Abstract: The effects of different embryo developmental stages, treatment time of low temperature, 6-BA
and GA₃ levels, sucrose concentration in culture medium and seed coats on immature embryo development and
normal seedling rate were studied with ultra-earlymaturing nectarine variety Super Red Spur. The results indi
cated that the average PF value was only 0.086 when fruits developed up to 56 days. Among the all treat
ments, the treatmentwith low temperature for 80 days and 6% sucrose concentrations in the culture medium
had the highest effects on immature embryo growth and normal seedlings rate. Moreover, different 6-BA and
GA₃ concentrations showed little influence on the immature embryos cultured for 80 days in low temperature;
but 9 mg/L 62BA had some promotion on the immature embryos development for 30 days. The PF value and
the percent of normal seedling of immature embryos with seed coatswere found better compared with the em
bryo without seed coatswhen cultured at low temperature condition.

Key words: Nectarine, Immature embryo culture, PF value, Normal seedling rate