An In Vitro Germination Technique for Some Stone Fruit Species: the Embryo Isolated from Cotyledons Successfully Germinated without Cold Pre-treatment of Seeds

Seeds of temperate fruit species need a long time to germinate as a result of their requirement of stratification or cold treatment. Therefore, fast and uniform germination techniques are desirable and important for fruit tree propagation and especially for breeding studies. The effects of combinations of benzylaminopurine (BAP) and gibberellic acid (GA(3)) on in vitro embryo germination of apricot, peach, and wild cherry were determined without seed cold pretreatment. The results showed that no germination was recorded in all the seeds with testa. In the seeds without testa, no germination (wild cherry) or limited germination (less than 10%) was recorded. When the embryos separated from cotyledons were cultured, successful germination was obtained for all species. In general, the addition of different combinations of BAP and GA(3) into the Murashige and Skoog (MS) medium significantly increased the germination ratios of embryos without cotyledons in all species. For wild cherry, the best treatment (66.7% germination) was MS media containing 0.5 mg.L-1 BAP + 2.0 mg.L-1 GA(3) or 0.5 mg.L-1 BAP + 4.0 mg.L-1 GA(3). For peach, the best treatment (86.7% germination) was MS medium supplemented with 0.5 mg.L-1 BAP + 3.0 mg.L-1 GA(3). For apricot, the best treatment (93.3%) was MS media containing 0.5 mg.L-1 BAP + 3.0 mg.L-1 GA(3), 1.0 mg.L-1 BAP + 1.0 mg.L-1 GA(3), or 1.0 mg.L-1 BAP + 2.0 mg.L-1 GA(3).