Browsing by Author "Kagoda, Frank"

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    Genotype by environment interaction effects on grain yield of highland maize (Zea mays L) hybrids
    (Maydica, 2018) Ninsiima Kayaga, Hellen; Ochwo-Ssemakula, Mildred; Kagoda, Frank; Mahulé Elysé Alladassi, Boris; Asea, Godfrey; Gibson, Paul; Edema, Richard
    Maize varieties adapted to highland environments are generally scarce in East and Central Africa (ECA) since most breeding efforts have focused on mid-altitude maize. As a result, farmers in the highlands of Uganda mainly grow varieties that are bred for the mid-altitude zones. Since these maize varieties are not adapted to highland conditions, their productivity in this region rarely exceeds 2 t ha-1. This study was aimed at determining the effect of genotype by environment interactions (GEI) on the grain yield of highland maize hybrids. The study was conducted in three highland locations of Uganda in the maize growing season of March to October 2015. Thirty-six F1 hybrids and two checks were arranged in a 2 x18 (0, 1) alpha lattice design with two replications. Hybrid by location interaction had highly significant differences (P ≤ 0.001) and explained 46.2% of phenotypic variance. Genotype by environment interactions (GEI), thus, had a strong effect on grain yield. Analyses revealed two maize megaenvironments, with AMH701-9/AMH703-22 hybrid emerging the best genotype in Kachwekano and Kalengyere (6.69 t ha-1 and 14.30 t ha-1), and AMH701-9/AMH701-20 hybrid being the best in Buginyanya (14.39 t ha-1). Efforts to breed for high yielding maize cultivars for the highland areas of Uganda should therefore focus more on specific adaptation than broad adaptation.
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    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.
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    Inheritance of Yield and Yield-related Traits in Highland Maize Hybrids of Uganda
    (Journal of crop science and biotechnology, 2017) Ninsiima Kayaga, Hellen; Kagoda, Frank; Ochwo-Ssemakula, Mildred; Mahulé Elysé Alladassi, Boris; Asea, Godfrey; Gibson, Paul; Edema, Richard
    Although many studies have been conducted on gene action of grain yield and yield related traits in maize, none of them focused on highland maize in Uganda. This study was conducted to establish the gene action controlling inheritance of yield and its related traits in highland maize hybrids. Thirty-six F1 hybrids generated from a 9 x 9 half diallel mating design, were planted with two local checks in three highland locations; Kalengyere, Kachwekano, and Buginyanya with two replications using a 2 x 19 alpha (0, 1) lattice design. Results showed that inheritance of ear length and anthesis-silking interval was controlled by both additive and non-additive gene action while the inheritance of days to anthesis, days to silking was mainly controlled by additive gene action. The inheritance of grain yield and other yield related traits was greatly influenced by environment and genotype x environment interaction. Considering the great influence of the environment and genotype x environment interaction on most of the traits including grain yield, further testing in additional locations over more seasons and broadening the genetic base of the parents is encouraged.