Progress report for SW20-918
Project Information
Nevada farmers are challenged by a short growing season and slow crop establishment of warm-season vegetables. Yet, increased demand for local produce in nearby urban areas presents an opportunity to diversify farms while adapting to climate uncertainty. Although melons perform well in arid climates, producers express that slow root growth and diseases affect production. Growers could rely on grafted melons, but information on which and how rootstocks can improve management does not exist for local growers. This project integrates farmers’ interests in a series of greenhouse research and on-farm trials in Northern Nevada and Yuma, Arizona, which is also an arid region, but it has a well-established melon industry that could benefit from adoption of grafting to reduce disease incidence and increase productivity.
Objectives:
- Evaluate and select melon rootstocks that enhance early crop establishment and performance of grafted cultivars under desert climates.
- Determine how selected rootstocks can affect melon cultivar yields and fruit quality under different management and on-farm conditions (e.g., mulching and irrigation).
- Conduct a survey of specialty crop farms (organic and conventional) to evaluate the needs and concerns of growers from the perspective of crop diversification and sustainability.
- Conduct annual educational outreach activities to communicate with stakeholders on research progress and acquire feedback for future research activities.
Outcome indicators:
- Identify at least two rootstocks and the mechanisms by which they confer better crop establishment and higher yields than own-rooted cultivars.
- Produce three annual fact sheets and two scientific articles with results regarding melon rootstocks, mulching, water management alternatives, and survey outcomes to increase awareness of producers and other stakeholders on crop diversification and adoption of practices to overcome biotic and abiotic stresses.
- Adoption from 30% of local producers of rootstock technology directed to improve crop establishment and yields. In the short term, local growers in Nevada and Arizona will likely adopt this technology, but we expect to stimulate nationwide interest.
- One graduate student and at least five undergraduates will acquire theory and hands-on training in areas necessary for success in their careers.
- Evaluate and select melon rootstocks that enhance early crop establishment and performance of grafted cultivars under desert climates.
Task 1: Screen multiple rootstocks and determine the root morphological and physiological traits that improve cultivar performance.
Task 2: Assess how shoot physiological performance of a grafted cultivar is affected by rootstocks (e.g., leaf gas exchange and yield).
- Determine how selected rootstocks can affect melon cultivar yields and fruit quality under different management and on-farm conditions (e.g., mulching and irrigation).
Task 1: Evaluate crop physiological performance, disease tolerance and yields of the producer’s choice cultivars (i.e., scions) grafted on rootstocks selected from Obj. 1.
Task 2: Evaluate alternative management practices (e.g., mulching and irrigation) to enhance crop establishment and performance.
- Conduct a survey of specialty crop farms (organic and conventional) to evaluate the needs and concerns of growers from the perspective of crop diversification and sustainability.
Task 1: Develop a survey tool in year one to administer to all specialty crop growers in Nevada.
Task 2: Administer the survey in year 2 and use the results to fine-tune the nature of our education and outreach activities.
- Conduct annual educational outreach activities to communicate with stakeholders on research progress and acquire feedback for future research activities using the WSARE survey and evaluation tool.
Task 1: Produce one extension fact sheet per year.
Task 2: Conduct one field day per year at university and producers’ fields (years 2 and 3).
Task 3: Disseminate results through local, regional and national conferences and workshops.
The table below provides the list of activities necessary for the success of the project in a timely manner and within the three year timeframe. Activities are presented in order of first occurrence although they may repeat in subsequent years (black cells). Activities that include on-farm trials and field days include the State where they will be occurring (i.e., NV and AZ).
Cooperators
- - Producer
- - Producer
- - Producer
- - Technical Advisor
- - Producer
Research
Objective 1. Evaluate and select melon rootstocks that enhance early crop establishment and performance of grafted cultivars under desert climates.
Hypothesis 1.1. From the nine rootstocks to be evaluated in 2021, at least one rootstock will enhance early canopy development and establishment, which should result in improved yields in regions with short growing seasons as in Northern Nevada.
Objective 2. Determine how selected rootstocks can affect melon cultivar yields and fruit quality under different management and on-farm conditions (e.g., mulching and irrigation).
Hypothesis 2.1. Plastic mulch may positively affect how some rootstocks influence cultivar (scion) development, growth rate, disease resistance and yields.
Hypothesis 2.2. At least one rootstock should improve cultivar (scion) performance under lower irrigation volumes and result in higher water use efficiency without a decrease in yield.
Objective 1. Evaluate and select melon rootstocks that enhance early crop establishment and performance of grafted cultivars under desert climates.
This objective is currently in progress as we establish our first field trials. We did not conduct trials in 2020 due to the pandemic. Two locations have been identified in Nevada: Lattin Farms in Fallon, and the UNR Valley Road Research Station in Reno. In addition, a field trial has been established at the Yuma Ag Research Center, AZ in early April, 2021. The Barrios Lab in collaboration with our collaborators from Plug Connection selected a total of nine rootstocks to screen (Task 1). All rootstocks are grafted with the same cultivar (scion). The varieties selected were Sarah's Choice and Caribbean Gold for Nevada and Arizona, respectively. Varieties were selected based on performance and preference in each location.
In 2022, field trials were conducted in Reno and Fallon, NV, with four selected rootstocks from the 2021 field trials. The field trials were conducted as in 2021 with the difference that plastic mulch was used in the Reno trial because weed pressure is high and melon growers do use plastic mulch in their farms.
Measurements conducted in the Nevada field trials were: soil canopy cover using an agricultural digital camera, stomatal conductance using a porometer, plant water potential with a Scholander pressure chamber, and biomass evaluations for several weeks as fruit ripened and a final harvest of all shoot and fruit remaining. In addition, fruit quality (e.g., Brix and color) was evaluated for the experiment conducted in Reno at the UNR field station.
Objective 2. Determine how selected rootstocks can affect melon cultivar yields and fruit quality under different management and on-farm conditions (e.g., mulching and irrigation).
For the 2022 season, the Reno field trial included two irrigation treatments using the same plant material used for Obj. 1. The treatments were based on the use of soil moisture sensors to optimize and reduce irrigation by replenishing soil moisture to field capacity (i.e., 100%) or to only 70% of maximum soil moisture content. Soil moisture was monitored at 20 and 40 cm deep. In addition, greenhouse and field trials were conducted to understand thresholds of water deficit in melon plants. Plants were monitored under well-watered conditions and drought stress by reducing or stopping irrigation until severe wilting was observed. Measurements included pre-dawn and midday water potentials, and leaf gas exchange measurements with a Licor-6400. The latter measurements would allow us to understand plant physiological thresholds under drought stress that could help optimize water management and crop productivity.
Objective 3. Conduct a survey of specialty crop farms (organic and conventional) to evaluate the needs and concerns of growers from the perspective of crop diversification and sustainability.
Task 1: Develop a survey tool in year one to administer to all specialty crop growers in Nevada.
Task 2: Administer the survey in year 2 and use the results to fine-tune the nature of our education and outreach activities.
In this past year, efforts were directed to this objective. Task 1 has been completed as a survey was developed among the project team and tested online. Currently, the survey is in its last round of reminders to potential participants, and it has reached a 35% response rate in Nevada based on the number of vegetable farmers as reported in the USDA-NASS census data. The survey was also distributed in Yuma County, AZ, but the response rate has been extremely low. Distribution of the survey was done electronically with three round of emails sent to listserv managed by the Desert Farming Initiative at UNR and the nonprofit corporation Nevada Grown.
Results from the survey have been partially analyzed and are being prepared for a publication. Results will be presented in the ASHS 2022 annual conference to be conducted in Chicago, IL, between July 30 and August 3, 2022.
During 2022, the publication based on the survey results was submitted as a special publication to UNR Extension. The publication title is “Enhancing Production of Warm-Season Crops in Nevada Using Rootstocks: A Grower Survey”, and it is currently in the final stages for publication.
Objective 1. Evaluate and select melon rootstocks that enhance early crop establishment and performance of grafted cultivars under desert climates.
In 2021, two field trials were conducted in Northern Nevada. Preliminary data evaluation shows that cantaloupe production was different in Reno and Fallon areas. There was a significant interaction between field and phenotype (grafted and ungrafted plant material) for several variables. For instance, yields tended to be higher in Reno, but fruit quality was qualitatively better and more consistent in Fallon, which also produced larger fruits. The ungrafted cultivar (Sarah's Choice) did better in Fallon than several grafted phenotypes but poorly in Reno.
In addition, greenhouse and field trials have been conducted to understand cantaloupe water relations under low water availability. This has been accomplished by conducting root hydraulic measurements of all plant material (10 phenotypes). Preliminary data did not show major differences among phenotypes. Preliminary field trials were conducted to understand the relationship between pre-dawn and midday water potential. The aim is to understand critical points related to soil water availability and evaporative demand when drought stress compromises plant performance. These trials could support irrigation management decision linked to plant physiological performance.
The results from the 2021 trials were used to select four rootstocks to be used in the 2022 experiments (five phenotypes; four grafted and one ungrafted plant material). Rootstocks were selected based on scion performance and differing characteristics (e.g., fruit number and harvest pattern), considering that their performance fluctuated in the two locations where they were grown (Reno and Fallon, NV). This plant material will be also evaluated under two irrigation regimes (i.e., Obj. 2).
Objective 2. Determine how selected rootstocks can affect melon cultivar yields and fruit quality under different management and on-farm conditions (e.g., mulching and irrigation).
Preliminary results suggest that the ungrafted melon improved its crop water productivity under 70% irrigation compared to 100% irrigation. Yet, the reduction in irrigation volume (i.e., 70% treatment) did not affect the yield of any of the phenotypes, which suggests that melons tolerate controlled-reductions in irrigation volumes. Poster from the ASA-CSSA-SSSA 2022 meeting presenting this results is available here: diSanto_ASA-2022_Poster
Objective 3. Conduct a survey of specialty crop farms (organic and conventional) to evaluate the needs and concerns of growers from the perspective of crop diversification and sustainability.
Our preliminary analysis of the survey suggests that growers in Nevada are interested in trying rootstocks for warm-season vegetable production, but adoption of the technology will require a cost-benefit analysis of using rootstocks as an alternative to conventional production methods.
Objective 4. Conduct annual educational outreach activities to communicate with stakeholders on research progress and acquire feedback for future research activities using the WSARE survey and evaluation tool.
We conducted one field day at Lattin Farms, Fallon, NV, and a presentation at the ASHS is scheduled for August, 2022. Unfortunately, due to the pandemic, the local Nevada Farms Conference has not been conducted in the past two years. We have had students from the Principles of Horticulture class visit the field and listen to Heinrich di Santo (graduate student) about the objectives of the research.
In 2022, our research results have been shared in formal and informal meetings. The main local conference has not been organized after the pandemic. Yet, graduate student, Heinrich di Santo, has presented in local (UNR) and national venues (ASA-CSSA-SSSA 2022 meeting), and Dr. Kratsch presented the survey results in the ASHS 2022 conference.
Research Outcomes
Preliminary data shows that the use of grafting for Cantaloupe melons in the high desert does not provide a consistent advantage over the ungrafted cultivar. Location and year had a strong effect on yield, fruit weight and fruits per plant; even though the 2022 season was overall a year with lower yields for our research and farmers in the area (personal communication). Fruit quality (Brix°) was consistently one of the highest in the ungrafted cultivar. An observation, which needs further evaluation, is that the pattern of harvest can change based on grafting and rootstock, and this may provide an advantage for local growers who may benefit of a more consistent production of melons during the 4-6 weeks of harvest.
We do see potential in the response to reductions in irrigation volume based on soil moisture content. We are conducting a second year to validate the 2022 results. The use of soil moisture sensors to maintain soil moisture above the maximum soil water depletion level (i.e., >55% of soil water content; FAO paper No 56) and reductions in irrigation volume could result in water savings for growers and increase water use efficiency without reductions in yield.
Education and Outreach
Participation Summary:
Year 2020:
A newsletter article including this project was published on June 17, 2020 (https://www.unr.edu/nevada-today/news/2020/fruit-and-vegetable-research).
The total number of participants for the survey (Obj. 3) as of 4/12/21 is 38 people.
Year 2021:
- Field day in Fallon, NV at Lattin Farms on 08/22/21 - An informational sheet was distributed among participants showing yield progress at both fields. Participation was low because of smoke conditions due to California wild fires.
- Class presentation: Students from the Principles of Horticulture class visited the field in Valley Rd. Research Station at UNR. Heinrich di Santo, graduate student, shared the objectives and progress of the project.
Year 2022:
- Graduate student presentation on 03/22/22: Three Minute Thesis Competition at UNR.
- ASHA 2022 Annual Conference: "Enhancing Production of Warm-season Crops in Nevada Using Rootstocks: A Grower Survey".
- Manuscript accepted based on survey results. Currently in press:
- Kratsch, H.A., F. Barrios-Masias, and B. Poudel-Ward. 2023. Enhancing Production of Warm-Season Crops in Nevada Using Rootstocks: A Grower Survey. University of Nevada, Reno Extension SP-23-01 (11 pp).
- Graduate Poster Symposium at UNR on 10/27/22.
- ASA-CSSA-SSSA 2022 International Annual Meeting (11/08/22): "Could melon grafting and deficit irrigation enhance yield and crop water productivity in high desert environments?"
- Dr. Poudel-Ward shared information about the project in three master gardener classes with an attendance of ~20 people per session.
Education and Outreach Outcomes
Information Products
- Enhancing melon production and adaptation in high desert environment through grafting on squash hybrid rootstocks (Conference/Presentation Material)
- Field Day Informational Sheet (Conference/Presentation Material)