Assessment of Genetic Relationship among Male and Female Fig Genotypes Using Simple Sequence Repeat (SSR) Markers

Sevin Teoman,Ahmet Ipek,Sezai Ercisli,Umran Erturk,Erdogan Barut,Nesrin Aktepe Tangu,Nesrin Aktepe Tangu,Meryem Ipek,Erdem Durgut

doi:10.15835/nbha45110756

Abstract

Fig (Ficus carica L.) is a traditional crop in Turkey and widely cultivated around the Mediterranean areas. The gynodioecious fig species is present in two sexual forms, i.e. the domesticated fig (female tree) and the caprifig (male tree). Caprifigs are crucial for high quality fig production and breeding while, the studies on assessment of genetic relationship among caprifigs is limited. The aim of this study was to determine genetic diversity among 45 caprifigs and 2 female figs collected from four provinces in Marmara and Aegean Sea Regions of Turkey using simple sequence repeat (SSR) markers. In this work, 24 SSR markers were tested, one was monomorphic and the remaining markers amplified 82 alleles. The number of polymorphic alleles per SSR marker ranged from 2 to 7. The observed heterozygosity (Ho) differed from 0.18 to 0.76 and expected heterozygosity (He) ranged between 0.24 and 0.81. The polymorphism information content (PIC) varied from 0.42 to 0.98. A UPGMA analysis based on Dice similarity matrix clustered fig genotypes into two main groups and similarly, STRUCTURE analysis placed fig genotypes into two different gene pools (K=2). Fig genotypes collected from the same region were not clustered together in a group indicating that the fig genotypes did not cluster on the basis of their collection sites. Our results demonstrated that caprifigs and female figs are not genetically distinct and they clustered together in a group. All fig genotypes had distinct SSR marker profiles suggesting that there were no synonyms or homonyms. These results revealed a high genetic variation among fig genotypes and 23 SSR markers were enough to discriminate all fig genotypes analysed in this study demonstrating that SSR marker system is suitable for genetic analysis in figs.

Highlights

Fig (Ficus carica L.) has been cultivated since ancient times in the world (Janick, 2005) and Mediterranean region where Turkey is located is the origin of common figs (Caliskan and Polat, 2008)
Ferrara et al (2016) reported that, the lowest polymorphism information content (PIC) observed was 0.07 for LMFC23 and LMFC27 primers while the highest was 0.91 for Frub422 simple sequence repeat (SSR) marker. These results suggested that the genetic variation within fig genotypes in this study is high
The present study proved that SSR markers are reliable technique for identifying genetic diversity of both caprifig and female fig genotypes

Summary

Introduction

Fig (Ficus carica L.) has been cultivated since ancient times in the world (Janick, 2005) and Mediterranean region where Turkey is located is the origin of common figs (Caliskan and Polat, 2008). Pollination process, called caprification in ficus species, occurs by transferring pollen from caprifigs to female flowers of edible figs by a pollinator wasp, Blastophaga psenes L. Some parthenocarpic female fig genotypes require no pollination, caprification has become a common practice in commercial fig production in order to obtain sufficient fruit yield and high quality fruit set. Pollination is required for many important Turkish female fig cultivars such as ‘Bursa Siyahı’ and ‘Sarılop’ which are well-known in Marmara and Aegean Regions, respectively. The purpose of this study was to investigate genetic relationship between 45 caprifig genotypes and 2 common Turkish female fig cultivars with SSR markers. The best caprifig genotypes as pollinators of important Turkish fig cultivars such as ‘Sarılop’ and ‘Bursa Siyahı’ are needed and in this respect, caprifig collection in Uludag University can serve as germplasm resources. This study is important to assess and characterize the genetic relationship among caprifigs in this collection

Materials and Methods

Findings

Conclusions