Using of Somatic Embryogenesis for Improving Bolting-resistant New Local Cultivars of Heirloom Carrot Cultivars (Daucus carota) Under Egyptian Conditions

Abstract

Foreign carrot varieties with desirable morphological traits for the local and global markets must bloom in low temperatures for a long period of time in Egypt, but these climatic conditions are not available for flowering and seed production for these varieties, so it is common to import carrot seeds from abroad. On the other hand, Local cultivars bloom earlier when planted later than the advised date. Due to the heat, it cannot be grown throughout the summer. Pushing the somatic cells to divide and create a new polarity is necessary for the induction of tissues in the lab and the creation of somatic embryos. It was shown that several auxins play a crucial role in the development of these embryos, particularly 2, 4-D (2,4-dichlorophenoxyacetic acid). This experiment was carried out to investigate the effect of five procedures in a tissue culture laboratory using two concentrations of 2, 4-D at a concentration of 2.5 and 5 mg/l for indirect somatic embryos induction from sexual embryos produced from culturing carrot  (Daucus carota) seeds of Carrot cv. Kuroda (an heirloom variety). The results confirmed by scanning electron microscopy showed that it is crucial to compare the various processes used to create somatic Embryogenesis to assess their effectiveness. The four stages of somatic embryos, globular, heart, torpedo, and cotyledon form, were observed on the formed callus. The highest amounts of callus fresh weight, the number of globular-shaped stage embryos, the number of heart-shaped stage embryos, the number of torpedo-shaped stage embryos, the number of cotyledon-shaped stage embryos, and the number of seedlings had been recorded in the media supplemented with 2, 4-D at a concentration of 5 mg. This study was able to produce somatic embryos of the foreign carrot cv. Kuroda, Plants obtained from somatic embryos are included in selection programs to produce varieties resistant to early flowering under Egyptian conditions. These results constitute a step in the way in the field of improving bolting-resistant new local cultivars of heirloom carrot cultivars (Daucus  carota) under Egyptian conditions.