Certain regions in Mexico have lost up to 40% of their pecan harvests to a condition that causes nuts to germinate prematurely on trees. The disorder, known as vivipary, renders pecans inedible and unsellable. It has started to pop up in pecan orchards in Arizona and Texas, bringing worries to producers in the United States.
New Mexico State University is leading a group of scientists working to develop genetic tools and resources to breed climate-adapted pecan trees that could combat vivipary and other challenges.
The effort is part of a multistate research project headed by Jennifer Randall, a plant molecular biologist and plant pathologist in NMSU’s Department of Entomology, Plant Pathology and Weed Science in the College of Agricultural, Consumer and Environmental Sciences. Randall recently received a continual grant from the National Institute of Food and Agriculture, part of the U.S. Department of Agriculture, to fund the project for the next eight years, starting with $3.9 million for the first two years.
“Pecan has a native region that spans from Oaxaca, Mexico, to Illinois, which is a huge geographical range with many different climates,” Randall said. “Our goal is to have trees that are best-suited for their regional areas and figure out not just what would be great to grow in specific areas today, but 50 years from now under climate change.”
As project director, Randall will coordinate a research team that includes faculty from NMSU, Texas A&M University, the University of Arizona, the University of Georgia, the University of Oklahoma and the University of California’s Agriculture and Natural Resources. The group also includes USDA scientists in Texas, Georgia and Louisiana.
The researchers’ top objective is to leverage pecan genetics to breed pecan trees for climate adaptation, Randall said. The group will work with the Alabama-based HudsonAlpha Institute for Biotechnology to sequence genomes from pecan DNA to analyze climate-cultivar “genetic mismatches” that cause vivipary, maladaptive budbreak timing and dormant-season hardiness.
“We will generate molecular markers that predict suites of adaptive traits to accelerate breeding for both scion- and rootstock-related traits,” she said. “These data will allow the development of vital genetic tools necessary for increasing our understanding of regional adaptation, promoting resource conservation, and selecting improved cultivars/rootstocks for all major pecan regions.”
The researchers will also examine pecan water relations and responses to salinity and drought stress and explore biological interactions, including beneficial microbiome interactions and diseases caused by fungal and bacterial organisms and insect damage.
Randall said the group has set up research plots in New Mexico, Arizona, California, Texas, Oklahoma and other areas to gather data from different climate regions.
“Part of the strength of this grant is that we’re trying to look at pecan trees in a lot of different pecan regions, not just New Mexico,” she said. “We will help our New Mexico growers, but the main goal is to help pecan growers across the United States.”
Randall said it can take up to 30 years for new pecan varieties to become publicly available. Her goal is to speed up the process using marker-assisted selection for breeding.
“What we’re doing is figuring out the genetics that control traits, so we can reduce the amount of work and time,” she said. “We’ll be able to track the genes in the new progeny without having to wait 20 or 30 years.”
At NMSU, Randall will work closely with the project’s co-principal investigators, who include project co-director Richard Heerema, Jay Lillywhite, Joe Song, Barbara Chamberlin and Nicole Pietrasiak, as well as David Dubois, who will serve as a collaborator.
Randall said NMSU’s Department of Innovative Media Research and Extension will develop interactive gaming simulations to present the project’s data and findings in a user-friendly way. The simulations and other outreach materials for growers and potential growers will be available for free at the project’s website, https://pecantoolbox.nmsu.edu.