EFFICIENT PLANT REGENERATION CULTURE FROM LEAF EXPLANTS OF IN VITRO-GROWN SWEET CHERRY

Four cultivated cultivars, Prunus avium ‘Benisyuhou’, ‘Benitemari’, ‘Benisayaka’, and ‘Satonishiki’ were used in these experiments.
Beni-series have been bred at the Yamagata Horticultural Experiment Station.
The shoots of these cultivars were subcultured in the modified MS basal medium which contained 1 mM phloroglucinol (PG) supplemented with 0.5 mg/L 6-benzylaminopurine (BA) and 0.1 mg/L indolebutyric acid (IBA). The expanded and furled leaves were collected from the shoots.
Each leaf was cut several times just across the midrib, and put in Woody Plant (WP) liquid medium supplemented with 5 mg/L 2,4-D for 1 day.
After soaking, the leaves were placed on the regeneration medium, the WP agar medium supplemented with 5 mg/L thidiazuron (TDZ). The regeneration rate (no. of leaves that formed adventitious shoots/cultured leaves) and number of adventitious shoots were scored after culturing for 3 months.
The furled leaf explants had a higher shoot regeneration rate (77.3±5.1%) than the expanded leaves (26.2±5.6%) in ‘Benisyuhou’. Also the number of adventitious shoots increased in the furled leaf explants from 0.6/leaf to 2.7/leaf.
The younger leaf explants indicated a higher regeneration response than the old leaves.
In addition, the pre-culture treatment including 2,4-D is effective for inducing the adventitious shoots from the leaf explants.
Comparing the regeneration ability among the four cultivars using the furled leaf explants, ‘Benisyuhou’ and ‘Benitemari’ had the higher regeneration rates (about 80%) than ‘Satonishiki’ and ‘Benisayaka’ (20–30%). These adventitious shoots are able to easily grow in acclimated plants.