Evaluation of Maize ( Zea mays L .) Genotypes for High Grain Yield and Resistance to Maize Streak Virus Infections under Diverse Agro-Ecological Zones

Background: Maize streak disease (MSD), caused by maize streak virus (MSV) is the most serious biotic constraint to maize (Zea mays L.) production in subSaharan Africa, threatening food security and incomes of farmers in the region. Under field conditions, the disease can cause up to 100% yield loss, depending on maize genotype and plant age at the time of infection.
Materials and methods: Field trials were established at Ohawu, Kpeve and Nkwanta representing coastal savannah, forest and forest-savannah transition agroecological zones (AEZs) respectively of the Volta region of Ghana during 2015 minor season to evaluate 16 maize genotypes for high yielding and resistance to maize streak virus (MSV) infection. The fields were laid out in a Randomised Complete Block Design (RCBD) with four replocations. The plants were scored for disease severity at 10 weeks after planting (WAP) based on a 1-5 visual scale (1=no infection and 5=very severe infection). Both disease and agronomic data were subjected to analysis of variance (ANOVA) using GenStat Release version 12 statistical package.
Results: The study revealed significant varietal, locational and genotype x location interaction effect (p<0.05) on mean MSD severity scores and grain yields. Mean MSD severity scores were highest at Nkwanta, followed by Kpeve and the lowest at Ohawu. The improved varieties Abontem, Aburohemaa, Akposoe, Dorke, Etubi, Honampa, Omankwa, Obatanpa, PAN 12, and the breeding lines CRI001, CRI002, CRI003, CRI004, CRI005 and CRI006 displayed mild MSD symptoms and also had higher yields compared to Dzinu-Eve (a local cultivar). However, the
study revealed significant genotype x location interaction effect (p<0.05), with Akposoe, Etubi, Honampa and PAN 12 showing higher MSD symptom severity scores at Kpeve than at Nkwanta and Ohawu, whereas the other 12 maize genotypes had higher mean MSD severity scores at Nkwanta than Kpeve and Ohawu.
Conclusion: The maize genotype and locations have significant influence on the level of disease severity and grain yields. Therefore, maize genotypes that showed mild symptoms of MSD and also gave high grain yields should be further evaluated and released as varieties for the locations where they performed better.
 

Author(s): Elvis Asare-Bediako, Kingsley J Taah J, Grace van der Puije, Godwin Amenorpe, Anthony Appiah-Kubi and Samuel Akuamoa-Boateng S

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