RESEARCH OF CITRUS TRIPLOID HYBRIDS BY EMBRYO RESCUE AND FLOW CYTOMETRY FROM TWO ORANGES VARIETIES Pineapple AND Parson Brown

Triploids are the most important materials for the selection of citrus seedless cultivars. Moreover, flow cytometry has been used for plant DNA content estimation; likewise, it was succeeded in the use for testing ploidy levels and hereditary origin of the triploid plants. The current study’s purpose was to produce triploid hybrid from underdeveloped seeds cultivated in different media of two oranges cultivars: Pineapple and Parson Brown. For that, all abnormal seeds collected from mature fruits were sterilized and cultured on Murashige and Tucker base medium supplemented with different concentrations of composition. Then, the ploidy levels of seedlings from the rescue of immature embryos were evaluated by flow cytometry. Germination rate is the highest in M3 (MT+ 25 mg/l Adenine sulfate) with 100% and 90% for both Pineapple and Parson Brown varieties, respectively. In addition, the germination time is shorter in M1 (MT + 1 mg/l gebberellic acid) for both varieties, which takes six and seven days. The triploidy rate varied according to the seed shape. It was found in small seeds with 66%, followed by 40% in flat seeds for Parson Brown variety. While 25% were recovered from flat seeds in Pineapple cultivar. Therefore, M1 remains the best to promote high rate of germination. Flow cytometry analysis could be used for obtaining accurate and rapid results for cytological observations of seedling populations of Citrus.