Analysis of the genetic diversity of Azerbaijani fig accessions (Ficus carica L.) using pomological traits and inter simple sequence repeat (ISSR) markers

Abstract

The genetic diversity of fig (Ficus carica L.) germplasm in Azerbaijan was assessed using pomological traits and inter-simple sequence repeat (ISSR) markers. All 90 accessions exhibited significant variation in fruit-related traits. The studied fig accessions displayed a full spectrum of fruit skin ground colors, from yellow to black, with yellow–green (32.2%) and yellow (26.6%) being the most prevalent colors. The majority of the fruits were categorized as globose (73%). Fruit weight among the fig accessions varied from 18.8 g (‘Nikitskiy 4067’) to 83 g (‘Konservniy’), with an average of 44 g. Azerbaijani figs demonstrated similar weight ranges, with 13 local accessions exceeding 50 g, including ‘Iri Absheron’, ‘Agh Enjir’, and ‘Vuqarli’. Two-way cluster analysis based on these traits identified fruit weight and dimensions as the primary grouping factors. Preliminary ISSR analysis using eight primers revealed polymorphism levels ranging from 40 to 100%, with an average of 63.5%. The mean genetic diversity among the 90 fig genotypes was calculated to be 0.65. Local Azerbaijani accessions exhibited comparable diversity to those from Ukraine and lower diversity than those from the United States. The Jaccard genetic distance index among the accessions was low. Both Azerbaijani and introduced accessions in the neighbor-joining (NJ) tree showed a random distribution that was independent of origin, which was further confirmed by principal coordinate analysis (PCoA). These results provide a valuable baseline for future breeding programs and can aid in the identification and conservation of these genetic resources.