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Analysis of genetic polymorphism in wild Nicotiana species and Cuban cultivated tobacco (Solanaceae) through AFLP

Abstract:

Wild Nicotiana species are commonly used in tobacco's breeding programs to obtain cultivars of enhanced productivity, and to improve its tolerance or resistance to diseases or different types of stress. In Cuba, tobacco production is one of the main sources of economic income and during the last decades several new tobacco varieties have been generated, being essential to study their genetic background for better crop management. In this work, the genetic polymorphism of four Cuban varieties of Nicotiana tabacum L. and six wild species used in Cuban tobacco breeding programs were assessed through AFLP analysis. Polymorphic profiles were obtained with four selective primers combinations (EcoR I/Mse I) among the studied accessions. A total of 203 polymorphic bands (57.79 %) were used for cluster analysis (UPGMA) based on genetic similarity and genetic distance matrices. A common group was detected, comprising all the cultivated varieties that showed high genetic similarity (0.87446-0.93920) according to the Nei and Li's distance measure, whereas wild species showed the highest genetic diversity. It was also possible to identify some bands shared among cultivated accession as specific markers for the analyzed Cuban cultivated tobacco. Our results indicate that AFLP analysis effectively detects the genetic diversity at levels enough to differentiate wild species of Nicotiana from Cuban varieties of N. tabacum, even though a narrow genetic diversity was present in Cuban varieties. All the accessions were distinguished through AFLP analysis.