Person:
Asea, G.

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Asea
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Asea, G.

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Now showing 1 - 10 of 12
  • Genetic trends for yield and key agronomic traits in pre-commercial and commercial maize varieties between 2008 and 2020 in Uganda
    (Frontiers, 2023) Asea, G.; Kwemoi, D.B.; Sneller, C.; Kasozi, C.L.; Das, B.; Musundire, L.; Makumbi, D.; Beyene, Y.; Prasanna, B.M.
    Publication
  • Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda
    (Elsevier, 2022) Otim, M.; Alibu. S.; Asea, G.; Abalo, G.; Sserumaga, J.P.; Adumo, S.; Alupo, J.; Ochen, S.; Tadele Tefera; Bruce, A.Y.; Beyene, Y.; Meisel, B.; Tende, R.; Nang’ayo, F.; Baguma, Y.; Mugo, S.N.; Oikeh, S.O.
    Publication
  • Genetic trends in CIMMYT’s tropical maize breeding pipelines
    (Nature Publishing Group, 2022) Prasanna, B.M.; Burgueño, J.; Beyene, Y.; Makumbi, D.; Asea, G.; Woyengo, V.; Tarekegne, A.T.; Magorokosho, C.; Dagne Wegary Gissa; Ndhlela, T.; Zaman-Allah, M.; Matova, P.M.; Mwansa, K.; Mashingaidze, K.; Fato, P.; Chere, A.T.; Vivek, B.; Zaidi, P.; Vinayan, M.T.; Nagesh, P.; Rakshit, S.; Kumar, R.; Jat, S.L.; Singh, S.B.; Kuchanur, P.; Lohithaswa, H.C.; Singh, N.K.; Koirala, K.B.; Ahmed, S.; San Vicente Garcia, F.M.; Dhliwayo, T.; Cairns, J.E.
    Publication
  • On-farm performance and farmers’ participatory assessment of new stress-tolerant maize hybrids in Eastern Africa
    (Elsevier, 2020) Regasa, M.W.; De Groote, H.; Munyua, B.G.; Makumbi, D.; Owino, F.; Crossa, J.; Beyene, Y.; Mugo, S.N.; Jumbo, M.B; Asea, G.; Mutinda, C.J.M.; Kwemoi, D.B.; Woyengo, V.; Olsen, M.; Prasanna, B.M.
    Publication
  • Breeding WEMA maize for the African Continent
    (CIMMYT, 2018) Mugo, S.N.; Beyene, Y.; Ndou, E.; Oikeh, S.O.; Asea, G.; Mashingaidze, K.
    Publication
  • Correction to: genotype by environment interactions and agronomic performance of doubled haploids testcross maize (Zea mays L.) hybrids
    (Springer, 2018) Sserumaga, J.P.; Oikeh, S.O.; Mugo, S.N.; Asea, G.; Otim, M.; Beyene, Y.; Abalo, G.; Kikafunda, J.
    Publication
  • Genetic analysis of tropical midaltitude-adapted maize populations under stress and nonstress conditions
    (Crop Science Society of America (CSSA), 2018) Makumbi, D.; Assanga, S.; Diallo, A.O.; Magorokosho, C.; Asea, G.; Regasa, M.W.; Banziger, M.
    Maize (Zea mays L.) yield in sub-Saharan Africa (SSA) is low because of both abiotic and biotic constraints, and limited availability or use of improved seed in some areas. This study was conducted (i) to estimate combining ability and heterosis among seven stress-tolerant populations, and (ii) to assess diversity among the populations and the relationship between diversity and heterosis. Twenty-one hybrids developed from diallel crosses of seven populations, parents, and two checks were evaluated in 10 optimal and 11 stressed environments (drought, low N, and random stress) in Kenya, Ethiopia, Uganda, and Zimbabwe for 2 yr. Analysis II of Gardner and Eberhart showed that variety and heterosis were significant for grain yield (GY) under optimal and managed stress, and across environments. Heterosis accounted for most of the variation for GY among populations under optimal conditions (67%) and drought stress (53%), which suggested the importance of dominance in inheritance of GY under these conditions. Genetic distance (GD) among populations ranged from 0.328 to 0.477 (mean = 0.404). The correlation between GD and heterosis was low (r = 0.14-0.40) in all environments. The simple sequence repeat (SSR) marker-based and GY-based clustering of parental populations showed similar patterns, with three populations distinct from the rest, suggesting significant differentiation of allelic variation in these three populations. The SSR-based diversity and phenotypic analysis results should be useful in defining breeding strategies and maintaining heterotic patterns among these populations.
    Publication
  • Grain yield performance and flowering synchrony of CIMMYT’s tropical maize (Zea mays L.) parental inbred lines and single crosses
    (Springer, 2016) Regasa, M.W.; Makumbi, D.; Beyene, Y.; Das, B.; Mugo, S.N.; Pixley, K.V.; Banziger, M.; Owino, F.; Olsen, M.; Asea, G.; Prasanna, B.M.
    Maize production constraints in sub-Saharan Africa (SSA) are being addressed by CIMMYT and partners through an array of projects, focusing on developing and evaluating parental inbred lines and single-crosses as well as formulating, evaluating and releasing high-yielding and stress resilient hybrids adapted to different agro-ecologies. The objectives of the present study were to (1) evaluate the grain yield performance of parental elite inbred lines developed over the years, and single crosses; and (2) ascertain the flowering synchrony among inbred lines and single-cross hybrid parents. Parental inbred lines and single-crosses were evaluated at seven locations in two countries in 2014. Combined analysis of variance revealed differences (P < 0.01) among genotypes for grain yield (GY) and among different years/era of release of the inbred lines. The improvement in GY of inbred lines was estimated to be 1.4 % per year. Under irrigated conditions GY of some single-cross hybrids was over 16 t ha−1. Some single-cross and inbred line parents showed acceptable flowering synchrony, good producibility, and stable performance across testing environments, suggesting that these have high potential for seed production. Further research is needed to determine the physiological and morphological characteristics that contributed to the GY improvement in the parental inbred lines. Information generated from this study will enhance the use of CIMMYT’s tropical mid-altitude parental germplasm by breeders working in both private and public breeding programs for developing and deploying high-yielding maize hybrids for the benefit of small-scale farmers in SSA.
    Publication
  • Molecular characterization of tropical maize inbred lines using microsatellite DNA markers
    (Consiglio per la Ricerca e la sperimentazione in Agricoltura, Unità di Ricerca per la Maiscoltura, 2014) Sserumaga, J.P.; Makumbi, D.; Ji, H.; Njoroge, K.; Muthomi, J.; Chemining’wa, G.N.; Si-myung, L.; Asea, G.; Kim, H.
    An insight on diversity and relationships among germplasm is important in any breeding program for crop improvement. The main objectives of our study were to: (i) determine the level of genetic diversity within mid altitude maize inbred lines resistant to weevils, aflatoxin accumulation and drought, (ii) to suggest potential heterotic groups using their genetic structures and distance based on cluster analysis with the aim to generate broad based source germplasm for mid altitude maize breeding program with combined traits of importance against Aflatoxin accumulation. In this study, 25 SSR markers were used to finger print forty two maize inbred lines to assess the genetic diversity, genetic relationships, and their population structure. A total of 184 alleles were identified at all the loci with an average of 7.36 and a range between two and 19 alleles per locus. The major allele frequency varied from 0.17 to 0.90 with an average of 0.49 while the minor allele frequency varied from 0.10 to 0.83 with an average of 0.51. The gene diversity values varied from 0.18 to 0.92 with an average of 0.65. Average heterozygosity percentage of the inbred lines was 4%, ranging from 0% to 2%, indicating the low level of heterozygosity within the inbred lines. The average polymorphism information content (PIC) was 0.61. A dendrogram constructed using unweighted Neighbour Joining algorithm suggested three heterotic groups among the inbred lines. The three heterotic patterns based on the SSR markers need to be verified by field testing to confirm what appears to be promising alternative heterotic patterns. The fixed pattern detected using SSR markers could potentially contribute towards effective utilization of the inbred lines for the exploitation of heterosis and formation of genetically diverse sources population.
    Publication
  • Maize variety options for Africa: Uganda
    (CIMMYT, 2015) Abate, T.; Makumbi, D.; Regasa, M.W.; Asea, G.; Wawa, B.
    Maize is the most important cereal in Uganda. Annual rates of growth for area, yield and production were 4.5%, 4.0% and 8.9%, respectively, between 2000 and 2013. Improved maize variety releases in Uganda between 2007 and 2014 grew by 46% in comparison to the 2000 to 2006 period. Hybrid turnover in Uganda is 11 years (one of the shortest in SSA) and OPVs have 16 years. The use of hybrids is increasing at a fast rate. Variety releases have been tailored to fit the capacity of national seed companies – companies with adequate capacity were licensed more sophisticated hybrids whereas smaller companies were given less complex top crosses.
    Publication