Abstract:

The main composition of culture media such as the basic medium and hormones were tested for their effects on Peach ( Prunus persica ) callus frequency from immature embryos (which picked after full flower 45 days and 55 days respectively) under (26±1)℃ without light in an orthogonal experiment. And a method for plant regeneration from immature cotyledons (55 d) has been developed by cultured on MS media supplemented with 2% sucrose and 0.75% agar and hormone in various combinations. The results showed that: The basal medium was the most important factor for inducing callus from embryos. MS was adapted to ‘Yulu’ (45 d and 55 d) and ‘Hujingmilu’ (55 d). NAA 1.0 mg·L ^-1 and 0.5 mg·L ^-1 were better for ‘Yulu’ (45 d and 55 d,respectively), BA 0.5 mg·L ^-1 was better for ‘Hujingmilu’ (55 d), but 2,4-D hadn't any important effect on callus inducing from the examined material. Days after fecundation was another factor effect on callus induction. The highest callus frequency from 45 d immature embryos was 96.6% and it was 81.6% from 55 d embryos. Shoots regeneration occurred when callus was transferred to a medium in which the NAA concentration was 0.05 mg·L^-1 and BA was 1.0 mg·L^-1. Shoot regenerated roots in the medium of 1/2 MS+1.0 mg·L ^-1 IBA. 2 types of hormone combinations (NAA 0.50 mg·L^-1+BA 10.0 mg·L^-1, NAA 0.05 mg·L^-1+TDZ 3.0 mg·L^-1) were favorable to shoots differentiation for the immature cotyledons. The regeneration was changed when cotyledons were wounded horizontally by a razor blade. The best results were obtained when cotyledons with embryonic axis and wounded in the surface. Adventitious shoot could regenerate on the 1/2MS medium with IBA 1.0 mg·L^-1 and Ad 20 mg·L^-1.

Key words: Peach (Prunus persica), immature embryos, cotyledons, callus, regeneration