Flow cytometric DNA c-value and ploidy variation in some Iranian apple cultivars

Apple (Malus Miller) belongs to Rosacease family and Pomoideae subfamily. Current apple (Malus × domestica Borkh.) is a complex hybrid of the apple species. Chromosomal basis of this subfamily are x = 17 and the ploidy levels have been reported for diploid (2n = 34), triploid (2n = 51) and tetraploid (2n = 68). Since Iran is close to the apple diversity regoin (Central Asia), it enjoys a good variation in apple varieties. Despite the high variation in apple cultivars and species in Iran, there is not still a database of genome size. Classification of plants according to their genome size, especially at lower taxonomic levels is important for breeders. Over the past years, several methods for estimation of nuclear DNA content (genome size) was common, but recently, the use of flow cytometry (FCM) has been increasingly used. Flow cytometry is the best method to estimate DNA c-value and ploidy levels in apples. In this study, DNA c-Value and ploidy level of Iranian apple varieties has been estimated by flow cytometry and Propidum iodide staining. Also, given the high levels of phenolic compounds in apples, treating with PVP and PVP1% were performed to evaluate the effect of phenolic compounds on genome size. Finally, Histogram analysis and DNA c-value estimation were done with two software, Partec FlowMax and Flowing software. The difference between means was obtained using SAS software ver. 9.2 and LSD tests. The results showed that all studied cultivars were diploid and genome size obtained from Partec FlowMax ranged from 1.73 to 1.57 pg.