Studies On Tissue Culture And Genetic Transformation Of Peach

Peach (Primus persica (L.) Batsch) is one of the world most important fruit and a famous crop of Zhejiang Province of China. Excellent quality, attractive color, good taste and marvelous fragrance make it a popular fruit in the market. Peach is a climacteric fruit and ripened in summer season which is associated with high temperature and humidity and all these factors make it difficult to store for longer periods. Storage under low temperature causes chilling injuries and makes it exposed to degradation. Much work has been done to control this problem by manipulating the storage conditions, but couldn't solve this problem.To keep pace with the global market, a year-round supply of produce is required. Fruit varieties need to be evaluated for appropriate post harvest characteristics that allow longer periods of storage without losing quality or experiencing internal breakdown. New methods are to be explored to control the ripening process. In peach there are genes such as stony hard and slow ripening that control ethylene production and maturation similar as in found in tomato. The fruit maturation and post harvest physiology studied in the model plants as tomato should be followed to identify new genes in peach that control ripening. To achieve this objective we extensively studied trait for the further studied.This research study describes peach tissue culture and gene transformation technique in detail. Plants were regenerated from the immature embryos and cotyledons of Peach cv. 'Yulu' and 'Hujingmilu'. Immature cotyledons were infected with particle bombardment and Agrobacterium tumefaciens, which carries ACC oxidase antisense gene. Kanamycin-resistant (KanR) shoots were regenerated from the cotyledons. The results of PCR, PCR-southern and genomes southern hybridization analysis showed that the peach ACC oxidase antisenes gene was integrated into peach genomes. The results were summarized below.1. The main composition of culture media such as the basic medium and hormones were tested for their effects on peach callus frequency from immature embryos (which picked after full flower 45 days and 55 days respectively) under 26?'C without light in an orthogonal experiment. The result showed that: 1) 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). 2) NAA 1.0 mg/L and 0.5 mg/L were better for Yulu (45 d and 55 d), BA 0.5 mg/L was better for Hujingmilu (55 d), but 2,4-D hadn't any important effect on callus inducing from the examined material. 3) Days after fecundation is another factor effect on callus induction. The highest callus frequency from 45d immature embryos was 96.6% and it was 81.6% from 55d embryos. Shoots regeneration occurred when callus was transferred to a medium in which the NAA concentration was 0.05 mg/L and BA was 1.0 mg/L. Shoot regenerated roots in the medium of 1/2 MS +1.0 mg/L IB A.2. A method for plant regeneration from immature cotyledons of peach has been developed. The immature cotyledons (45 d and 55 d) of peach were cultured on MS media supplemented with 2% sucrose and 0.75% agar and hormone in various combinations. Cultures were incubated at (26 + 1)℃ with 16h/8h light/dark cycles of approximately 2000-3000 Lux. The result showed that 2 types of hormone combinations (NAA 0.50 mg/L + BA 10.0 mg/L, NAA 0.05 mg/L + TDZ 3.0 mg/L) were favorable to shoots differentiation. The regeneration ability of 'Yulu' peach was higher than that of 'Hujingmilu', and the regeneration frequencies of 55-days immature cotyledons ('Yulu') were slightly higher than that of 45-days. 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. Shoots could regenerate from every part of cotyledons, such as the abaxial side and adaxial side. Adventitious shoot could regenerate on the 1/2MS medium with IBA 1.0 mg/L and Ad 20 mg/L.3. Using transient expressio...