Normally juvenile tissues derived from citrus plants are
used for in vitro culture experiments whereas application of
mature tissues have been limited due to their low regenera-
tion capacity. (Cervera et al. 2008, Tallon et al. 2013). The
present work corroborates these findings and further dem-
onstrates that the optimal hormone concentrations are spe-
cific to explant, as it has been previously reported for juve-
nile explants (Bordon et al. 2000, Costa et al. 2004, Mendes et
al. 2008). Previous reports on plantlet regeneration from
sweet orange mature tissues included a pre-treatment for
optimum regeneration. Cervera et al. (1998) and Rodriguez
et al. (2008) used stem segments developed from grafted
buds (invigorating), while most of the other investigators
used nursery plants for explant preparation (Kobayashi et al.
2003, Marutani-Hert et al. 2012, Tallon et al. 2013).
To our knowledge, this is the first report of a complete
protocol for adventitious shoot regeneration, rooting and
complete plant regeneration from mature tissues of grove-
grown Thomson navel citrus. This regeneration system can
be used to transform mature explants of citrus navel culti-
vars by particle bombardment or Agrobacterium-mediated
transformation methods.