2011 Annual Report
1a.Objectives (from AD-416)
Access currently available, newly released, and new parent rootstock materials for their physiological responses and tolerance to soil salinity and/or drought under greenhouse and field conditions. Quantify the effects of salinity and/or drought on scion physiological performance in terms of vine water relations, gas exhange, vine mineral nutrition, fruit yield, and quality under field and lab conditions.
1b.Approach (from AD-416)
The research will be a combination of field studies on cooperating farms, laboratory studies at UC Davis, greenhouse studies and sand tank studies at U.S. Salinity Laboratory.
This Grant Agreement supports Objective 1 of the parent project. This research is underway in greenhouse, lab, experimental field and commercial vineyard settings. UC Davis researchers initiated experiments to screen rootstock material for salt tolerance including a study of five hybrid populations and one population of V. vinifera cv. Colombard for the trait of chloride exclusion. Tissue processing was completed and analyzed and a manuscript prepared for publication. High variability was observed in this study, and the highest variability of all six rootstock populations tested. This provides an adequate degree of confidence that the time necessary for a full population screen will be productive. Similar uncertainty existed as to whether cv Ramsey and cv St. George differed in their ability to exclude chloride, given that both genotypes are considered strong excluders. The gradation of chloride uptake within the hybrids, with either parent at the ends of this distribution, present clear evidence that cv St. George does exclude chloride more effectively than cv Ramsey. This finding strengthens the possibility that further chloride exclusion may be developed using St. George as a genetic resource. An initial screen was completed of southwestern US Vitis species for reduced chloride uptake following our new greenhouse methods. The screening included 113 individual genotypes collected from low elevation and semi-arid locations in southern California, Arizona, Nevada, Utah, New Mexico and Texas. Preliminary results identified several plants from different species that display lower leaf chloride content than either Ramsey or St. George, the typical low-uptake benchmarks, confirming accessions from this group of species have breeding potential. The lead scientist monitors this Agreement with conference calls, annual research meetings and emails.