Browsing by Author "Yoseph Beyene"

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Efficacy of Event MON 87460 in drought-tolerant maize hybrids under optimal and managed drought-stress in eastern and southern africa
(Journal of Genetic Engineering and Biotechnology, 2024-02-12) Caleb O. Obunyali; Kiru Pillay; Barbara Meisel; Eric N. Ndou; Kingstone Mashingaidze; Julius Pyton Sserumaga; Godfrey Asea; Murenga Mwimali; Regina Tende; Yoseph Beyene; Stephen Mugo; Emmanuel Okogbenin; Sylvester O. Oikeh
Background: Frequent drought events due to climate change have become a major threat to maize (Zea mays L.) production and food security in Africa. Genetic engineering is one of the ways of improving drought tolerance through gene introgression to reduce the impact of drought stress in maize production. This study aimed to evaluate the efficacy of Event MON 87460 (CspB; DroughtGard®) gene in more than 120 conventional drought‐tolerant maize hybrids in Kenya, South Africa, and Uganda for 3–6 years under managed drought‐ stress and optimal conditions and establish any additional yield contribution or yield penalties of the gene in traited hybrids relative to their non‐traited isohybrids. Germplasm used in the study were either MON 87460 traited un‐adapted (2008–2010), adapted traited DroughtTEGO® (2011–2013) or a mix of both under confined field trials. Results: Results showed significant yield differences (p < 0.001) among MON 87460 traited and non‐traited hybrids across well‐watered and managed drought‐stress treatments. The gene had positive and significant effect on yield by 36–62% in three hybrids (CML312/CML445; WMA8101/CML445; and CML312/S0125Z) relative to non‐traited hybrids under drought, and without significant yield penalty under optimum‐ moisture conditions in Lutzville, South Africa. Five traited hybrids (WMA2003/WMB4401; CML442/ WMB4401; CML489/WMB4401; CML511/CML445; and CML395/WMB4401) had 7–13% significantly higher yield than the non‐traited isohybrids out of 34 adapted DroughtTEGO® hybrids with same background genet- ics in the three countries for ≥ 3 years. The positive effect of MON 87460 was mostly observed under high drought‐stress relative to low, moderate, or severe stress levels. Conclusion: This study showed that MON 87460 transgenic drought tolerant maize hybrids could effectively tolerate drought and shield farmers against severe yield loss due to drought stress. The study signified that development and adoption of transgenic drought tolerant maize hybrids can cushion against farm yield losses due to drought stress as part of an integrated approach in adaptation to climate change effects.
Genetic trends for yield and key agronomic traits in pre- commercial and commercial maize varieties between 2008 and 2020 in Uganda
(Frontiers, 2023-03-10) Godfrey Asea; Daniel Bomet Kwemoi; Clay Sneller; Charles L. Kasozi; Biswanath Das; Lennin Musundire; Dan Makumbi; Yoseph Beyene; Boddupalli M. Prasanna
Estimating genetic gains is vital to optimize breeding programs for increased efficiency. Genetic gains should translate into productivity gains if returns to investments in breeding and impact are to be realized. The objective of this study was to estimate genetic gain for grain yield and key agronomic traits in pre- commercial and commercial maize varieties from public and private breeding programs tested in (i) national performance trials (NPT), (ii) era trial and, (iii) compare the trends with the national average. The study used (i) historical NPT data on 419 improved maize varieties evaluated in 23 trials at 6-8 locations each between 2008 and 2020, and (ii) data from an era trial of 54 maize hybrids released between 1999 and 2020. The NPT data was first analyzed using a mixed model and resulting estimate for each entry was regressed onto its first year of testing. Analysis was done over all entries, only entries from National Agricultural Research Organization (NARO), International Maize and Wheat Improvement Center (CIMMYT), or private seed companies. Estimated genetic gain was 2.25% or 81 kg ha-1 year-1 from the NPT analysis. A comparison of genetic trends by source indicated that CIMMYT entries had a gain of 1.98% year-1 or 106 kg ha-1 year-1. In contrast, NARO and private sector maize entries recorded genetic gains of 1.30% year-1 (59 kg ha-1 year-1) and 1.71% year-1 (79 kg ha-1 year-1), respectively. Varieties from NARO and private sector showed comparable mean yields of 4.56 t ha-1 and 4.62 t ha-1, respectively, while hybrids from CIMMYT had a mean of 5.37 t ha-1. Era analysis indicated significant genetic gain of 1.69% year-1 or 55 kg ha-1 year-1, while a significant national productivity gain of 1.48% year-1 (37 kg ha-1 year-1) was obtained. The study, thus, demonstrated the importance of public-private partnerships in development and delivery of new genetics to farmers in Uganda.
Genetic trends in CIMMYT’s tropical maize breeding pipelines
(Nature Journal, 2022-11-22) Boddupalli M. Prasanna; Juan Burgueño; Yoseph Beyene; Dan Makumbi; Godfrey Asea; Vincent Woyengo; Amsal Tarekegne; Cosmos Magorokosho; Dagne Wegary; Thokozile Ndhlela; Mainassara Zaman‐Allah; Prince M. Matova; Kabamba Mwansa; Kingstone Mashingaidze; Pedro Fato; Adefris Teklewold; B. S. Vivek; P. H. Zaidi; M. T. Vinayan; Nagesh Patne; Sujay Rakshit; Ramesh Kumar; S. L. Jat; S. B. Singh; Prakash H. Kuchanur; H. C. Lohithaswa; N. K. Singh; K. B. Koirala; Salahuddin Ahmed; Felix San Vicente; Thanda Dhliwayo; Jill E. Cairns
Fostering a culture of continuous improvement through regular monitoring of genetic trends in breeding pipelines is essential to improve efficiency and increase accountability. This is the first global study to estimate genetic trends across the International Maize and Wheat Improvement Center (CIMMYT) tropical maize breeding pipelines in eastern and southern Africa (ESA), South Asia, and Latin America over the past decade. Data from a total of 4152 advanced breeding trials and 34,813 entries, conducted at 1331 locations in 28 countries globally, were used for this study. Genetic trends for grain yield reached up to 138 kg ha−1 yr−1 in ESA, 118 kg ha−1 yr−1 South Asia and 143 kg ha−1 yr−1 in Latin America. Genetic trend was, in part, related to the extent of deployment of new breeding tools in each pipeline, strength of an extensive phenotyping network, and funding stability. Over the past decade, CIMMYT’s breeding pipelines have significantly evolved, incorporating new tools/technologies to increase selection accuracy and intensity, while reducing cycle time. The first pipeline, Eastern Africa Product Profile 1a (EA-PP1a), to implement marker-assisted forward-breeding for resistance to key diseases, coupled with rapid-cycle genomic selection for drought, recorded a genetic trend of 2.46% per year highlighting the potential for deploying new tools/technologies to increase genetic gain.
Performance of Bt maize event MON810 in controlling maize stem borers Chilo partellus and Busseola fusca in Uganda
(Crop Protection, 2022-06-05) Michael H. Otim; Simon Alibu; Godfrey Asea; Grace Abalo; Julius Pyton Sserumaga; Stella Adumo; Jane Alupo; Stephen Ochen; Tadele Tefera; Anani Y. Bruce; Yoseph Beyene; Barbara Meisel; Regina Tende; Francis Nang’ayo; Yona Baguma; Stephen Mugo; Sylvester O. Oikeh
Stem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda.