Title : Molecular assessment of genetic diversity of some Tunisian fig (Ficus carica L.) accessions using RAPD, ISSR and SSR Markers
Fig (Ficus carica L.) is one of the most important fruit species grown in Mediterranean regions. In Tunisia, the production is about 29 000 tons, it represents 3 % of total word production. The fig is an economically important fruit species, which is cultivated extensively in over the country. RAPD and ISSR markers were used to determine the genetic diversity and relatedness among 12 fig accessions and SSR markers were studied on 30 fig accessions preserved at the ex situ plant collection established in El Gordhab (Tataouine) in the South-eastern of Tunisia. Although, we tested 3 primers for RAPD, 4 primers for ISSR and 13 for SSR. Concerning the RAPD technique, a total of 31 DNA loci were detected in which 29 loci (93.61 %) were polymorphic. DNA fragments presented a minimum of 8 and a maximum of 11 polymorphic bands using primers OPL11 and OPW04, respectively. Primers exhibited collective resolving power values (Rp) of 13. Regarding the ISSR markers, 47 DNA loci were detected in which 41 loci (87.24 %) were polymorphic. DNA fragments of polymorphic bands varied from 8 (AM5) to 14 (AM6). Primers revealed collective resolving power values (Rp) of 14.8. The ‘Bither3’ and ‘Bither4’ accessions showed the highest genetic distances for RAPD and ISSR markers, respectively. Dendrogram constructed by UPGMA based on RAPD and ISSR banding patterns were independent. The SSR markers showed that 40 alleles were revealed. The number of alleles ranged between 2 to 6 with a mean of 3.08 alleles per locus. The observed heterozygosity (Ho) ranged from 0.03 (LMFC21, LMFC23, and LMFC32) to 0.83 (LMFC30) with an average of 0.43. The expected heterozygosity (He) varied from 0.03 (LMFC21, LMFC 23 and LMFC32) to 0.74 (LMFC30) with an average of 0.37. UPMGA cluster analysis and PCA grouped the accessions in 6 groups. The RAPD, ISSR and SSR markers indicated that there is a great genetic diversity among Tunisian fig accessions, making them a valuable genetic source for incorporation into potential breeding programs for fig selection.