Abstract
The study of genetic diversity of any germplasm helps to facilitate its use and management. This experiment was carried out to determine the genetic diversity among 87 rice accessions from six countries. Seventeen quantitative traits were recorded based on the internationally accepted standard evaluation system for rice from IRRI. Analysis of variance, principal component analysis (PCA) and correlation amongst quantitative traits were carried out. Highly significant (P<0.001) differences were observed among the accessions for all the quantitative traits. The first five principal components accounted for 75.01% of the total genetic variance among the accessions. Some of the morphological traits had significant positive correlations with grain yield. At 21% similarity coefficient, the 87 accessions from six countries were grouped into seven clusters based on the morpho-agronomic traits. Accessions from these seven clusters have tiller number of 10-20, erect culm angle, no awn, 90-120 days to 50% flowering, semi erect flag leaf, well exserted panicle and grain width of 2-3.5 mm respectively. This experiment has proven that morphological markers are effective in assessing genetic diversity in rice. The genetic diversity revealed by the morpho-agronomic traits in this study would be very important in selecting appropriate genotypes for rice improvement in Africa and elsewhere. Key words: Genetic diversity, morpho-agronomic traits, principal component analysis, rice.
Highlights
Rice (Oryza sativa) is the third highest produced cereal after wheat and maize (FAOSTAT, 2012)
Significant (P
The major goals of rice breeding programmes around the world is to breed for high yield potential, preferred grain quality, and tolerance to abiotic and biotic stresses
Summary
Rice (Oryza sativa) is the third highest produced cereal after wheat and maize (FAOSTAT, 2012). It is the main staple food for about 50% of the world’s population, especially in developing countries (FAO, 2017). By the year 2025, global demand for rice will be 880 million tonnes compared to the current world production of 470 million tonnes of milled rice (IRRI, 2010). The average growth rate of rice yield was 3.68% annually in the 1980s, but it decreased to 0.75% per year in the late. 1990s and rice productions are still low in the world (FAO, 2017). In years to come, expanding the areas of rice cultivation will be limited because of land and water resource scarcity due to climate changes, urbanization and population growth. Pressure from biotic and abiotic factors, declining productivity in intensive rice production systems, increasing the cost of production and low yielding varieties are some of the factors responsible for the low yield of rice obtained by farmers
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