PHYLOGENETIC RELATIONSHIPS OF ONION (Allium cepa L.) CULTIVARS BY SEQUENCING OF THE ITS REGION

The study of the phylogenetic relationship of onion cultivars with the Institute Agronomic of Pernambuco-IPA designation in the state of Pernambuco is of great interest as a tool to aid in the improvement of this culture. Four cultivars (IPA7, IPA10, IPA12, and VCE (cultivar in testing)) were analyzed using both Nuclear ribosomal internal transcribed spacer ((ITS1 and ITS2). Two major groups were observed in the phylogenic tree. (1) A group formed by the IPA series cultivars and Allium cepa (AM 418367.1), A. vavilovii x A. cepa (AM 418366.1) and A. vavilovii (AM 418363.1) accessions from GenBank subdivided into three subgroups: 1.1, a group with affinity to A. asarense (AM 418365.1); 1.2, a group with affinity to A. roylei (AM 492189.1) and A. farctum (AM 492190.1); 1.3, a group with affinity to A. fistulosum (AM 418372.1); and 1.4, a group with affinity to A. rupestristepposum (AJ411869.1). (2) A group formed by Ophrys ferrum-equinum, an external member (AM 711829.1) of the order Asparagales. The IPA7, IPA10, IPA12, and VCE cultivars indicated a low genetic variability for the onions in this collection. Within this context, the phenotyping and establishment of the genetic distance between these accessions are important for the choice of divergent and mutually supportive parents for developing segregating populations in onion genetic improvement programs in efforts to diversify the national cultivars on the market. Such efforts are required for the IPA breeding program for the introduction of new accessions to increase the onion germplasm variability.