The influence of season collection of explants on micropropagation of peach rootstock GF-677

The influence of season on the rate of multiplication on in vitro culture of peach rootstock GF- 677 was investigated on Murashige and Skoog (MS) media, supplemented with GA3 0.1 mg/L and IAA 0.1mg/l. Benzyladenine (BAP) at concentrations 1mg/l was used in the multiplication stage and 1mg/l IBA in the stage of rooting. Shoot-tip and nodal segment explants were collected from 5 years old rootstock GF-677 (Prunuspersica x Prunus amygdalus) in February 24th (from dormant shoots that have been sprouted in climatic room),March 22th, April 20th, May 18th and September 15th during the 2009 growing season and have been sterilized bysodium hypochlorite (NaOCl) 10% for 20 min. The data on the effect of the season collection of the explants on number of shoots per explants, the mean shoot length and the percentage of rooted shoots were recorded sixweeks after culture. In vitro performance of explants indicated a positive correlation between shoot proliferation and season collection The highest number of shoots per explants (3,5) was obtained on explants collected in March 22th (3,5), which was on a par with explants collected in February 24th (from shoots that have been sprouted in climatic room). Moreover, the highest shoot length was observed on explants collected on February and March (1,53cm and 1,505cm respectively). The percentage of rooted shoots from explants sampled onFebruary was not markedly greater than those sampled on March. The number of shoots per explants, the shoot length and the percentage of rooted shoots on explants sampled in April, May and September were significantly lower than those sampled in February and March. The amount of chlorophyll a + b of the shoots coming from explants collected in March was markedly greater than those collected in February, April, May and September.