Progress 10/01/09 to 09/30/10
Outputs Progress Report Objectives (from AD-416) To develop through gene transfer, pear trees and pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. Approach (from AD-416) Pear cultivars will be transformed with genes that have the potential to cause dwarf plant growth either as rootstocks or scions. Candidate dwarfing genes will be tested under the control of various gene promoters that may lead to differences in the expression of dwarfing. Certain promoter-gene combinations will be investigated for their potential as rootstocks to dwarf and induce precocious fruit bearing. A GA2 oxidase gene was used to transform pear with the goal of dwarfing its growth. One selected transformed pear plant was verified as having the gene. To determine if GA2 oxidase was the proper gene to use to dwarf pears, a more efficient and faster system using plum was used to test the effects of the GA2 oxidase gene. Several GA2 oxidase transgenic plum clones are currently under test for dwarf growth and dwarfing ability as rootstocks. If these plums cause dwarfing, additional efforts to introduce this gene into pear will be undertaken. The ADODR has monitored activities through emails, meetings, and calls.
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Progress 01/01/05 to 12/31/09
Outputs Progress Report Objectives (from AD-416) To develop through gene transfer, pear trees and pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. Approach (from AD-416) Pear cultivars will be transformed with genes that have the potential to cause dwarf plant growth either as rootstocks or scions. Candidate dwarfing genes will be tested under the control of various gene promoters that may lead to differences in the expression of dwarfing. Certain promoter-gene combinations will be investigated for their potential as rootstocks to dwarf and induce precocious fruit bearing. A GA2 oxidase gene was used to transform pear with the goal of dwarfing its growth. One selected transformed pear plant was verified as having the gene. To determine if GA2 oxidase was the proper gene to use to dwarf pears, a more efficient and faster system using plum was used to test the effects of the GA2 oxidase gene. Six GA2 oxidase transgenic plum clones have been developed. They are all short internode dwarfs. They respond to GA application by producing new growth with longer internodes. After a period of post-GA-application elongation growth, plants revert back to short internode growth. Standard plum clones will be grafted to these GE plants to evaluate their effect as rootstocks on scion growth. The ADODR has monitored activities through emails, meetings, and calls.
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Progress 10/01/08 to 09/30/09
Outputs Progress Report Objectives (from AD-416) To develop through gene transfer, pear trees and pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. Approach (from AD-416) Pear cultivars will be transformed with genes that have the potential to cause dwarf plant growth either as rootstocks or scions. Candidate dwarfing genes will be tested under the control of various gene promoters that may lead to differences in the expression of dwarfing. Certain promoter-gene combinations will be investigated for their potential as rootstocks to dwarf and induce precocious fruit bearing. Significant Activities that Support Special Target Populations A GA2 oxidase gene was used to transform pear with the goal of dwarfing its growth. Only one selected transformed pear plant was verified as having the introduced GA2 oxidase gene. To determine if GA2 oxidase was the proper gene to use to dwarf pears, a more efficient and faster system was used to test the effects of the GA2 oxidase gene for dwarfing trees. Several GA2 oxidase transgenic plum clones are currently under test for dwarf growth and dwarfing ability as rootstocks. If these plums cause dwarfing when used as rootstocks, additional efforts to introduce this gene into pear will be undertaken. The ADODR has monitored activities through emails, meetings, and calls.
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Progress 10/01/07 to 09/30/08
Outputs Progress Report Objectives (from AD-416) To develop through gene transfer, pear trees and pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. Approach (from AD-416) Pear cultivars will be transformed with genes that have the potential to cause dwarf plant growth either as rootstocks or scions. Candidate dwarfing genes will be tested under the control of various gene promoters that may lead to differences in the expression of dwarfing. Certain promoter-gene combinations will be investigated for their potential as rootstocks to dwarf and induce precocious fruit bearing. Significant Activities that Support Special Target Populations A GA2 oxidase gene was used to transform pear with the goal of dwarfing its growth. One selected transformed pear plant was verified as having the introduced GA2 oxidase gene. The transformation protocol now needs to be modified to recover transformed pear plants at a greater frequency. The ADODR has monitored activities through emails, meetings, and calls. This research addresses NP 301 (Plant Genetic Resources, Genomics, and Genetics Improvement ) Component 3. Genetic Improvement of Crops, Problem Statement 3C: Germplasm Enhancement/Release of Improved Genetic Resources and Varieties.
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Progress 10/01/06 to 09/30/07
Outputs Progress Report Objectives (from AD-416) To develop through gene transfer, pear trees and pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. Approach (from AD-416) Pear cultivars will be transformed with genes that have the potential to cause dwarf plant growth either as rootstocks or scions. Candidate dwarfing genes will be tested under the control of various gene promoters that may lead to differences in the expression of dwarfing. Certain promoter-gene combinations will be investigated for their potential as rootstocks to dwarf and induce precocious fruit bearing. Significant Activities that Support Special Target Populations This report serves to document research conducted under a non-funded cooperative agreement between ARS and Walt Disney World Company/WORLDCO (EPCOT). Additional details of this research can be found in the report for the parent project 1931-21000-011-00D, Genetic Improvement of Fruit Crops. Pear trees are notably slow to produce fruit. Bearing trees are large and do not lend themselves to newer, more efficient orchard operations. The objective of the project is to develop, through gene transfer, pear scions and/or rootstocks that produce precocious, productive, dwarf trees with high quality fruit. The transformation experiments utilized a gene which degrades a plant hormone involved in shoot elongation. In order to improve efficiency of the gene transfer method, factors affecting efficiency of transformation, plant regeneration, and selection of transformed plantlets were investigated. Modification of the testing method resulted in gene transfer. Additional modifications are being evaluated. Positive transformation with a fluorescence marker gene, which will help identify the stages of the process which are limiting successful transformation and selection, have also been achieved. Methods used to monitor activities included periodic communication by email and telephone, conference calls, and a site visit to the laboratory at EPCOT.
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Progress 10/01/05 to 09/30/06
Outputs Progress Report 4d Progress report. This report serves to document research conducted under a non-funded cooperative agreement between ARS and Walt Disney World Company/WORLDCO (EPCOT). Additional details of this research can be found in the report for the parent project, 1931-21000-011-00D, Genetic Improvement of Fruit Crops. Pear trees are notably slow to produce fruit. Bearing trees are large and do not lend themselves to newer more efficient orchard operations. The objective of the project is to develop, through gene transfer, pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. In order to improve pear regeneration efficiency, which is necessary for high rates of transformation, factors affecting efficiency of regeneration were investigated. Higher concentrations of the synthetic plant hormone, thidiazuron, were found to improve regeneration of new plantlets. Differences among pear cultivars in regeneration capacity were
determined, and cultivars with high levels of regeneration were identified.
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Progress 10/01/04 to 09/30/05
Outputs 4d Progress report. This report serves to document research conducted under a non-funded cooperative agreement between ARS and Walt Disney World Company/WORLDCO (EPCOT). Additional details of this research can be found in the report for the parent project, 1931-21000-011-00D, Genetic Improvement of Fruit Crops. The objective of the project is to develop, through gene transfer, pear rootstocks that produce precocious, productive, dwarf trees with high quality fruit. In order to improve pear regeneration efficiency, which is necessary for high rates of transformation, factors affecting efficiency of regeneration were investigated. Higher concentrations of the synthetic plant hormone, thidiazuron, were found to improve regeneration of new plantlets. Differences among pear cultivars in regeneration capacity were determined, and cultivars with high levels of regeneration were identified.
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