ANALYSIS OF PLOIDY LEVEL SEEDLINGS DERIVED FROM in vivo GERMINATION OF IMMATURE EMBRYOS OF ORANGES

The triploid is a promising process in the creation of new seedless strains. Pineapple oranges and Parson Brown are characterized by the high quality that provides lots of seeds. However, our interest is a potential of two types as a female parent and as a seedless fruits hybrid production. Our study focuses on anomalous in vivo germination of these two varieties in order to obtain seedless triploid fruit varieties while analyzing their level of ploidy by flow cytometry. In fact, seeds are extracted from ripe fruits and are classified according to their morphological flat seeds, the small and the normal ones. Then, they were sown in greenhouse and in pans containing 50 % of peat and sand. The statistical analyses have shown that there is a significant difference between the form of seeds and the two varieties for all the outcomes studied. The germination rate has ranged from “20%” to “90%” depending on the normal shape and the abnormal one. Likewise, after seven weeks, stem growth has fluctuated from “4,90” to “7,40” with a comparatively low value in terms of smaller grain of the two varieties. With regard to the average germination time, it was significant for the shape of the seed and non-significant between the two varieties whose time is the highest to the small shape. Likewise, flow cytometric analysis of somatic embryogenesis allows to their level of ploidy to be determined. In fact, the rate of triploidy varies from “0%” to “9,5%” for Parson Brown and Pineapple varieties respectively. While the rate of haploidy was “2,5% for the flat shape of Parson Brown. This way of in vivo germination of immature oranges embryos may complement the in – vitro technique of rescue by mastering well the favorable conditions of germination.