Browsing by Author "Abera Muluneh, Netsanet"

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    Combining Ability Analysis and Determination of Controlling Gene Action for Yield and Other Key Traits of Open Pollinated Maize (Zea Mays L.) Varieties and their Topcrosses with Inbred Line Testers in Uganda
    (Global Journal of Agricultural Research, 2020) Abera Muluneh, Netsanet; Lapaka Odong, Thomas
    The study was carried out with 38 top crosses which were evaluated with parents and checks. The objective of the study was to determine combining ability and the type of controlling gen action for yield and yield related traits of 19 OPVs using their top crosses in terms of grain yield, days to anthesis, plant height and grain texture. Line x tester analysis result of mean squares of ANOVA revealed statistically significant interaction of genotypes (female, male and crosses) with environment variations for selected traits under study. Baker’s ratio of 1.00 for grain yield, suggests that additive genes were highly most important than nonadditive for the control of yield. The higher value of broad sense coefficient of genetic determination (H) was high for yield, days to anthesis, plant height and grain texture. Female parent KC2014 and male parent inbred line TA (CML536) had significantly positive GCA effect for grain yield. These parents were the best general combiners for grain yield across sites. Similarly, female parent OPVs (MM3, Longe 5, Longe 5D, SITUKA MI and VP MAX) and male parent inbred line TB (CML202) had highly significant negative GCA for days to anthesis, indicated that these parents can breed for earliness. Therefore, the exhibited variations between OPVs in terms of the GCA and SCA effects can be exploited to produce topcrosses which will help in selection of parents for hybrid development and variety improvement.
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    Yield Stability Analysis of Open Pollinated Maize (Zea mays L.) and their Topcross Hybrids in Uganda
    (World Scientific News, 2018) Abera Muluneh, Netsanet; Lapaka Odong, Thomas; Kasozi, Lwanga Charles; Edema, Richard; Gibson, Paul; Koime, Daniel
    The study was aimed at determining yield stability and adaptability patterns of a set of 65 open pollinated maize genotypes evaluated across four different agro ecologies in Uganda using 5 × 13 α-lattice design replicated twice. Individual location analysis ANOVA results showed mean squares of genotype were statistically highly significant in terms of days to 50% anthesis, anthesis silking interval, grain yield and maize streak virus disease severity score for all environments tested except for grain yield in Ngetta. The highest grain yield was recorded for topcross C9/TA (ECAVL1/CML536) of 9.60 t ha-1 in Bulindi, for top cross C3/TA (Longe5/CML536) of 9.56 t ha-1 in Namulonge. However, they were quite unstable as their ranking was not consistent across environments. The genotype Ambsyn5, C4/TB, FS85 and C9/TB were showed the lowest disease score for MSV. The parent OPV SITUKA MI was with the lowest day requirement for shading pollen and hence it can be utilized in breeding for earliness. The additive main effects and multiplicative interaction (AMMI) analysis results indicated that the tested genotypes were highly influenced by genotype main effects, environment effects and genotype x environment interaction effects; the magnitude of environment and its interaction effect for grain yield was 9.8 times greater than the variation attributed to genotype main effects thus these genotypes were more affected by the environment and their interaction. Based on Finlay and Wilkinson’s sensitivity estimate, genotypes G40, G58, G42, G44, G56, G23, G52 and G53 were identified as the most stable and widely adaptable.