Variability of morphological charters among Tunisian apricot germplasm
Résumé
Morphological characters were assessed for 112 Tunisian apricot accessions using 42 qualitative and quantitative traits according to the UPOV descriptor. The results showed a distinction among all the accessions, and each morphological variable tested was polymorphic except mucron and rootstock. This characterization revealed that Tunisian apricot germplasm complied with many of the listed UPOV descriptor modalities, with the exception of a rectangular-plate fruit shape, which is characteristic of six Tunisian cultivars and not included in the UPOV apricot testing guidelines. The morphological characters with the best discriminatory ability included fruit size, fruit shape, over color of the fruit skin and flesh, and leaf size. The variability structure highlighted two different apricot categories: (i) Bargougs characterized by very small fruit size with high FW/FLW and absence of over color, (ii) grafted cultivars characterized by medium to relatively large fruit and the presence of over color. Morphological variability was structured according to the geographical origin of the plant material. Four regions were clearly distinguished: north, center, south and oasis. The assessed Tunisian apricot germplasm presented great variability, similar to that of Turkish, Spanish and Italian apricots.