Seed maize (Zea Mays l.) quality factors from five agroecological zones in Ghana and their impact on growth and grain yield

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Maize (Zea mays L.) is a staple cereal food crop and is cultivated in different agro-ecological zones of Ghana. However, its yield is very low compared to the crop potential. There are constraints on yield, out of which uncertified and low-quality seeds is the most important one. Seed quality evaluations of maize seeds produced under certified and farmer-saved seed systems from five agro-ecological zones of Ghana have been done in 2015 minor season. Seed purity analysis and fungus identifications were conducted in the Pathology lab, Department of Crop and Soil sciences using randomized complete design in three replications. 1000g of working maizseed samples was also taken from submitted samples and then sorted into pure, broken, discoloured, shriveled, and pets damaged seeds by visual examination. The components were weighed using an electronic weighing balance. Four hundred maize seeds were selected from pure seed samples under both seed systems and planted on trays filled with moistened sterilized river sand in a randomized complete design with four replications at the plant house. After seven days seedlings were counted and sorted out into normal, abnormal seedlings, ungerminated, and dead seeds. Ten seeds were selected randomly from pure seed samples and socked in distilled water for 24h and then separated in to endosperm, cotyledon, and embryo. The components were plated on Petridishes half-filled with PDA and after seven days fungi identifications were done using a compound microscope and the help of identification manual (Hunter and Barnett, 1978). Data on seed purity analysis, germination tests, and fungus infection were collected. Field trial was done after the land was slashed by cutlass, ploughed and harrowed. The experiment was done 2x5 factorial randomized complete block design with four replications at the spacing of 80x40 cm with three seeds per hill one seedling thinned later two weeks after planting. Data on seedling emergence, number of plants per m2 , measurements of plant height at 20, 40, 60, 80, 100 days after planting, days to silk, days to tassel, maturity date, and yields were collected. The data were analyzed by Genstat statistical package software (ver. 12) and means were separated by least significant difference at 5%. The laboratory purity analysis results showed that, seeds from certified seed system gave higher percent value than farmer-saved seed system. Coastal Savannah 95.10%, Semi-deciduous 94.57%, Transitional 94.53%, Guinea Savannah 94.13%, and Rainforest zones 93.73% respectively. In addition the germination tests were showed that, certified seed system was recorded the highest normal seedlings across the study zones. The maximum mean yield was from certified seed from the Guinea Savanna zone (664kg/ha) and the minimum value was observed in farmer-saved seed from the Transitional zone (390.5kg/ha). The study realized that seed quality parameters have an impact on emergence, growth, and grain yields of maize. To maintain optimal plant population and increase maize yield, certified seeds should be available to the farmers. And also strengthen farmers' capacity in seed production and postharvest handling of the seeds. However, further study of the variety across different locations and under farmer conditions are recommended.
A thesis submitted to The Department of Horticulture, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology Kumasi in partial fulfilment of the requirements for the award of a Master of Philosophy Degree in Seed Science Technology, 2016