BREEDING PIERCES DISEASE RESISTANT WINEGRAPES

• Author(s): Tenscher, Alan; Walker, Andrew;
• Abstract: We continue to make strong progress breeding Pierces disease (PD) resistant winegrapes. We have incorporated marker-assisted selection (MAS) for the PD resistance gene, PdR1 (see companion report), into our breeding and reduced the seed to seed breeding cycle to three years, allowing very rapid progress towards PD resistant winegrapes. This years crosses were focused on broadening the V. vinifera winegrape base in our breeding lines. We produced thousands of seed with 87.5% and 75% vinifera progeny. Many of our current populations have the PdR1 allele from F8909-08; we made many crosses this year to include the alternate PdR1 allele from F8909-17. Crosses were also made to produce a new mapping population for a collaborative project with the USDA-Parlier to allow mapping of PD resistance from the resistant Florida selection BD5-117, which will help with comparative evaluations of PD resistance genes. The best sources of PD resistance allow very low levels of Xylella fastidiosa (Xf) to develop in xylem vessels. If these were grafted onto phylloxera resistant rootstocks, the Xf in them might kill the rootstocks. Thus, we have made crosses to produce PD and nematode resistant rootstock, and can use MAS for both PdR1 and the Xiphinema index resistance gene, XiR1. We made crosses to develop a number of additional mapping populations for fine-scale mapping efforts with PdR1. We also replicated advanced 87.5% Syrah and Chardonnay selections with PdR1 to produce enough fruit for wine evaluation studies next fall. Finally, we are studying wine making and quality parameters at the 1L, 20L and 2,000L levels to determine which quality parameters are predictive at all scales and which will be best suited to large scale winemaking tests on single vine selections.
• Publication Date: Nov 2006
• Journal: 2006 Pierce's Disease Research Symposium