In Mandarin group, the ovule fertility represents the ability of a variety to produce seed in the fruit. This criterion could be used for the distinction between new varieties from irradiation and which are characterized by a great similarity with the parent varieties. The aim of this work is the research of an estimation technique of the ovule fertility in some variety of Clementine and Mandarin via estimating the seed number produced in manual and open pollination conditions. Three experiments were studied: hand pollination with different concentration of pollen, estimating the stigma receptivity by the percentage of pollen germination in vivo and in vitro and estimating the seed number produced by fruit under open pollination conditions. The results obtained showed that the stigma receptivity decreases when we take away from the anthesis stage. The seed number decreases when pollination was carried out six days after anthesis. In terms of pollen concentration, our results revealed an increase of seed number with the increase of pollen concentration. However, the open pollination conditions, allowed an important distinction between the ovule fertility degrees of the varieties tested. Our results demonstrate the importance of the open pollination technique in the determination of ovule fertility in the Mandarin group of citrus fruits, and therefore, a clear distinction between the varieties of this group.
