ARS | Publication request: Factors affecting adventitious regeneration from in vitro leaf explants of 'Improved French' plum, the most important dried plum cultivar in the USA

Submitted to: Annals of Applied Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 20, 2009
Publication Date: February 7, 2010
Repository URL: http://www3.interscience.wiley.com/cgi-bin/fulltext/122654941/HTMLSTART
Citation: Petri, C., Scorza, R. 2010. Factors affecting adventitious regeneration from in vitro leaf explants of 'Improved French' plum, the most important dried plum cultivar in the USA. Annals of Applied Biology. 156:79-89.

Interpretive Summary: 'Improved French' plum is the most important plum variety for the production of dried plums (prunes). California is the world leader in prune production supplying 100% of the U.S. market and 50-60% of the world market. Prune production represents an income of over $250 million to California growers, and this production is based almost entirely on the variety 'Improved French'. Since it is difficult and has not yet been possible to produce new plum varieties with the desired qualities of 'Improved French', we are developing technologies that can be used to genetically enhance 'Improved French' to make it more disease and insect resistant, and to protect this variety from the destructive and invasive disease Plum pox virus (PPV). In order to insert disease resistance genes into this important variety, we must be able to regenerate new plants from pieces of the original tree through a process called cloning. While this is generally very difficult to achieve with most fruit trees, we have accomplished this with 'Improved French'. This work now paves the way for developing 'Improved French' trees that are resistant to PPV and other diseases that plague plum production.

Technical Abstract: An adventitious shoot regeneration protocol from leaves of the most important dried plum cultivar in the U.S., 'Improved French', has been established. Factors affecting regeneration were studied, and relatively high percentages have been obtained. The proliferation medium were shoots, used as the source of explants, were cultivated, and had a strong influence depending which regeneration was used after that. The best results were obtained with 9.0 uM thidiazuron (TDZ). Regeneration rates were not affected by x-naphthaleneacetic acid (NAA) concentration. Leaf explants incubated in constant light or in the dark for one week before transferred to the light showed more organogenetic activity. The utilization of bactoagar as a gelling agent and the addition of the ethylene inhibitor silver thiosulfate (STS) also increased organogenesis in 'Improved French'.