Study of genetic and molecular diversity in a collection of indigenous aromatic rice (Oryza sativa L.)
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Date
2004-07
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
Rice comprising of 22 wild and two cultivated species (O. sativa and O. glaberrima) is the staple food for more than one- third of the world populace. In recent years, there has been an increased number of genetically related varieties released by rice breeders which has resulted in limited levels of genetic diversity. Information on the extent of genetic diversity among accessions is needed to harness the germplasm and thus, make use of the available genetic resources to create new accessions. Therefore, the present investigation of “Study of genetic and molecular diversity in a collection of indigenous aromatic rice” was carried out in aromatic rice to study genetic diversity through Mahalanobis D2 statistic and Microsatellite or simple sequence repeat markers. Forty indigenous aromatic rice genotypes and one non- aromatic check displayed considerable diversity on agromorphological data and quality traits. On the basis of Mahalanobis D2 statistic ten clusters were formed. Cluster I comprised of 13 genotypes, cluster II had 12 and cluster III and IV contained five genotypes. Cluster V, VI, VII, VIII, IX and X contained one genotype each. It was found that geographical diversity need not necessarily be related to the genetic diversity.
Molecular diversity delineated by 15 microsatellite (SSR) markers revealed high level of divergence. A total of 83 bands were amplified of which 79 were polymorphic. The dendrogram generated from data derived from fragments amplified by primers clearly separated the aromatic group of rice from non- aromatic check Pant Dhan- 12. Aromatic rice genotypes were classified in two groups, cluster I had 2 and 38 genotypes were there in cluster II. But clusters generated by D2 statistic were not able to distinguish the non- aromatic check instead it was grouped with 12 other aromatic rice genotypes in the cluster II. Thus, information content generated by microsatellite markers was more valuable. The hybridization between the genotypes falling in most distant clusters is expected to result in maximum hybrid vigor and higher number of useful segregates.
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