Peach Breeding and Transgenics

Peach breeding (Dr. Ksenija Gasic)

The recently established peach breeding program at Clemson University under the leadership of Dr. Ksenija Gasic is focused on development of high fruit quality varieties for fresh consumption with improved disease and abiotic stress resistance using traditional and molecular approaches.  The research is aimed at solving problems that peach growers and stakeholders are facing in the South Eastern US production region.  There are several diseases (such as brown rot and bacterial spot) and environmental stresses (such as drought and late-spring frost) that reduce peach tree yield and life in the southeastern U.S.A., and add to the cost of peach production. The most economically effective method to manage these problems is to grow resistant varieties.  New and improved peach cultivars with disease tolerance/resistance and adapted to SC environment will help SC peach growers in production of high quality peaches for fresh consumption. Release of cultivars with decreasing disease susceptibility or resistance to brown rot or bacterial spot should impact fungicide applications and therefore human health and environmental issues.  In addition, drought tolerance and late blooming characteristics incorporated into new varieties will be extremely beneficial due to tendency of low rainfall and late frosts in spring.
Research objectives:
1. Develop high quality, disease-resistant peach varieties adapted to environmental conditions of the Southeast.
2. Evaluate peach germplasm with available molecular markers linked to the genes of interest to facilitate the breeding program in combining the best traits isolated in different varieties or in other species from the Prunus genus.
3. Find new markers linked to disease resistance genes

Biotechnology approaches for trait modification (Dr. Luo)

Genetic transformation of woody fruit plants is a promising tool for their genetic improvement, since their breeding has limitations imposed in general by their high heterozygosity, long juvenile periods and auto-incompatibility. Moreover, improvement of fruit trees through traditional breeding methods is a long-term effort because of their long generation time. Thus, application of biotechnology in peach tree genetic improvement would certainly accelerate the breeding process, greatly enhancing its potentials for agricultural production. We have been conducting research in establishing a procedure for genetic transformation of peach tree. The long term goal is to use biotechnology approaches to genetically engineer peach tree for enhanced performance such as biotic and abiotic stress resistance, better fruit and nutritional quality and other important traits.

Development of disease-resistant rootstocks (Dr. Schnabel)

An Armillaria resistant rootstock would be the most effective and environmentally sound approach to manage Armillaria root rot (Oak root rot) in South Carolina peach orchards. However, Armillaria tolerant rootstocks with acceptable horticultural features are not presently available for growers. The recent discovery of the anti-fungal gene GAFP in a Chinese orchid, Gastrodia elata Bl. F. flavida S. Chow, which parasitizes A. mellea, offers new possibilities for managing Oak root rot, Phytophthora root rot and maybe root-knot nematode in peach. GAFP has documented activity against Phytophthora disease and nematodes in trangenic tobacco and plum and is now being investigated in field experiments against Armillaria root rot.