Location: Crop Germplasm Research
Project Number: 6202-21000-029-00-D
Project Type: In-House Appropriated
Start Date: Mar 1, 2008
End Date: Feb 19, 2013
The long-term goal of this project is to produce improved scion and rootstock cultivars for the U.S. pecan industry. The project will also elucidate genetic control of important pecan traits using traditional and molecular genetics techniques. Over the next 5 years we will focus on the following objectives: Objective 1: Enlist phenotypic breeding techniques, supplemented with molecular tools, to develop and release new pecan scion cultivars with high yield and quality, and improved disease and insect resistance. Sub-objective 1.A: Develop high yielding pecan scion cultivars with early nut maturity, improved nut quality, and superior disease and insect resistance. Sub-objective 1.B: Develop DNA markers to identify genetic variability and enhance the selection of superior scion cultivars. Objective 2: Enlist traditional selection techniques and newly developed molecular tools, to develop superior pecan rootstocks with outstanding vigor and salt tolerance. Sub-objective 2.A: Establish patterns of variation in pecan seedlings as a function of geographic origin. Sub-objective 2.B: Develop additional molecular genetic tools for use in pecan, including markers based on sequences of the chloroplast genome and capable of discriminating between accessions of pecan on the basis of maternal inheritance. Objective 3: Apply qualitative and quantitative techniques, in conjunction with molecular techniques, to elucidate the genetic control of key horticultural traits (such as yield level, nut size, time of nut maturity, salt tolerance, and disease and insect resistance) for pecans. Sub-objective 3.A: Elucidate the genetic control of key horticultural traits in pecan utilizing appropriate qualitative and quantitative techniques. Sub-objective 3.B: Establish families of controlled cross seedling pecans suitable for use in mapping qualitative and quantitative trait loci related to scab disease resistance, and to determine levels of scab resistance within those progenies.
Research objectives will be met by basic genetic research and by an intensive cultivar and rootstock selection program. These improvements will be accomplished through several approaches. Phenotypic breeding techniques, supplemented with molecular tools, will be used to develop and release new pecan scion cultivars with high yield and quality, and exhibiting improved disease and insect resistance. Similar approaches will be utilized to develop superior pecan rootstocks with outstanding vigor and salt tolerance. Qualitative and quantitative techniques, in conjunction with molecular techniques, will be used to elucidate the genetic control of key horticultural traits in pecans. Genetic research conducted by this project will increase our knowledge of the genetic control of yield components, nut maturity, nut quality, tree size, and disease and insect resistance. The scion cultivar development component of the work will produce precocious, high-yielding, regular bearing, disease- and insect-resistant cultivars that also have high nut quality. Rootstock breeding activities will produce new rootstocks with improved vigor, uniformity, salt tolerance, disease and insect resistance, and specific geographical adaptation; and which will ultimately contribute to increased yields of grafted scions.