Abstract:
There is a necessity for genetic improvement of local Citrus species to meet the national
requirement and to exploit the potential export market. Delayed flowering is a main barrier for
Citrus genetic improvement and seedling derived crop cultivation. Therefore, we attempted to
improve two local Citrus species for early flowering through transformation by Agrobacterium
bearing 35S:Flowering Locus T (FT), and 35S: VJmybA2 for enhancement of ornamental value
by induction of purple pigmentation. We followed the seedling transformation as an efficient
alternative method. Purple pigmentation was clear on putative VlmybA2 seedlings of Nasnaran
(Citrus madurensis) after 2 weeks of transformation, but they could not survive. Only one axillary
shoot was observed in a putative chimeric 35S.FT seedling out of seedlings after 4 weeks of
transformation. Above plant could not survive during acclimatization. Significantly lowest plant
height was observed in putative VlmybA2 Jamanaran (Citrus nobilis)) plants. Purple pigmentation
was not evident in them. Auxin production may be altered in 35S: VlmybA2 plants resulting in
lowest plant height. Inter nodal length, number of nodes and number of leaves were significantly
reduced in putative 35S.FTplants by 3 months of transformation. Fifty five percent of putative
35S: FT plants produced axillary shoots while there were no axillary buds in control or 35S:
VlmybA2 plants after 4 months of transformation. Early axillary buds and reduced intermodal
lengths in putative 35S.FT could be signs of early flowering in Citrus. FT being a mobile signal
for flowering induction, there is a possibility that the protein produced at base of the plant due to
transformation could move upward for axillary bud initiation. Our results indicate that there is a
potential in 35S.FT to alter the plant growth and structure. This experiment is being continued
through morphological and molecular analysis to determine the effect of FT on early flowering.
