Comparison of genetic diversity determined by different DNA marker systems in wheat genotypes
2013
Iqbal, N.
Simple sequence repeat (SSR) and Inter simple sequence repeats (ISSR) have been routinely used in molecular mapping, phylogenetic studies, DNA finger printing and marker assisted selection (MAS) in wheat (Triticum aestivum). Aim of the present study was identification and Comparison of genetic diversity determined by DNA finger printing technique (ISSR) and locus specific DNA marker (SSR) system. DNA was extracted from sixty four different wheat genotypes including varieties, landraces and synthetic hexaploids which were promising for higher yields and salt stress tolerance. Polymerase Chain Reaction (PCR) analysis has been conducted by using thirty SSR and seven ISSR primers. Thirty Seventy percent SSR primers and 100 percent of ISSR primers generated polymorphic bands across 64 accessions. Total of 129 polymorphic loci were determined by both marker systems. The range of number of polymorphic loci detected ranged from 1 to 4 for SSR and 4 to 12 for ISSR, with an average of 1.6 and 7.9 loci per primer, respectively. PIC value for SSR was calculated for each marker ranged from 0.01 to 0.99 with an average of 0.379; similarly PIC for ISSR was ranged from 0.4 to 0.8 with mean value 0.64. SSR marker BARC-199 and BARC-283 explored maximum diversity (PIC= 0.99) while BARC-320 showed minimum diversity (PIC=0.01) among these 64 genotypes. Average expected heterozygosity was higher for ISSR (0.65) than that of SSR (0.378). Similarly M1 value was also high for ISSR (1.114) than SSR (0.722). At 0.60 coefficients all the wheat genotypes were grouped into three major clusters A. B and C on the basis of both SSR and ISSR DICE similarity coefficients. Greater values for PIC, MI and D suggest ISSRs more suitable marker for genetic diversity estimation.
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