Rescue of Peach Embryo in Culture Media with Additional of 6-benzylademine and Gibberellic Acid

Abstract

Culture media and plant growth regulators (PGRs) are important factors for successful embryo rescue. Four medium formulas: Brooks and Hough (BH), Woody Plant (WP), Gilmore, and Monet, were compared for their effects on rescuing immature embryo of peach and later development into seedlings. The results indicated that all media allowed embryos to continue their development and generated high percent germination ( >80%). Seedlings germinated in WP and BH were significantly larger in size than those in either Monet or Gilmore. Survival rate of transplanted seedlings was highest in WP (54.4%). Overall observation pointed to WP as the best culture medium in rescuing immature peach embryos. In the following experiment, the response of immature embryos to PGRs: BA and GA3, in WP was evaluated for germination and seedlings formation. Most embryos germinated well (>85%) with or without PGRs; however, resulting seedlings showed much difference. Numbers of seedling with dead shoot tips were much lower when either or both PGRs were added in the medium. The results showed that WP with 0.1 mg/l GA3 and either 0.5 or 1.0 mg/l BA yielded 100% germination and no rosetting seedlings. Significant linear responses (P = 0.04) of seedling height and quadratic responses (P = 0.03) of seedling dry weight were observed with GA3. Seedlings showed significant linear response (P < 0.01) with BA for their leaf number, but total leaf area remained comparable. Positive correlations between seedling dry weight with root length (r = 0.23), root number (r = 0.49), leaf number (r = 0.24) and leaf area (r = 0.3) were significant, while that between dry weight and seedling height was not significant.