Assessment of genetic diversity in different types of tobacco using molecular markers

Information about the amount of genetic diversity in the germplasm and genetic relations of genotypes is essential for analyzing and designing breeding programs and could be used for assisting in genetic identification and improvement of the germplasm. In this research, the genetic diversity of 48 genotypes of the flue-cured, burley, and oriental types of tobacco was investigated by 12 ISSR, 10 SSR, and five IRAP primers. The maximum number of bands was observed in the UBC825, RTR-10, and mixed primer UBC817 + UBC826 with 17 bands, UBC817 with 16 bands, and RTR-8 with 15 bands. UBC824 with 10 and UBC823 with 11 bands showed the minimum number of bands among ISSR and IRAP primers, and PT30044 and PT30046 primers with two alleles showed the minimum number of alleles among SSR markers. In ISSR and IRAP, the observed percentage of polymorphism ranged from 76.92% for RTR-1 and RTR-7 to 94.11% for RTR-10, and in SSR markers, it was 100%. The average polymorphism percentage was 90.7%, which indicated suitable genetic diversity among the tobacco genotypes. The polymorphism information content ranged from 0.31 to 0.5 with an average of 0.42. The average diversity of Nei and Shannon indices were 0.39 and 0.58, respectively. Cluster analysis by the UPGMA method classified the 48 tobacco genotypes into five groups, containing 5, 12, 10, 6, and 15 genotypes, respectively. Principal coordinate analysis showed that the 14 first components could explain 51.49% of the total variance. The primers used in this study had high efficiency, which can be used to study the genetic diversity in tobacco.