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.
In 2023, two field trials were conducted. One trial aimed to compare how the use of plastic or paper mulch could affect plant establishment and yield of a common scion (Sarah's Choice) grafted onto a rootstock (Carnivor) and ungrafted as a control. The second field trial expanded on the previous year's research on reduced irrigation. We added one more irrigation treatment to evaluate plant performance under a more extreme condition: soil moisture of 50% of the maximum soil moisture content. The other two treatments, as in 2022, were irrigation treatments to achieve 100% and 70% of maximum soil moisture content per irrigation. Soil moisture monitoring and measurements were similar to the previous year. In addition, we conducted one greenhouse trial to increase our dataset for understanding thresholds of water deficit in melon plants. The latter was also conducted under field conditions, which included two beds where soil moisture was manipulated to drought stress plants and measure a wide range of water deficit (plant stem water potential) and soil water potential.
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.
In 2023, our survey results were published as a special publication through UNR Extension.
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).
In 2023, a greenhouse and a field trial were conducted to collect data on plant water relations as it had been done in previous years. These data was presented at the ASA-CSSA-SSSA 2023 conference, and shows thresholds (e.g., loss of turgor) due to plant water stress as determined by predawn plant water potential and physiological performance during the day (e.g., photosynthetic rates). A manuscript is under preparation for submission in 2024. In addition, the manuscript based on the 2021 and 2022 rootstock trials has been written, and it should be submitted to a peer-review journal by March 2024 (submitted to HortScience; under review). Our results show that rootstock performance was dependent on location and year, and suggests that most rootstocks did not provide an advantage on higher yield in the high desert. Moreover, some rootstocks decreased fruit quality (Brix) and the ungrafted control consistently produced melons with higher sweetness.
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
2023 and 2022 data are in line and suggest that a reduction in irrigation volume of 30% from ETc, using soil moisture sensors, does not impact yield and can increase crop water productivity (CWP). The 50% irrigation treatment had significant reductions in yield compared to the 100% and 70% irrigation treatments although CWP was higher than the 100% irrigation treatment. The 50% irrigation treatment was important to evaluate field thresholds in plant water relations. These data is being analyzed and will result in a manuscript. Partial results are shown in the poster presented at the ASA-CSSA-SSSA 2023 meeting and is available here: diSanto CSSA-2023 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.
Our findings are being reported in our Extension publication (see below).
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.
In 2023, our research results were shared in formal and informal meetings. We participated at the annual Fallon Cantaloupe Festival and Country Fair (Aug. 2023), where we conducted fruit sweetness test with participants (measure Brix) and presented a poster on our melon research (Cantaloupe Festival - 2023). Dr. Poudel shared information about our melon project in three Master Gardener events at Yuma, AZ. Heinrich di Santo, graduate student in the project, presented in local (UNR) and national venues (ASA-CSSA-SSSA 2023 meeting). The latter included an oral and a poster presentation. In addition, Dr. Barrios-Masias presented at the ASHS 2023 conference an oral and a poster presentation (ASHS 2023 - Melon-Grafting-SMALL).
Research Outcomes
The data collected in three years of research show that grafting for Cantaloupe melons in the high desert did 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 impact of year in crop performance was drastic between 2021 and 2022 (yield decrease of ~50% in 2022). Similar decreases in yield were observed for cucurbits in other local farms (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 over time can change based on grafting and rootstock. Number of harvests and peak harvest times may provide an advantage for local growers who may benefit from a more consistent melon production during the 4-6 weeks of harvest.
We do see potential on improving water management based on the melon performance and yields under reduced irrigation volumes, which are estimated from soil moisture content. We conducted two years of research trials, and reductions in 30% irrigation (i.e., 70% irrigation treatment of maximum soil water content) maintain yields and increased crop water productivity. 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. Integration of soil moisture data and physiological thresholds of melons under drought stress can support increased water use efficiency in melons and other vegetable crops.
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". ASHS poster 2022_Kratsch
- 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). SP-23-01
- 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.
Year 2023:
- Nevada Field day in Reno, NV at UNR on 06/02/23 - Shared work on vegetable grafting with the general public. Showed melon grafted plants and provided free plants to attendants.
- ASHA 2023 Annual Conference (oral): "Melon variety trials under two crop mulch types in a high-desert climate".
- ASHA 2023 Annual Conference (poster): "Considerations in Melon Grafting Performance, Yield, and Fruit Quality in High-Desert Climates".
- Fallon Cantaloupe Festival and Country Fair (08/25-26/2023) - We had a booth to present results from our research, interacted with attendants, and had a hands-on demonstration on fruit quality (Brix).
- Class presentation: Students from the Principles of Horticulture class visited the field in Valley Rd. Research Station at UNR. Dr. Barrios explained objectives of the project and students observed melon performance under plastic and paper mulch.
- Master gardener outreach by Dr. Poudel from The University of Arizona Cooperative Extension (three events; Yuma AZ).
- ASA-CSSA-SSSA 2023 International Annual Meeting (10/29/23; oral): "Predawn and midday water potential relationship in melons under drought conditions".
- ASA-CSSA-SSSA 2023 International Annual Meeting (10/31/23; poster): "Cantaloupe physiological responses to deficit irrigation and impacts on crop water productivity".
Year 2024:
- Present at the NV Small Ag Conference in Fallon, NV (03/14/2024; already in conference program): "Updates on Cantaloupe melon and tomato trials evaluating vegetable grafting, irrigation and nitrogen management". NV-SmallFarm-Conference_2024
- Create a webpage on the UNR Extension website dedicated to results of our work with melons, linking melon extension publications on this page and promoting webpage visits through our social media outlets https://naes.unr.edu/dfi/publication.aspx?PubID=5520
- di Santo and Barrios-Masias (under review) Melon Grafting Effects on Plant Performance and Yield in the High Desert.
Education and Outreach Outcomes
Understanding the needs of the target audience is important to deliver information relevant to stakeholders. In the vicinity of Reno, NV, most vegetable farmers are managing small farms, and mainly high tunnels, where other vegetables and fruits are more profitable for their business than melons, which require a larger production field. Our local outreach efforts were affected by the pandemia and the cancellation of the Farm Conference, which congregates a good number of our target farmers. Our outreach and educational activities will continue in 2024, as these have lagged behind our research, and we have just now more concrete results to share with farmers (see Education and Outreach Methods for 2024). Yet, through workshops and informal conversations with stakeholders, this project created awareness on and interest in vegetable grafting and soil moisture sensors to determine irrigation needs for small-scale farms. We have identified that soil moisture monitoring is a higher priority for local farmers as they aim for improving sustainability in a water-scarce landscape.
- Rootstock impact on cantaloupe performance and fruit quality
- Reduced irrigation
- Plastic vs paper mulch effects on melon performance
- Vegetable grafting (cantaloupe)
Vegetable grafting