Seed and grain quality characteristics of some rice varieties in Ghana

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Forty six rice varieties, (34 from Crop Research Institute in Kumasi, Ghana and 11 from WARDA and 1 from Ivory Coast) were evaluated for their seed and grain quality. These varieties were multiplied at the Nobewam rice multiplication center in the Ashanti Region, Ghana. Forty five days after harvesting, the seeds were tested for their milling quality, pasting characteristics and germination and vigor percentages. Grain length, length to width ratio and the thousand hulled and milled rice grain weights were also determined. Based on the thousand hulled grain weights, the varieties were categories into five ranges; 27-30grams, 30-33grams, 33-36grams, 36-39grams and above 39grams. The hulled grain length were classified into three, as very long (32), long (12) and medium (2). Based on the width, the hulled grains were also classified as semi-spherical (39 varieties). Using the data on the length and length to width ratio of the milled rice grains, the varieties were classified as extra long (33 varieties), long (12 varieties) and medium (1 variety). They were further classified base on their length to width ratio as slender (27 varieties). From the germination and vigor tests, eleven varieties had good vigor percentages (above 80%). The varieties performed differently during the milling test. Of the forty six varieties rice varieties tested for the milling performance, twenty nine varieties were categorized as grade 1 among the head rice percentage varieties. For pasting characteristics, the breakdown viscosities ranged from 0.0 BU to 71.0 BU. Based on the breakdown viscosity values, the varieties were categorized into three groups; low (≥0≤10.9BU) 29 varieties, intermediate (≥11≤19.9BU) 5 varieties and high (≥20BU) 12 varieties. The time used by the varieties to reach gelatinization temperature ranged from 17. 53 minutes to 29.18 minutes. Based on the parameters studied, 29 varieties are recommended for distribution to farmers to increase the number of varieties that farmers and consumers have to choose from.
A Thesis submitted to the Department of Horticulture, Faculty of Agriculture, College of Agriculture and Natural Resources of the Kwame Nkrumah University of Science and Technology, in partial fulfillment of the requirements for the degree of Master of Science in Seed Science and Technology.