|Beckman, Thomas - Tom|
|Chaparro, Jose - University Of Florida|
Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/6/2014
Publication Date: 5/20/2015
Citation: Beckman, T.G., Chaparro, J.X. 2015. Peach rootstock development for the Southeastern United States. Acta Horticulturae. 1084:171-178.
Interpretive Summary: In the early 1990’s premature tree mortality in the southeastern U.S. peach production area was a significant threat to the economic viability of this fresh market peach industry. Average tree life in the main production areas of central Georgia and South Carolina was economically unsustainable, averaging only 7 and 9 years, respectively. The primary causes of mortality were peach tree short life (PTSL) and Armillaria root rot (ARR). Guardian rootstock, cooperatively released in 1993 by the USDA and Clemson University, significantly reduced tree losses to PTSL but itself was highly susceptible to ARR and one of the root-knot nematode species that are endemic to this production area. The Byron rootstock development program has made considerable progress in the identification of sources of resistance to PTSL, ARR and the several species of root-knot nematodes that are distributed widely in this production area. To date two rootstocks with resistance to this entire disease complex have been cooperatively released by the USDA and UFL. ‘Sharpe’, a clonal hybrid plum rootstock, was released in 2007 and ‘MP-29’, a clonal plum x peach interspecific hybrid rootstock, was released in 2011. As an added plus, both rootstocks provide a marked reduction in scion vigor. Several more disease resistant rootstock releases are anticipated that will broaden the range in vigor control provided which will give growers a valuable new tool to fine-tune their trees to their management style and site constraints.
Technical Abstract: The primary focus of the stone fruit rootstock program at Byron, Georgia has been the development of disease resistant rootstocks for peach. Historically peach tree short life (PTSL), aka ‘Bacterial Canker Complex’, and Armillaria root rot (ARR) have been the two most important causes of premature mortality of commercial peach trees in the southeastern United States. However, following the cooperative release of Guardian rootstock by the USDA-Agricultural Research Service and Clemson University in 1993 the southeastern peach industry has enjoyed a marked decline in incidence of PTSL. Unfortunately, Guardian, like most other peach seedling rootstocks, is very susceptible to ARR. As a result, ARR has now moved to the forefront as the primary cause of premature peach tree death in the Southeast. Since its inception in 1988, the Byron rootstock program has focused on the breeding and development of new peach, plum and plum x peach interspecific hybrid rootstocks with resistance to PTSL, ARR and several species of root-knot nematode including Meloidogyne incognita, M. javanica and M. floridensis. M. floridensis is a recently identified nematode species with demonstrated ability to attack many of the current commercial peach rootstocks with resistance to M. incognita, including Okinawa, Nemared, Nemaguard and Guardian. Our breeding and evaluation work has recently culminated in the release of two clonal rootstocks with broad disease and nematode resistance. ‘Sharpe’, a semi-dwarf, clonal, plum hybrid, was released in 2007 for commercial testing and as a germplasm line. ‘MP-29’, a semi-dwarf, clonal, plum x peach hybrid, was released in 2011 for commercial testing. ‘MP-29’s broad disease and nematode resistance in combination with its dwarfing ability and excellent productivity offers great promise for use in this production area and others worldwide suffering from similar maladies.