NMSU professor leads climate pecan study

NMSU Professor Jennifer Randall is seen here on November 18, 2022 in a lab with clonal pecan trees. (Darren Phillips/NMSU)

Copyright © 2022 Albuquerque Journal

What about pecans?

In parts of Mexico, 40% of pecan crops have been lost to viviparity, a condition that causes the nuts to germinate prematurely.

“Before the pecan falls off a tree, it begins to sprout to form a whole new tree,” said Jennifer Randall of New Mexico State University. “A little root comes out of the pecans. You can’t eat them. You can’t sell them. It’s going to be quite a problem.”

She said the condition had begun to emerge in the United States, affecting pecan orchards in Texas and Arizona. This is one of several challenges facing pecan production associated with climate change.

Randall is a Ph.D. Plant Molecular Biologist and Plant Pathologist in the Department of Entomology, Plant Pathology and Weed Science at NMSU. She is also the lead researcher in a group of scientists working to develop genetic tools to breed climate-adapted pecan trees.

“As the climate changes, it’s important to get the genetic information that breeders need to have the right trees to grow in specific areas today, but also 50 years from now,” Randall said. “Vivipary is simply part of it. We look at water quality, drought stress, salinity tolerance (salt content). We look at gene networks that determine flowering, pecan composition and tree architecture, smaller trees because growers would like to grow more trees per hectare.

“We study diseases caused by fungal and bacterial organisms as well as insects. Damage from moisture, things we don’t see (in New Mexico). We will help our growers in New Mexico, but the main goal is to help pecan growers in the United States.”

A lot to do

Works like this are not new to Randall.

“We had a grant (from the US Department of Agriculture) that started in 2016 and ended just this year,” she said. “We reported the genomes (genetic material) of four pecan varieties — Pawnee, Lakota, Elliot, and Oaxaca.”

There are hundreds of pecan varieties, of which the Wichita, Western, and Pawnee are the most common in New Mexico. Randall said the pecan has a home range that stretches from Oaxaca in Mexico to Illinois, an area with many different climates.

The new multi-state research project, led by Randall, is funded by a four-year grant from the National Institute of Food and Agriculture, part of the USDA. An award of US$3.9 million will be paid for the first two years.

Randall leads a team composed of faculty from NMSU, Texas A&M, University of Arizona, University of Georgia, University of Oklahoma and University of California. This includes USDA scientists in Texas, Georgia and Louisiana.

“We have so many people working on it because we’re busy,” Randall said.

The group will work with the Alabama-based HudsonAlpha Institute for Biotechnology to analyze genetic mismatches that result in vibrancy, buds that are unable to adapt to environmental changes and other issues.

Randall said the data collected will enable the development of vital genetic tools needed to understand regional adaptation and select improved crops and rootstocks for all major pecan regions.

Research is carried out both on the ground and in laboratories. There are research properties in Arizona, California, Texas, Oklahoma, New Mexico and other areas.

“Much of the work will take place in the Mesilla Valley (in New Mexico),” Randall said. “We have pecan orchards on our Leyendecker Experimental Farm here in Las Cruces. Among the things we will be looking at there are rootstocks that are salt tolerant due to the precarious soil and water restrictions here.”

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New Mexico is a major player in pecan production.

This September 2021 photo taken in the orchards at NMSU’s Leyendecker Plant Sciences Research Center shows a cluster of pecans in the early shuck-split stage. (Courtesy of Richard Heerema)

According to 2021 USDA figures, the latest available, the state has 46,000 acres of pecans, which ranks it fourth behind Georgia, Texas and Oklahoma. This does not apply to acres planted with immature trees that are not yet producing pecans.

The 2021 USDA report also showed that New Mexico produced more than 78 million pounds of inshell pecans, second only to Georgia, for a value of nearly $189 million, ranking first in the country.

Statistics like these are critical to Richard Heerema, a pecan specialist at NMSU and a member of Randall’s research team.

“We have people with expertise in economics, ecology, soil science, molecular biology and more,” Heerema said of the researchers. “My own area of ​​expertise is horticulture and plant physiology.”

Living in New Mexico, it’s no surprise that Heerema focuses on how pecan plants fare in dry conditions.

“I’m interested in salt tolerance because the accumulation of salt in the irrigation water or in the soil can cause physiological stress in the (pecan) plant,” he said. “I’m very interested in tolerance to water stress (lack of moisture), how the root works and how the leaf works. I am interested in the connection between the genetics of the plant and how it tolerates water stress.”

He wants to know how this works with existing strains, but he’s also intrigued by the possibility of improving strains.

“In a four-year fellowship, we won’t have time to develop new varieties,” Heerema said. “But we may be able to identify genetic markers that could later be used to develop new varieties.

“We will get an idea of ​​how these plants tick.”