- Author: Elizabeth J Fichtner
UCCE Tulare County recently joined an international group of scientists focused on leveraging pecan genetics to develop trees adapted for the diverse geographic regions in which the trees are cultivated and for tree resilience in the advent of climate extremes. Tulare County boasts over 1,000 acres of pecan and is home to one of the state's pecan handlers. Walnuts, a historic nut crop of Tulare County, are in the same plant family as pecan (Juglandaceae); consequently, the relatedness of the two crops has facilitated an overlap of specialization in the grower community, with many long-time walnut growers also managing the state's pecan acreage.
In 2022 the team of 26 scientists was awarded an $8 million USDA NIFA Specialty Crop Research Initiative grant entitled ‘Trees for the future: Coordinated development of genetic resources and tools to accelerate breeding of geographic and climate adapted pecan trees.' Led by Dr. Jennifer Randall at New Mexico State University, the grant provides 4 years of research funding to USDA and major land grand institution scientists, as well as researchers at University of Tokyo and the HudsonAlpha Institute for Biotechnology. From California, Karlene Hanf of Mid-Valley Pecan sits on the advisory board, and Elizabeth Fichtner, UCCE Tulare County nut, olive, and prune advisor, serves as a principal investigator.
In some permanent cropping systems, climate conditions such as low winter chill may affect the overlap of the female and male bloom, affecting crop productivity. To mitigate this risk, pistachio growers sometimes plant multiple pollinizer varieties in orchards. In Tulare County pecan growers rely on two varieties, ‘Western' and ‘Wichita,' to satisfy the reproductive needs of the crop. One goal of the USDA NIFA-funded project is to assess the timing and overlap of the male and female bloom of co-planted varieties over years characterized by different climate conditions. Researchers across the United States are utilizing standardized techniques to assess bud break, shoot development, and bloom on many cultivars to provide phenotypic data that can be utilized by geneticists striving to breed climate resilience in pecan. Additionally, researchers are quantifying damage cause by pecan leaf scorch, a disease caused by a bacterial plant pathogen. The disease has been detected in California; however, it does not appear to be as severe in California orchards as in other regions of the United States.
The USDA NIFA-funded program fosters development of UC ANR competency in pecan production, a smaller acreage nut crop in California. California is the nation's largest producer of almond, pistachio, and walnut, but produces approximately 2% of the USA's total pecan crop. As a north American native plant, pecan is well adapted to cultivation in diverse regions of the United States. Its native range includes the forested lands surrounding the Mississippi River, as well as rivers in southeastern Texas and Mexico. Outside of its native range, pecan remains an economic crop in New Mexico, Arizona, the southeastern United States, and California, particularly in Tulare County.