Options growing for Nevada’s fruit and vegetable crops

University researchers investigating new varieties that grow well in desert climates

butternut squash

This spring, Maninder Walia, assistant professor and Extension field crop specialist, began a three-year butternut squash crop trial based on consumer demand.

Options growing for Nevada’s fruit and vegetable crops

University researchers investigating new varieties that grow well in desert climates

This spring, Maninder Walia, assistant professor and Extension field crop specialist, began a three-year butternut squash crop trial based on consumer demand.

butternut squash

This spring, Maninder Walia, assistant professor and Extension field crop specialist, began a three-year butternut squash crop trial based on consumer demand.

June is National Fresh Fruit and Vegetable Month, and researchers at the University are hard at work finding fruit and vegetable varieties best for growing in Nevada.

In the College of Agriculture, Biotechnology & Natural Resources, and its Experiment Station and Extension units, researchers are actively studying fruit and vegetable varieties requested by consumers and small-scale agricultural producers. Their goal is to help producers improve yield to meet demand while diversifying which produce can be grown commercially in the harsh climates of both the Great Basin and the Mojave Desert.

“I think now, maybe more than ever, people are beginning to realize the importance of having a safe, secure food supply, grown locally, to nourish our residents,” said Bill Payne, dean of the College. “When we help our agricultural producers discover new crops and techniques, we not only help provide a local food supply, but we also help sustain our agriculture and restaurant industries, boosting our state’s economy.”

Squashing out high demand

Many of the fruit and vegetables being studied by the College were chosen because they’re what Nevada consumers want. This spring, Maninder Walia, assistant professor and Extension field crop specialist, began a three-year specialty crop trial in Fallon, Nevada, based on consumer demand. Her focus is on butternut squash.

“There is a high demand from casinos in particular for butternut squash,” Walia said. “They use it for soup and other recipes.”

There were four varieties of butternut squash planted in Fallon at Lattin Farms. Rick Lattin, with Lattin Farms, and Bob Dexter, with Dexter Farms, helped plant the crops and will help maintain and measure the squash as it grows. They will also help market the varieties for consumers to sample. Kelli Kelly, executive director of the Fallon Food Hub and a chef, will help taste-test and market the squash varieties, as well as help collect consumer feedback about the varieties’ quality and flavor.

The squash will be compared to already existing varieties in terms of quality, consumer demand, ability to grow in Nevada’s climate and overall yield. Results of the comparisons will be shared with local growers and community members through fact sheets, on-farm demonstration trials and community events and activities. The project will also include an education component where school students will be introduced to sustainable agriculture and the benefits of eating healthy, nutritious and sustainable food.

Prickly (pear) eaters

In the southern part of the state, John Cushman, professor of biochemistry and molecular biology, and Carol Bishop, Extension educator for Northeast Clark County, recently concluded a five-year study that focused on using spineless prickly pear cactus for human consumption, livestock feed and biofuel.

“Both fruit and vegetable production are equally important for this species,” Cushman said. “The cactus’ fruit is important for jams and jellies due to its high sugar content, and the cactus’ pads are eaten both fresh and as a canned vegetable, in addition to its use as a forage or fodder.”

Results of the study, which took place at the Experiment Station’s Southern Nevada Field Lab in Logandale, Nevada, showed that Opuntia ficus-indica had the highest fruit production while using up to 80% less water than some traditional crops. In addition, because the pads are made of 90% water, the cactus provides great potential for food for sheep and cattle production in drought conditions.

Last year, Cushman began a new research project with prickly pear at the U.S. Department of Agriculture – Agricultural Research Service’ National Arid Land Plant Genetic Resources Unit in Parlier, California. In addition to continuing to take measurements of how much the cactus crop will produce, Cushman’s team, in collaboration with Claire Heinitz, curator at the unit, is looking at which growing conditions provide the greatest production and how to prevent certain diseases and pests.

One of the goals of the project is to learn more about Opuntia stunting disease, which causes cactuses to grow smaller pads and fruit. The team is taking samples from the infected plants to look at the DNA and RNA to try to find what causes the disease and learn how the disease is transferred to other cactuses in the field. The hope is to use the information to create a treatment to prevent the disease’s spread and to salvage usable parts from diseased plants.

The team is also investigating different pesticides to find one that is safe for both human consumption and for bees that pollinate the cactuses. More information on the project can be found on the prickly pear project’s website

A pomegranate parade

Since the conclusion of the first prickly pear project, the least successful performing variety at the Southern Nevada Field Lab was replaced with 19 varieties of pomegranates provided by Youping Sun, an assistant professor in landscape horticulture at Utah State University. This summer, the trees will be maintained by University of Nevada, Reno undergraduate student Cole Bennett, who will also be measuring their growth.

“Logandale already grows a lot of pomegranates and even has a big Pomegranate Festival each year,” Bishop said. “However, these are 19 varieties that, to our knowledge, have never been grown in southern Nevada before with the potential to expand the long-term economics of the area.” 

Hopping around

In Las Vegas, many local breweries want to use locally grown hops. In response, Extension’s M.L. Robinson, associate professor and horticulture specialist, is conducting research on the best hops varieties for the region at the Center for Urban Water Conservation in North Las Vegas, a partnership of Extension and the University of Nevada, Las Vegas.

The Hops Project is in its seventh year and is testing eight varieties, including varieties used for making teas. Thus far, the neomexicana hops from the southwestern U.S. have shown the best results.

Previous hops research included Extension’s Professor Emeritus Jay Davison testing four varieties at Workman Farms in Fallon in 2012, and his work with Urban Roots in Reno in 2014 testing 10 varieties at the Experiment Station’s Main Station Field Lab, as part of the Experiment Station’s Desert Farming Initiative.

The Hops Project is in its seventh year and is testing eight varieties, including varieties used for making teas. Photo by College of Agriculture, Biotechnology & Natural Resources.

The center of flavor

Other projects in Las Vegas are split between the Center for Urban Water Conservation and the Outdoor Education Center at the Extension office in Clark County – Las Vegas. Between them, Robinson, fellow Associate Professor and Extension Horticulture Specialist Angela O’Callaghan, and Extension’s Master Gardener volunteers are studying more desert-adapted fruits and vegetables.

The Center for Urban Water Conservation is home to a demonstration orchard, where a variety of fruit trees are being tested to see which ones provide the best yields. Trees include peaches, apples, apricots, Asian pears, European pears, persimmons, figs, nectarines, pomegranates and true date palms.

One of the newer additions to the orchard are jujube trees, also known as Chinese date trees, which are not normally found in the Mojave Desert region. These trees produce small- to medium-sized red fruit that can be dried, eaten fresh and used to make tea.

At the Outdoor Education Center, Robinson and O’Callaghan’s team is conducting several projects related to growing vegetables in southern Nevada. One of the main projects is the investigation of perennial vegetables, such as artichokes and asparagus. Due to the region’s high temperatures and extremely dry and salty soil, standard commercial varieties don’t always work; however, they’ve found that lesser-grown varieties can be produced with some help.

“Yes, you can grow in southern Nevada, and it works. But it’s different than most other places.” – Angela O’Callaghan

The team is also comparing the results of growing vegetables in raised beds versus growing them in amended soil, or soil with added nutrients. Results for the highest yield appear to be heavily dependent on the individual vegetables. In some cases, even different varieties of the same vegetable respond differently to growing location – one variety may grow better in a raised bed, while another grows better in amended soil. The team is investigating what causes those differences, and they’re compiling their results in an easy-to-understand publication for both backyard and commercial growers.

“We have several years of data and are trying to figure out how to best convey those results to the public,” O’Callaghan said.

Additional southern Nevada projects include garlic variety trials, temperature trials, compost trials, attempts to increase growing seasons and ways to protect plants from pests.

Wine state

Much of the College’s research is shared between northern and southern Nevada, as their goal is to find crops that work in both the Great Basin and the Mojave Desert regions. Last year, Robinson and Biochemistry Professor Grant Cramer concluded a study in southern Nevada on hybrid grape varieties. The hybrids were grown as part of the Table and Wine Grape Project, which began as a partnership with Andy Walker, a grapevine breeder with University of California, Davis. Together, the team tested several varieties, including some discovered by Walker, as grape rootstock that grows well in dry, salty soil. The study concluded with positive results, showing that many wine grape varieties work well in southern Nevada. Many of the varieties grew exceptionally well without needing fertilizer, and some have been provided to local winemakers.

“We discovered that the grapes receiving less water produce the better crop, as ‘suffering’ grapes produce more sugar,” Robinson said. “Southern Nevada is a good location for growing grapes, as due to the lack of rainfall, we can control more easily the amount of water they get, which means we can fine-tune it to produce a better-quality wine.”

Also last year, the team, along with Assistant Professor of Sustainable Horticulture Felipe Barrios-Masias, received a new grant to expand their grape research. The team partnered with Oregon State University to investigate a stress hormone called abscisic acid and its role in drought- and salt-tolerant grapes. With funding from the Experiment Station and the U.S. Department of Agriculture, Cramer, Robinson, Masias and their team are testing and comparing two rootstocks recommended by Walker: Riparia, from the northeastern U.S. where the climate is wet, and Ramsey, from Texas.

The team grafted cabernet sauvignon vines onto each of the rootstocks and will be comparing the two combinations to each other and to a cabernet sauvignon growing on its own roots. The Ramsey rootstock has been observed to have a higher salt- and drought-tolerance than the other two. In the Barrios Lab, graduate student Maria Sole Bonarota is researching why the Ramsey rootstock seems to do better under drought conditions and how the root anatomy of the different rootstocks affect water uptake and help regulate water loss through the leaves.

In the Cramer Lab, graduate student Haley Toups is studying the production of the stress hormone, particularly in the Ramsey rootstock, as it appears to produce more of the hormone than the other two rootstocks. She’s specifically investigating how the stress hormone impacts the plants’ drought tolerance and ability to regulate water.

In addition, graduate student John Baggett is investigating the salt tolerance of the rootstocks. Specifically, he’s looking at concentrations of chloride in the leaves of the grapes, and how the chloride impacts salt tolerance. The team had noticed that the chloride concentrations were lower in the Ramsey rootstock, and Baggett is investigating to see if it has something to do with root absorption.

Graduate student John Baggett uses a special tool to measure the photosynthesis of one of the grapevines. Photo by Grant Cramer.

In Oregon State, Associate Professor of Horticulture Laurent Deluc is helping to measure the stress hormone. He’s also working with conducting genetic modifications to better understand the hormone production process.

“The overall goal of all the research attached to this grant is, if we can better understand the production of the stress hormone and its impact on the rootstocks and vines, we can modify the vines to produce better yields with less water,” Cramer said. “That’s perfect for both northern and southern Nevada.”

Seeing red

Another project that recently concluded in southern Nevada was a study on how to increase the growing season for tomatoes by using shade. O’Callaghan found that a 30% shade cover can improve tomato production by protecting plants and fruit from the Mojave’s intense summer sunlight and heat. She published one journal article and is working on a publication to benefit the community.

In northern Nevada, Barrios-Masias recently concluded research into how different tomato rootstocks may help improve tomato crop yields despite northern Nevada’s cold soils in early spring and hot summers. Through the course of the study, the Barrios Lab compared a standard tomato variety with plants grafted onto four different rootstocks, which were then grown at Holley Family Farms in Dayton and Lattin Farms in Fallon under the lead of graduate student Steven Bristow.

“This year we planted a bunch more grafted tomatoes because they were phenomenal. We’re always pleased to work with the University.” – Rob Holley, Holley Family Farms

Their research showed that the plants grafted onto some of the rootstocks had better performance and higher yield in northern Nevada’s variable climate. The grafted rootstocks had better resistance to less-than-optimal temperatures, greater nutrient uptake and bigger growth in northern Nevada’s short growing season. Bristow is working on publishing the results.

A medley of melons

Taking what he learned from studying tomato rootstocks, Barrios-Masias is beginning another rootstock study, this time focusing on melons. In partnership with the Experiment Station’s Desert Farming Initiative and University of Arizona Cooperative Extension in Yuma County, and with a grant from Western Sustainable Agriculture Research and Education, Barrios-Masias hopes to find rootstocks that allow commercial growers to more successfully produce melons in northern Nevada.

Part of the research includes working with Extension’s Associate Professor and Horticulture Specialist Heidi Kratsch. Kratsch will survey Nevada growers to find out whether they’ve tried growing melons or used rootstocks before and what problems they discovered. The results of her survey will inform Masias of issues that may occur during his research, as well as guide his research toward finding rootstocks that can deter pests and avoid diseases.

“There’s a long history of melons in Nevada, dating back to the early 1900s.” - Charles Schembre

Barrios-Masias’s project is one of two melon projects beginning this year at the College. The second project, led by the Initiative’s Project Manager Charles Schembre, aims to improve the success of melon production in northern Nevada through variety trials and mulch tests. With funding from the Nevada Department of Agriculture and through the Experiment Station, he also hopes to provide the technical information growers need to improve their production.

“There is high consumer demand, so we want to help small- and medium-sized farms tap into the market to meet that demand,” Schembre said. “We also simply need to improve our understanding of the process of melon production.”

The three-year project will take place on two plots. The first plot has cantaloupe and honeydew varieties growing under the same conditions. The goal is to determine which varieties grow best.

The second plot will focus on how different growing conditions affect the growth of a few of the varieties. This portion of the test seeks to answer if plastic mulch performs better than no plastic mulch, if different colors of mulch provide better growing conditions, and if melons grow better if they are seeded directly or transplanted. Most of the plot management will be done by Jose Velazquez, who is the lead student intern on the project.

Kratsch, along with Extension Horticulturist and Plant Diagnostician Wendy Hanson Mazet, will be helping with Schembre’s study as well. Their goal is to find out which pests and diseases melons are most susceptible to, and if there are specific varieties that are more susceptible than others. They will be watching for when certain insects arrive and investigating how to treat melons with a holistic, organic approach, since the Desert Farming Initiative is certified organic. Kratsch and Mazet will also help provide information about Schembre’s results to growers and consumers.

Shelf potato

In addition to finding new fruit and vegetable crops for Nevada producers to grow, some researchers are looking for ways to preserve the shelf life of existing crops. Dylan Kosma and Patricia Santos, with funding from the National Science Foundation, are searching for ways to reduce potato crop losses during storage. As the number one vegetable crop in the United States and a top five crop for the state, potato crop losses can be economically devastating to farmers and the potato industry as a whole. A large proportion of these crop losses are due to factors such as rapid water loss and disease while in storage.

The research delves into comprehending how different potato varieties can have different storage lives. They are using one variety that stores very well and another that stores very poorly to understand the molecular basis of this differential storage capacity. Specifically, Kosma is interested in the corky lipid polymer that comprises a large proportion of the skin. This polymer, called suberin, can be found in nearly every plant; however, there is still little known about its makeup and function.

When potatoes are harvested in the field, they tend to get damaged and form scabs, which prevent the sugars and water from coming out and also keeps bacteria and fungi from getting in. This wound-healing tissue is made up of suberin. It is important for potatoes to form this wound-repairing tissue to prolong storage life.

The idea of this research is to ultimately improve how potatoes heal with this wound suberin deposition and how to, in turn, improve their lasting storability.

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