MICROPROPAGATION OF CITRUS BY USING OVULE CULTURE TECHNIQUES

Abstract

Washington navel and Red Khalili orange ovules as well as anthers of Red Khalili orange were subjected to cold pretreatment for different periods and cultured on either Murashige and Skoog, Murashige and Tucker, or modified Murashige and Skoog medium. Different flower sizes, medium strengths, and additives were tested. Also, different 6- benzylaminopurine (BAP) concentrations were evaluated for plantlets regeneration from callus. Meanwhile, irradiation with gamma rays was involved. Moreover, medium states, cytokinin types (kinetin and BAP), and different BAP concentrations were studied in proliferation stage. Beside, different medium strengths, GA3 concentrations, medium states, and auxin types (IBA, NAA) with different concentrations were treated during rooting stage. Furthe1more, DNA fingerprint was involved. It is fomid that, ovules surpassed anthers in Red Khalili orange in all parameters under study. Also, treating of large sized flowers with cold pretreatment for 7 days and culturing then on one-fomth or one-eighth medium supplemented with 200 mg/L of either malt extract or casein hydrolysate induced the best results. Higher doses of gamma irradiation induced on adverse effect while, refers was true with the lower dose. Meanwhile, kinetin with lower level maximized growth parameters while, the lower concentrations (0.5 or 1.0 mg/L) of BAP enhanced proliferation. Moreover, using ofliquid medium with one-fomth or one-eighth medium strength supplemented with 0.5 or 1.0 mg/L of IBA enhanced the highest rooting. However, different GA3 concentrations failed to induce rooting in both Washington riavel and Red Khalili oranges. Furthermore, different bands of DNA fmgerprint showed similar results and differences as a result of gene segregation occmTed from using ovules.