Genetic diversity in Liberian and Ghanaian rice (Oryza Sativa l., Oryza Glaberrima Steudei) Germplasm using morphological and simple sequence repeat (SSR) markers.

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November, 2016
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Rice is an important staple food crop that feed over half of the global population and it has become the cereal that provides a major source of calories for the urban and rural poor in Africa. However, little attention has been paid to the improvement of Liberian and Ghanaian rice germplasm evaluation and the genetics of some quality traits. The need for increasing rice cultivation depends not only on cultural/traditional practices but also on their inbuilt genetic potential to withstand stresses. Therefore, these varieties have to be collected and evaluated for their exploitable genetic variability and conserved. The first step in achieving this is to evaluate and characterize available rice germplasm or genotypes at both morphological and molecular levels to reveal important traits or accessions of interest to plant breeders for crop improvement. In experiment, arranged in Completely Randomized Design was conducted to study the genetic variability among and within 48 genotypes or accessions obtained from Central Agricultural Research Institute (CARI), Suakoko, Liberia and Plant Genetic Resources Research Institute (PGRRI), Bunso, Ghana. DNA was extracted from 48 plants per accession without bulking to check the purity of the accession using the 16 SSR markers. Field data taken included 28 qualitative and 14 quantitative traits scored using the IRRI descriptor list. Analysis of variance revealed highly significant difference (P≤ 0.01) among the accessions for all quantitative traits studied except for grain width. Qualitative data revealed some variations among the traits. Four significant principal components analysis were identified and accounted for 55.3%. PC1 had Eigen-value of 0.44 explaining 18.5% of the total variation. Next was PC2 which had 0.31 as its Eigen-value, explained 14.5% to the total variation. Correlation analysis indicated that length of ligule was highly significant and positive with leaf width of blade. Similar observation was made with grain length and length of ligule. The SSR markers were highly informative as generated by the powerMarker V3.25 software. At the iii similarity coefficients 90%, the highly distance genetic diversity was found between two accessions, ACSS37 and ACSS1. Cluster X was the largest of all the clusters while Clusters VII and VIII were the second largest clusters with 7 accessions each. The outcome of this study should be useful to manage the gremplasm conservation and future rice genetic improvement. However, all the accessions may be cultivated over time at different locations on the field to ascertain their stability and purity.
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A Thesis submitted to the Department of Crop and Soil Sciences, Faculty of Agriculture, Kwame Nkrumah University of Science and Technology, in partial fulfillment of the Requirements for the degree of Master of Philosophy in Agronomy (plant breeding)
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