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Genetic diversity analysis aiding in selection of parents to generate mapping population revealed by molecular markers in rice

Immanuel Selvaraj Chinnadurai, Pothiraj Nagarajan, Krishnan Thiyagarajan, Marudappan Bharathi

Genetic diversity among 26 rice genotypes from different geographical origin was investigated using molecular markers. The genotypes were screened for the leaf blast disease reaction at two different hot spot environments. The disease reaction scores were compared with the clustering pattern. Themeanmarker index (MI) for the primerswas 2.082. The average pair wise similarity values based on their geographical origin revealed that the South East Asian genotypes had the highest value of 0.664, followed by (0.604) SouthAsian genotypes.Most of the pair wise comparisons fell into the similarity range of 0.601-0.700. Clustering based on dendrogram revealed two major clusters and 5 sub clusters. The South East Asian genotypes and South Asian genotypes clustered together in all branches of dendrogram indicating that both groups were diverse, except the major cluster ‘2’consisted all of three SouthAsian varieties. In Principal Coordinate Analysis (PCoA), the first three coordinates, accumulated 98.06 per cent of total variation. PCoA revealed threemajor groups. The first coordinate does not discriminate any of the genotypes based on the geographical origin, but the second and third coordinates differentiated South East Asian and South Asian genotypes clearly. Genetic diversity analysis of rice genotypes with RAPD marker system and phenotypic screening for blast resistance revealed thatWhite Ponni (susceptible) andMoroberekan (resistant) were genetically distant and contrasting parents for leaf blast resistance for mapping population development. There is a partial discrimination of the RAPD markers to distinguish leaf blast resistant and susceptible genotypes into separate clusters by the principal coordinate analysis.