Callogenesis and plant regeneration of sweet orange cv. Washington Navel from floral organ cultures

Abstract

Washington Navel orange (Citrus sinensis L.) can be infected with virus and virus like diseases that affect not only the production but also fruit quality and the plant’s longevity. For viral sanitation, Washington Navel regeneration was investigated in vitro via floral organ culture. Flowers were collected before opening from healthy Washington Navel trees kept under greenhouse. Floral organs (style/stigma and ovary) were cultured on Murashige and Skoog (MS) medium containing various plant growth regulators combinations of naphthalene acetic acid (NAA), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The highest rate of callogenesis (95%) was obtained from style/stigma explant cultures on MS medium enriched with 3 mgL-1 BAP, which also resulted in 100% rooted plantlets. Ovary cultures did not show any success on the culture medium with various plant growth regulators combinations. The acclimatization success of rooted plantlets by grafting on Citrus volkameriana rootstocks was about 83%. Thus, these results can be used for mass production of disease-free citrus plants and improve sanitation program of the local citrus genotypes in Tunisia.