Adapting Chinese Morel Cultivation Strategies for Farmers in the Northeast

Rock Springs Field Site (Penn State) Cropping Trials:

1. Control soil with Morchella importuna
2. Control soil with Morchella rufobrunnea
3. straw-amended soil with Morchella importuna
4. straw-amended soil with Morchella rufobrunnea
5. sawdust-amended soil with Morchella importuna
6. sawdust-amended soil with Morchella rufobrunnea

Soil chemical analyses measured at spawning. Drip line irrigation added. Soil temperatures will be recorded during cropping.

2020

Outdoor morel cropping trials were initiated at the Penn State Rock Springs site in fall 2019. However, due to COVID 19, most personnel and employees were not reporting to campus during the University personnel reduction in March 2020 until June 2020. The spring is a critical time to water and induce morel fruiting in the high tunnel. Unfortunately, no morels fruited and were harvested at Rock Springs, Pa in spring 2020. Student and employee access was allowed starting summer 2020, but with limitations on travel and working in close proximity to one another (and are still in effect). New COVID travel restrictions and limited supplies hindered our ability to install a 2nd high tunnel at Rock Springs and the 1st high tunnel at the University of Maine location (as originally outlined in the grant proposal). However, in fall, 2020 we were able to clean up the high tunnel site at Rock Springs (remove weeds, till and reinoculate the plots with 2 Morchella species (M. importuna and M. rufobrunnea). The plots received 1) no organic amendments 2) chopped wheat straw amendments or 3) oak sawdust amended. On October 5, 2020 the State College high tunnel site was spawned (inoculated) and dripline irrigation was added. Nutrient bags (sterilized sawdust and ground corn) were added to the field plots the last week of October 2020. The plots were irrigated as needed until the weather became too cold and daily freezing temperatures were reached. The plots unfortunately did not yield any mushrooms.

Because we were not able to purchase and install a high tunnel at the University of Maine location, the Univ. of Maine collaborator, Jason Lilley, prepared an existing smaller tunnel on the field location. Soil samples were taken for analysis and the site was prepped by spraying and removing weeds prior to tilling and forming 2 raised beds and dividing the plots by trenching following similar techniques that were implemented at Penn State. Each raised bed consisted of 6 plots (12 plots total - 2 beds x 6 plots). Three treatments were applied consisting of M. importuna mating type MAT 1, M. importuna mating type MAT 2 and spawn consisting of a mixture of both mating types (4 reps each) and incorporated lightly by hand the last week of October, 2020. Nutrient bags (same construction as in Pa) were made and sterilized at Penn State and sent to the University of Maine for application to the inoculated plots. Dripline irrigation was also added and moisture was provided until the temperatures become too cold. Unfortunately no mushrooms formed on these plots.

The outdoor high tunnel at Penn State experiment is investigating the effects of soil amendments and morchella species on yield potential. The outdoor tunnel experiment at the University of Maine is designed to test how mating types affect morel fruit body formation and yield potential. Ascomycetes (of which Morchella belong) typically have different mating types and there is support in the literature suggesting that having both mating types will improve viability of fruit body formation. Therefore, our graduate student Ryan Guo, obtained 7 isolates of Morchella importuna and 9 isolates of Morchella rufobrunnea from the Penn State and the USDA NRRL culture collection to determine mating types so that we could select mating types (MAT 1 and MAT 2) of each species to determine how mating type impacts yield potential. Ryan successfully identified M. importuna isolates of both mating types following protocol found in the literature but is currently still troubleshooting the technique to identify the mating types of M. rufobrunnea (see data table in results section). The results of this work led us to select 2 M. importuna isolates (one MAT 1 and one MAT 2) for the mating type outdoor cropping experiment at the University of Maine.

The mating types of both M. importuna and M. rufobrunnea were determined from the isolates in our collection. The mating types were used in determing which isolates to use to inoculate both indoor and outdoor cropping trials.

Univ of Maine tunnel                                 Penn State University high tunnel

Spring 2021 cropping results at both Penn State University and at the University of Maine both yielded no morel mushrooms.  The research team reassessed the cropping protocol and modified the 2021-2022 experimental design based on new information found in the literature from China.  

2021 Field Cropping

Penn State fall 2021 field crop spawning experiment: Two isolates of each species were chosen based on the results from the mating type work (M. importuna WC 1021 and WC 1022) and two isolates of the M. rufobrunnea were chosen (NRLL 28465 and NRLL 28466).  Grain spawn was made from each of the chosen isolates for inoculation at Penn State University and at the University of Maine.  However, contamination limited the amount of spawn available for cropping so only Penn State University outdoor plots in the high tunnel were spawned October 2021.  Spawn from each individual mating type and a spawn mixture of both strains (species specific) was added to the different plots to determine if species and/or mating type affects fruiting ability and yield. Due to limited spawn supply, only 2 replicates of each treatment were inoculated with Morchella.  Half of the plots were spawned with M. importuna and half of the plots were inoculated with M. rufobrunnea.  Several changes were made to the procedure in the fall of 2021 compared with 2020 to try to account for possible issues contributing to the lack of fruiting success.  In year 2, the amount of spawn used for incoulation was was approximately 3 times the rate previously used and was inoculated in a layer on top of the cultivated soil plots (previously the spawn was incorporated into the cultivated soil), each plot was then covered with approximately 5 cm of "top soil" purchased from a local landscape company and the plots were covered with plastic (to potential increase soil temperatures and to decrease soil moisture loss due to evaporation).  Samples of both soils were sent to Penn State's agricultural analytical lab for chemical analyses.  Drip line irrigation was added and black plastic was used to cover the plots (also a change from previous cropping attempts).  Early visual observations noted a much higher rate of surface colonization than what was previously observed in outdoor cropping trials. 

Additional spawn was produced (after contamination issues were noted), stored at 4C and was used for outdoor inoculation during spring 2022 at the University of Maine field plot (the timing was based on soil and air temperatures). Unfortunately due to contamination, fall inoculation was not achievable.  Yield results for both can be found below.

Indoor cropping

An indoor cropping experiment was started January 2022.  Soil was collected from the Penn State University farm site (soils previously used by the Pecchia lab for indoor cropping trials) and steam pasteurized at 60C for 12 hours to eliminate potential pests. Additional topsoil was also pastuerized prior to using for the indoor cropping trial.  The same treatments (species and strains) used in the outdoor cropping trials were chosen for the indoor cropping trial.  However, only M. importuna strains were used for indoor cultivation trials due to contamination of the M. rufobrunnea spawn bags.  Individual and combined M. importuna mating types were inoculated into different gray tubs that each contained 22.5 kg soil per tub.  Indoor cropping treatments consisted of either M. importuna Mat 1-1-1 mating type, Mat 1-2-1 mating type or a combination of Mat 1-1-1 and Mat 1-2-1 mating types, all at a 1 x or 3x spawn rate with 5 replicates of each treatment. Once spawned, topsoil and nutrition bags as well as black plastic was used to cover the tubs, similar to the protocol used in the outdoor high tunnel.  Room environmental conditions were set to 16C, 90 % humidity and the lights were programmed on a diurnal light cycle.  The time from spawning to harvesting mature fruit bodies indoors was approximately 120-130 days. Yield results can be found below.