Regeneration of Peach [Prunus persica (L.) Batsch] Rootstock Cultivars from Cotyledons of Mature Stored Seed

Abstract

Shoots were regenerated from cotyledons of mature stored seed of three peach rootstock cultivars (`Flordaguard', `Nemared', and `Medaguard'). Shoot regeneration rates were highest when cotyledons were cultured for 3 weeks in darkness on Murashige and Skoog (MS) medium with 2.5% sucrose and a combination of IBA (1.25 or 2.5 μm) and TDZ (6.25 or 12.5 μm). Regeneration rates for `Flordaguard', `Nemared', and `Nemaguard' were as high as 60%, 33%, and 6%, respectively. Length of seed storage (1 to 3 years) did not affect regeneration rates. Seventy percent of regenerated shoots produced rooted plants. This regeneration method is rapid and simple, and stored seed can be used year-round. It may be a useful regeneration system for gene transfer in seed-propagated peach rootstocks. Chemical names used: 5 indole-3-butyric acid (IBA); thidiazuron (TDZ).