Investigating Peach Varieties using Plant Biotechnology and Best Management Practices

Peach (Prunus persica) is one of the most important stone fruits in the southeastern states and has great economic and nutritional value. However due to Peach Tree Short Life (PTSL), yield is affected (Werner and Okie 1998). PTSL is a syndrome that is caused by interaction of abiotic and biotic factors that reasons damage to the above ground portion of the tree. To improve and develop better quality peach varieties we need to utilize best management practices, breeding and plant biotechnology techniques. Plant biotechnology techniques utilizing tissues from woody fruit trees have had little success due to its recalcitrant nature. Therefore, a reproducible protocol in peach could greatly expedite the plant development and is desirable. Contamination in woody tree tissue culture like peach is very difficult to eradicate, which has been reported in many woody plant species. The primary aim of this study was to develop a surface sterilization method to control contamination in peach cultures, which is prerequisite for in vitro study. This investigation was carried out to investigate the efficiency of plant growth regulators and different media on explant establishment. There are many factors that affect the in vitro growth of field grown explants like the cultivar, explant types, medium and growth regulators.  Various explants were collected from newly established High Density Peach Orchard at the FVSU-ARS. Nodal segments were surface sterilized with constant agitation in 8.25% fungicide, then agitated in 0.5% Mercuric chloride for 20 min followed by three rinses with distilled waster. Leaf tissues were surface sterilized either with 0.25 % (w/v) mercuric chloride for 2.5, 5, 10 min, or with 10 % sodium hypochlorite for 2.5, 5, 10 min. Explants were inoculated on various media. The best medium for bud break in peach was BAP, Ad.S. and Kinetin on Woody Plant Medium (WPM). Embryo rescue is an important aspect of in vitro plant biotechnology. Immature (1-6 week old) peach fruits were collected and surface sterilized in 75% ethanol for 30 minutes. Embryos were isolated from peach fruit manually. The embryos were placed on embryo culture media with high sucrose contain medium. Responses observed from this study include callus, root formation and somatic embryo formation. Embryo cultures survived more than 1 year after induction.