Interspecific somatic hybrid of Ichang papeda with Valencia orange

Protoplasts from the leaf of Ichang papeda (Citrus ichangensis Swingle) were fused with the protoplasts of embryogenic suspension culture of Valencia orange (Citrus sinensis Osbeck) in vitro by polyethylene glycol (PEG)-induced fusion. The regenerated embryoids were malformed and were transferred onto shoot induction medium. The shoots were then grafted on 15-day-old seedlings of trifoliate orange in vitro. Chromosome counts of the young leaves showed that the parents were diploids, 2n = 2x = 18, and the regenerated plants were tetraploids, 2n = 4x = 36. Peroxidase and glutamate oxaloacetate transaminase isozyme analysis confirmed that these tetraploids were somatic hybrids. They have the bands of both parents. The hybrid plants grew vigorously after transplanted into soil. Leaf morphology of the hybrid was similar to that of sweet orange.