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United States Department of Agriculture

Agricultural Research Service

Research Project: Management of Genetic Resources & Associated Information for Grape, Tree Fruit, Tree Nut, & Other Specialty Crops to Mediterranean Climates

Location: Nat'l Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes

Title: Phenotypic variation among trees in a population of a Pistacia atlantica X P. integerrima cross sold as UCB-1 rootstock for grafting P. vera (pistachio) cultivars

Author
item Jacygrad, Ewelina
item Preece, John
item Michelmore, Richard
item Golino, Deborah

Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: UCB-1 is widely used in California as a pistachio rootstock because of its Verticillium resistance, salt and cold tolerance, and vigor. It can grow in most locations in California. However, significant variation exists in the phenotypic performance of trees grafted to seedling UCB-1 rootstocks. In July 2013, 961 UCB-1 seedlings were planted near Davis, CA to evaluate phenotypic and genotypic variation in this segregating population. This report focuses on growth performance and how the population’s phenotypic dynamics have changed over the first three years in the field. Annually, data were collected on tree height, trunk caliper, canopy height and diameter, and branching characteristics. The growth dynamics of the population changed as the trees aged, with the greatest uniformity during the first year, and increasing variation in the population in later years. First year growth performance is poorly correlated with that of subsequent years, especially for tree height, caliper, and branching. Therefore, selection for vigorous or weak phenotypes early is the life of the trees misses much of the subsequent variation and is less effective than desirable.

Last Modified: 09/20/2017
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