Olive is one of the oldest cultivated species in the Mediterranean Basin, including Tunisia, where it has a wide diversity, with more than 200 cultivars, of both wild and feral forms. Many minor cultivars are still present in marginal areas of Tunisia, where they are maintained by farmers in small local groves, but they are poorly characterized and evaluated. In order to recover this neglected germplasm, surveys were conducted in different areas, and 31 genotypes were collected, molecularly characterized with 12 nuclear microsatellite (simple sequence repeat (SSR)) markers, and compared with 26 reference cultivars present in the Tunisian National Olive collection. The analysis revealed an overall high genetic diversity of this olive’s germplasm, but also discovered the presence of synonymies and homonymies among the commercialized varieties. The structure analysis showed the presence of different gene pools in the analyzed germplasm. In particular, the marginal germplasm from Ras Jbal and Azmour is characterized by gene pools not present in commercial (Nurseries) varieties, pointing out the very narrow genetic base of the commercialized olive material in Tunisia, and the need to broaden it to avoid the risk of genetic erosion of this species in this country.
Citrus genus includes a wide number of species that have been long cultivated and well adapted in Tunisia. It is represented by small number of plantations and considered as underutilized in Tunisia. Our goal was to genetically characterize Tunisian lime genotypes to obtain data useful for gene conservation and breeding purposes. The survey of genotypes was conducted in the Cap Bon region, where citrus cultivation is the most spread. Sixteen quantitative and 19 qualitative parameters were evaluated. The observed accessions belonged to three different species: Citrus limetta, Citrus latifolia (limes Byrsa), and Citrus limettioides (limes of Palestine) according to Tanaka classification. Principal component analysis confirmed these classifications. Four-cell analysis (FCA) was used to determine the most threatened genotypes. Quantitative traits were evaluated and allowed the discrimination between genotypes. Many quantitative traits of fruit and juice were highly positively and significantly correlated. Phenotypic diversity was determined using Shannon–Wiener diversity index (H’). The highest value of diversity index was observed for both vesicle thickness and thickness of segment walls (H’ = 0.98). Intermediate values were observed for both fruit axis (H’= 0.49) and pulp firmness (H’ = 0.43). However, fruit shape (H’ = 0.24), shape of fruit apex (H’ = 0.24), and vesicle length (H’ = 0.33) presented the lowest values of diversity index. Current findings will be useful to conserve threatened genotypes ex situ and on farm and also will guide strategic conservation on Citrus genetic resources for future breeding programs.
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