield potential and MVS resistance in testcrosses. Because all required DNA analysis was performed in an existing laboratory and on a well-characterized quantitative trait locus, costs of capital, equipment maintenance, and marker development were excluded in costing the MAS procedure. Considering total running costs, MAS was cheaper than CS by 26%, which was realized by using fewer plants. Therefore, when laboratory facilities are already established MAS would be recommended in breeding for MSV resistance.
  • Thumbnail Image
    Item
    Grain Yield and Heterosis of Maize Hybrids under Nematode Infested and Nematicide Treated Conditions
    (Journal of nematology, 2011) Kagoda, Frank; Derera, John; Tongoona, Pangirayi; Coyne, Daniel L.; Talwana, Herbert L.
    Plant-parasitic nematodes are present on maize but resistant genotypes have not been identified in Uganda. This study was aimed at determining the level of nematode resistance among F1 hybrids, and to estimate grain yield, heterosis and yield losses associated with maize hybrids under nematode infestation. The 30 F1 hybrids and two local checks were evaluated in a split plot design with nematode treatment (nematode infested versus nematicide treated) as the whole plot factor, and the hybrids as subplot factors arranged in an 8 x 4 alpha-lattice design. The experiment was conducted simultaneously at three sites. The hybrids were also evaluated in a split plot design under greenhouse conditions at IITA-Namulonge. Results revealed 24 P. zeae susceptible hybrids compared to only six P. zeae resistant hybrids. Grain yield across sites was higher by about 400 kg ha-1 under nematicide treatment than under nematode infestation. The nematode tolerant/resistant hybrids exhibited yields ranging from 5.0 to 8.4 t ha-1 compared to 5.0 t ha-1 obtained from the best check. Grain yield loss was up to 28% among susceptible hybrids, indicating substantial economic yield losses due to nematodes. Under field conditions, desired heterosis was recorded on 18 hybrids for P. zeae, and on three hybrids for Meloidogyne spp. Under nematode infestation, only 16 hybrids had higher relative yield compared to the mean of both checks, the best check and the trial mean, whereas it was 20 hybrids under nematicide treated plots. Overall, most outstanding hybrids under nematode infestation were CML395/MP709, CML312/5057, CML312/CML206, CML312/CML444, CML395/CML312 and CML312/CML395. Therefore, grain yield loss due to nematodes is existent but can be significantly reduced by growing nematode resistant hybrids.
  • Thumbnail Image
    Item
    A New Cheap and Efficient Single-Grain Shatter Tester for Use in Rice Breeding
    (Crop science, 2011) Lamo, Jimmy; Tongoona, Pangirayi; Okori, Patrick; Derera, John; Hendricks, Roelof; Laing, Mark
    Grain shattering, also called grain shedding, is the relative ease with which rice (Oryza sativa L.) seed is dislodged from the pedicel at maturity. Several qualitative methods have been used to assess grain shattering and they tend to underestimate yield loss. Equipments available for quantitative assessment of grain shattering are mostly laboratory based. However, a recently developed prototype in Japan for fi eldwork can be used, but the cost is prohibitive. An improved grain-shattering tester that uses a hand-held device has been developed and reported here. It is an improvement over the stationary laboratory device. It has the following modifi cations: a crocodile clip instead of a bench clamp and a helical spring for testing tensile material instead of tension gauge. The new device is affordable, handy for fi eldwork, and effective for large experimental trials. This equipment was designed and developed at the University of KwaZulu-Natal (UKZN) mechanical workshop (Pietmeritzburg, South Africa). Its effi ciency was tested at the National Crops Resources Research Institute (NaCRRI) at Namulonge, Uganda. The effi ciency was tested by fi rst estimating yield loss in selected test plants using a method that involves shaking panicles. This fi nding was compared with the minimum force required to dislodge the grains using this new device and a high correspondence of R2 = 99.9% was found. This new equipment has therefore been recommended for fi eld assessment of grain shattering.
  • Thumbnail Image
    Item
    Pearl Millet Socioeconomic and Production Characteristics in Uganda
    (National Semi Arid Resources Research Institute, 2015) Lubadde, Geofrey; Tongoona, Pangirai; Derera, John; Sibiya, Julia
    Pearl millet is an important cereal grown by farmers in environmentally marginalised areas. In Uganda it is mainly grown in northern (Acholi), northeastern (Karamoja) and eastern (Teso) regions. The regions are characterised by semi-arid conditions with high temperatures, low mean annual rainfall and widespread chronic food insecurity. Technologies that increase pearl millet productivity under such conditions have been developed in international research institutes to highlight the importance of pearl millet as a resilient crop suitable for drought conditions. However, not much is known about the importance of the crop in Uganda. A baseline survey was thus conducted to document pearl millet farmers’ socioeconomic and production characteristics in the country. Information was collected about demography and food security situation, livelihood, social capital and trainings, importance and utilisation of pearl millet, agronomic characteristics, desirable and undesirable traits, factors of crop and animal production, post-harvest handling, production and marketing constraints and coping strategies. Results indicated that the average age of heads of households (mainly males) was 45.78 years while that of their spouses was 37.22 years; with a pearl millet growing experience of over six years. In addition, majority of the households had 6-10 members many of whom were below 15 years. The heads of households were married with education experience of more than five years while their spouses were generally illiterate. The household heads and their spouses farmed the land as their main economic activity. Furthermore, majority of the households lived under poor conditions where the main house had a single room built of mud and wattle with grass as the main roofing material and earth floor. The poor living standards were worsened by majority of the households facing perpetual food insecurity mainly due to drought, insect pests, plant diseases and lack of improved planting materials.