Comparative Analysis Of Genomic Variation And Population Structure Of Rice (Oryza Sativa)

Studying genomic variation and its understanding in cultivated rice (Oryza sativa L.) can help in improving the crop yield by marker assisted selection. The current study was focused on finding the genomic variations among existing cultivated genotypes of Oryza sativa from different countries. Moreover, the study also compares the genomic variation found in Pakistani and International rice genotypes. A total of 95 genotypes were collected from sixteen countries, mainly from Pakistan, India and the Philippines. Evenly distributed 200 Simple Sequence Repeat (SSR) markers were surveyed and 142 SSR markers were found polymorphic, with an average of 4.53 alleles per locus while alleles per marker ranging from 2 to 14. Neighbor joining cluster analysis based on genetic dissimilarity coefficients clearly separated all the genotypes into three groups but being unable to separate the genotypes based on their geographical area reflected their single origin. The IRBL lines from IRRI being part of the aromatic group are the incongruity of results which reflects conserved genome for blast resistance in basmati group. The model-based structure and principal component analysis are in harmony with neighbor joining results. Overall results suggested a narrow genetic variation among rice genotypes taken from different countries. This information obtained from the investigated genotypes will provide a baseline to incorporate preferred variation in future breeding programs to tailor rice genotypes with better stand against unforeseen biotic or abiotic stresses. (C) 2019 Friends Science Publishers