A Hot Spot of Olive Biodiversity in the Tunisian Oasis of Degache

Olfa Saddoud Deddabi,Fathi Ben Amar,Valentina Fanelli,Cinzia Montemurro,Susanna Gadaleta,Mona Siblini,Ali Chehade,Saliha Boucheffa,Sihem Ben Maachia,Monica Marilena Miazzi,Milad El Riachy

doi:10.3390/d12090358

Abstract

Tunisia is one of the world’s largest producers of olive oil, and it preserves pools of olive genetic diversity that are still unexplored. A recent prospection and collection program of the National Gene Bank of Tunisia (NGBT) focused on the vast oasis of Degache, in the south west part of Tunisia, where 47 samples were collected and genetically characterized through simple sequence repeat (SSR) markers. Identification and authentication of genotypes were obtained through comparison with reference cultivars belonging to the Olive National Collection of Tunisia (IOC) and with cultivars from Algeria, Italia, Syria and Lebanon. Degache olive genotypes showed large genetic variability, a significant diversity from the reference germplasm, and a clear differentiation from modern varieties. The population structure analysis identified four gene pools characterizing genotypes from different area of origin. Two gene pools appear to be more represented in germplasm from southern Tunisia, where environmental conditions at critical plant development phases, are harsher. This suggests that this germplasm might present traits of adaptation useful for breeding to improve resilience to abiotic stresses. Our results will support ex situ and in situ conservation activities of Tunisian olive germplasm pursued by the National Gene Bank of Tunisia.

Highlights

Olive growing is progressively increasing in Tunisia, with an actual cultivated surface of about1.8 million ha, which corresponds to 30 percent of the North African cultivated land [1]
Only one genotype was retained, 37 samples were further used for subsequent analyses (Table S1)
PIC values revealed in the 37 olive Degache accessions analyzed with 10 simple sequence repeat (SSR) markers

Summary

Introduction

Olive growing is progressively increasing in Tunisia, with an actual cultivated surface of about1.8 million ha, which corresponds to 30 percent of the North African cultivated land [1]. Olive growing is progressively increasing in Tunisia, with an actual cultivated surface of about. Varietal introductions from all over the Mediterranean basin, France, Spain, Morocco, Greece, have further enriched the Tunisian olive germplasm. Genetic resources are the bases of crop adaptation They allow crops to respond to environmental challenges such as those produced by the ongoing climate changes, helping to sustain the production in marginal lands, and enhancing food security and quality [8,9,10].

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Conclusion