Establishment Of Regeneration System From Peach Cotyledons And Hypocotyls (Prunus Persica (L). Batsch)

Factors affecting shoot regeneration from cotyledon explants in vitro including different genotypes, different stages of development, plant growth regulators and dark culture were investigated in peach in different maturity . And factors affecting shoot regeneration from hypocotyl explants in vitro including different genotypes, basic medium and plant growth regulators were investigated in peach. The shoot regeneration system from cotyledon and hypocotyl explants in vitro were established, which could be the basis for transgenic technology.The main results are as follows:1. The shoot regenerating rates differed greatly from peach cotyledon explants on different stages of development and different genotye. The best time for shoot regeneration from cotyledon explants were 76 days after full bloom for early-maturing peach cultivars including'Yanhong11','Zhongyong 4'and'Shuangxihong', and the corresponding highest shoot regenerating rate was 31.25%,75% and 64.58%. The best time for shoot regeneration from cotyledon explants were between 80 and 84 days after full bloom for mid-maturing peach cultivars including'Shahong','Xiangshanhu'and'Ruiguang 28', and the corresponding highest shoot regenerating rate is 50%,43.75% and 20.83%. The best time for shoot regeneration from cotyledon explants were between 80 and 84 days after full bloom for late-maturing peach cultivars including'Tiantaowang','Shenzhouhongmi'and'Zhongyou 8', and the corresponding highest shoot regenerating rate was 47.92%,43.753% and 54.17%. When PF was about 0.6, the shoot regeneraing rate was the highest of'Shenzhouhongmi'. When PF was 0.7～0.8, shoot regeneraing rate was the highest of the other cultivars. Cotyledons of different cultivars showed different shoot regenerating rate.'Zhongyou 4','Shuangxihong'were cultivars with high shoot regeneration from cotyledon explants.'Yanhong11'and'Ruiguang 28'were cultivars with low shoot regeneration from cotyledon explants.2. Plant growth regulators showed important effect on shoot regeneration from coytledon explants. The suitable plant growth regulators for shoot regeneration were 2.0 mg/ L TDZ with 0.01～0.04 mg/ L NAA or 0.1 mg/ L IBA. The highest shoot regenerating rate of'Shuangxihong'cotyledons was 64.58% in MS medium with 2.0 mg/ L TDZ and 0.04 mg/ L NAA. The highest shoot regenerating rate of'Shahong'cotyledons was 56.25% in MS medium with 2.0 mg/ L TDZ and 0.1 mg/L IBA. The highest shoot regenerating rate of'Shenzhouhongmi'cotyledons was 45.83% in MS medium with 2.0 mg/ L TDZ and 0.01 mg/ L NAA. For high shoot regeneration the optimum time of cotyledons in dark culture was 10 days. The proximal region of embryonic axis had the high regeneration ability and the other part of cotyledons with cut had very low regeneraiton ability.3. Shoot regenerating rate from hypocotyl explant showed significant difference in different genotye. In the same culture condition,'97-8-4'hypocotyls showed the highest regeneration and the regeneraing rate is 90.74%.'Tiantaowang'hypocotyls and'Jintong 5'hypocotyls showed the relatively high regeneration and the corresponding regenerating rate is 75.49% and 72.60%.'Shenzhouhongmi'hypocotyls,'Qinmi'hypocotyls and'Huaguang'hypocotyls showed low regeneration, and the corresponding regenerating rate was 64.45%,36.94% and 31.11%.4. The basic medium and plant growth regulators showed great effect on shoot regeneration from hypocotyl explants. QL was the optimum basic medium for shoot regeneration of'97-8-4'hypocotyl explants and'Tiantaowang'hypocotyls explants. MS was the optimum basic medium for'Jintong 5'hypocotyl explants. The optimum plant gorwth regulators were 2.0 mg/ L BA or the combination with 0.04 mg/L NAA.'97-8-4','Tiantaowang'and'Jintong 5'showed the highest regenerating rate on QL+2.0 mg/ L BA +0.04 mg/L NAA + 100 mg/ L inositol, QL +2.0 mg/ L BA +0.04 mg/ L NAA + 100 mg/ L inositol +500 mg/ L CH, MS +2.0 mg/ L BA +0.04 mg/ L NAA + 200 mg/ L inositol respectively and the corresponding highest regenerating rate was 94.44%, 80.42%, 78.00%. 5. The shoot multiplication coefficient of'Tiantaowang','Jintong 5'and'97-8-4'was 4～5 in QL medium with 1.0 mg/ L BA and 0.04 mg/ L NAA. The rooting rate of'Tiantaowang','Jintong 5'and'97-8-4'was more than 70% in 1/2 QL medium with1.0 mg/ L NAA.