In vitro Propagation of Citrus Species through Callus Induction and Regeneration: A Review (original) (raw)

International Journal of Current Microbiology and Applied Sciences

Citrus, one of the most important group of fruit crops around the world, are propagated at large scale with many difficulties. Propagation through seeds is challenging because of Phytophthora foot rot together with recalcitrance of citrus seeds. Vegetative propagation of Citrus species is mainly performed now-a-days by budding on seedling rootstocks. As heavy losses are experienced among the susceptible seedlings due to Phytophthora and Citrus tristeza virus (CTV), the interest in resistant rootstocks has greatly increased. The potential of conventional methods of citrus plant breeding of rootstocks are limited by physiological factors such as heterozygosity, inbreeding depression, nucellar polyembryony and juvenility. Under such conditions advanced tissue culture techniques provide best possible alternative for producing large number of resistant progenies from elite citrus genotypes. Plant tissue culture provides reliable and economical method of maintaining pathogen free plants that allows rapid multiplication and international exchange of germplasm. Generally, when in vitro propagation protocols are developed for any specific plant species, specialized conditions for individual genotypes, elite species and even various developmental stages of the explants plants are selected via error-andtrial experiments. Because large diversity is observed in Citrus plant family, it takes many months to develop protocols for most suitable culture medium, best concentrations and combinations of plant growth regulators and other supplements for better development of explant cultures. Therefore, in this review, we tried to put together results from difficultto-find literatures and listed all the identified findings, in which callus induction or somatic organogenesis was used to develop citrus plants. Successful protocols of surface sterilization method, culture establishment, shoot regeneration, in vitro rooting and acclimatization are presented systematically.