GENETIC RESISTANCE TO PIERCE'S DISEASE ON GRAPES

Goals / Objectives
To develop Pierce's disease resistant table and raisin grapes by crossing currently available forms of resistance with large berried and seedless V. vinifera table and raisin grapes.

Project Methods
Crosses will be made between grape germplasm with Pierce's disease resistance and the most advanced table and raisin cultivars and selections. Seedlings will be screened for resistance in the greenhouse. Duplicated plants of the resistant seedlings will be fruited and evaluated in the field for fruit quality. Successive generations will be made and tested as quickly as possible to accumulate the necessary fruit quality traits with disease resistance so the ultimate goal of resistant commercial cultivars can be reached. Documents Trust with UC-Davis. Log 19407. Formerly 5302-21220-003-10R (10/03).

Progress 04/01/01 to 03/31/05

Outputs
4d Progress report. This report serves to document joint research conducted under a reimbursable agreements with University of California, Davis for research on Pierce's Disease. Additional details of research can be found in the report for the parent project 5302-21220-004-00D Improvement of Prunus and Vitis Scion and Rootstocks for Fruit Quality and Pest Resistance. Pierce's Disease (PD) resistant grapes are needed to provide a long term solution to outbreaks of PD due to the disease and introduction of new vectors. Over 320 F1 and BC1 plants from crosses with Southeastern United States (SEUS) Pierce's disease resistant selections were planted in the field. An additional 550 F1 plants from crosses with a resistant V. arizonica selection were planted in the field. Finally 62 BC1 and 214 BC2 plants from crosses with 89-0908 [Vitis rupestris x (V. arizonica x V. champinii)] resistant germplasm were planted in the field. Crosses were made for table, raisin and wine grapes. F1 and BC1 plants from the 89- 0908 resistant source were evaluated for resistance in the greenhouse and tested for molecular markers. Flanking SSR markers showed good correlation with the greenhouse tests. Twenty F1 and 21 BC1 plants have been selected for resistance to Pierces disease. The molecular markers developed are useful for selecting resistant germplasm.

Impacts
(N/A)

Publications

Progress 10/01/03 to 09/30/04

Outputs
4. What were the most significant accomplishments this past year? 4D. Progress Report. This report serves to document joint research conducted under a trust agreement between ARS and California Table Grape Commission (5302-21220- 004-02T), California Raisin Marketing Board (5302-21220-004-03T), and reimbursable agreements with University of California, Davis (5302-21220- 004-05R, 5302-21220-004-08R and 5302-21220-004-11R) for research on Pierce's Disease. Additional details of research can be found in the report for the parent project 5302-21220-004-00D Improvement of Prunus and Vitis Scion and Rootstocks for Fruit Quality and Pest Resistance. Pierce's Disease (PD) resistant grapes are needed to provide a long term solution to outbreaks of PD due to the disease and introduction of new vectors. This year 27 seedless x seedless crosses were made and 3,527 ovules were cultured to develop plants. Twelve of the crosses produced 850 ovules and were made to develop the 1st BC2 populations from the Vitus rupestris x (V. arizonica x V. champinii) resistant source. Eight crosses and 1,348 ovules were made to produce BC1 populations with SEUS resistant germplasm. Another cross included a BC1 from V. rotundifolia resistant germplasm. Crosses were made for table, raisin and wine. Of the 126 selections tested for PD resistance in the greenhouse, 37 were resistant. Populations screened in the greenhouse ranged from no resistance to 50% resistant offspring. This shows some genotypes are better parents than others.

Impacts
(N/A)

Publications