Characterization of genetic diversity in barley (Hordeum vulgare L.) through DNA fingerprinting

Abstract

Assessment of the extent of genetic variability within a cultivated crop has important consequences in plant breeding and conservation of genetic resources [1]. Barley crop is no exception and therefore, for conservation of its genetic resources and for sustained barley breeding in India, it is important to have knowledge about the availability of genetic variation [1]. Genetic variability between genotypes can be estimated either by determining their levels of polymorphism for genetic markers or by analyzing pedigree relationships. Traditionally, morphological characters have been used to evaluate distinctness, uniformity and stability and also to establish the description of a genotype [2]. However, this method is often influenced by environment and is labour intensive. To overcome these problems, DNA fingerprinting has been established. DNA markers have the advantage that they are virtually unlimited and they do not disturb the physiology of the organism. The PCR (polymerase chain reaction) based methods such as Random Amplified Polymorphic DNA (RAPD) are considered faster and cheaper than non-PCR-based methods. In RAPD, a synthetic oligonucleotide of 9 to 12 bases is used as starting point for DNA amplification with a thermo stable DNA polymerase. In the past, a few studies have indicated the significance of RAPD marker as a tool in establishing genetic diversity and pedigree relationship in barley [3]. However, such studies in Indian germplasm are lacking. Therefore, 26 barley genotypes, which mostly included Indian released cultivars. were used for their genetic characterization using RAPD markers. Seeds of 26 barley genotypes were procured from Barley Improvement Programme of Banaras Hindu University, Varanasi and Directorate of Wheat Research (DWR), Kamal. DNA was extracted from the leaves of each of the 26 genotypes which were grown in the field, using CTAB method [4]. Twenty one RAPD primers procured from Operon Technologies, USA were used (Table 1).