Huitlacoche Production as an Alternative Crop in South Texas

Huitlacoche Production as an Alternative Crop in South Texas

Summary

Continued investigations for the commercial production of huitlacoche in corn again resulted in only one effective method – silk-channel inoculation.  New techniques to culture the huitlacoche fungus as an inoculant were tested, but as in previous trials, the only inoculant to produce huitlacoche was that created with pure strains of the huitlacoche fungus, Ustilago maydis. Corn cultivar did not play a large role in the amount of huitlacoche produced, but preventing pollination by de-tasseling was again critical for the production of huitlacoche in a substantial amount. 

Objectives/Performance Targets

To introduce huitlacoche to a larger portion of the American market requires the development of reliable methods that will allow for the production of larger quantities that a grower in the South can market over the entire growing season. Several factors can affect the production of huitlacoche. Among them are determining which spore source creates the best or most effective inoculant and discovering if certain varieties of corn are more susceptible or produce more huitlacoche than others. The research is necessary to be able to produce huitlacoche commercially and provide an alternative crop that will help small-scale growers in the South to remain economically sustainable.

This project’s three research objectives will be carried out simultaneously over the course of four growing seasons (two years) as follows:

1. Determine what sources of huitlacoche spores provide the highest success rate for propagation.

In order to inoculate corn, huitlacoche spores must be gathered. Sources of huitlacoche spores will include frozen huitlacoche, fresh huitlacoche, and pure culture strains of the huitlacoche fungus, Ustilago maydis. Frozen huitlacoche will be purchased from an online source, and fresh huitlacoche will be culled from naturally occurring huitlacoche in corn. Pure culture strains of U. maydis will be obtained from researchers at the University of Illinois. A sporidial suspension will be produced with each of these sources and used to inoculate corn in order to determine its viability as an inoculum. Percentage of corn in which huitlacoche develops will be evaluated. The steps involved in determining the best spore source for huitlacoche propagation include:

a. Investigate and collect possible sources of huitlacoche spores.
b. Create and maintain sporidial suspensions with each spore source.
c. Inoculate corn using each spore source.
d. Assess percentage of corn in which huitlacoche develops.

2. Determine what varieties of corn are best suited for huitlacoche propagation.

Some varieties of corn may be more prone to developing huitlacoche than others. To determine which varieties are best suited for huitlacoche production in South Texas weather conditions, three varieties identified as being suitable for huitlacoche production will be planted and inoculated with each of the spore sources previously described. The trials will be conducted through four growing seasons (spring and fall 2013 and spring and fall 2014). Steps required to determine which varieties of corn are most suitable for huitlacoche production include:

a. Plant three corn varieties that research has shown are the most appropriate for                 huitlacoche propagation.
b. Inoculate each variety with each spore source.
c. Evaluate the number of plants and ears that produced huitlacoche in each variety.

3. Disseminate findings to local growers through outreach efforts.

A major objective of this Research Project is to share the knowledge gained with small-scale producers in the South so that they may be able to grow this alternative crop and sell it for a premium price through direct-marketing channels. Outreach efforts will begin by reporting results on the University’s outreach website and continue with the production and broadcasting of a project video. The project video will be produced and broadcast on a regional television station by Valley Telephone Cooperative. The University also operates a number of USDA-funded outreach projects that will provide effective outreach for project research. Training events will be conducted by the University and its resource partners, including University outreach projects funded by USDA Office of Advocacy and Outreach (OAO), National Institute of Food and Agriculture (NIFA), and Natural Resources Conservation Service (NRCS). During the training events, growers will be informed of the best spore source, corn variety, and inoculation technique to use in order to grow huitlacoche successfully. Instructions and demonstrations will be presented on how to create the sporidial suspensions and how to inoculate the corn. The steps required to fulfill this objective include:

a. Create a report for the University website and update it as findings become available.
b. Produce a video detailing the Project and all of its components.
c. Broadcast the video on a regional television station.
d. Conduct training events for local growers.

Accomplishments/Milestones

In the spring and fall of 2014, trials for the production of huitlacoche were conducted at two research sites.  Both sites are cooperator farms located in Lyford, Texas.  All methods tested and described below were identical at both locations.  As in the previous year’s trial, three corn cultivars and three types of huitlacoche inoculum were tested; however, only one inoculation technique was implemented after poor results with two other techniques tested the year before.  Inoculum type played a significant role in the development of huitlacoche, while the role corn cultivar played was not as significant.  Data was only collected from the spring 2014 crop as a severe beet armyworm infestation in the fall of 2014 completely destroyed the crops at both locations and made any testing impossible that season. 

The only method used in the 2014 trials to inoculate the corn with the huitlacoche fungus was silk-channel inoculation, where the inoculum is injected directly into the ears of corn.  Previously, two other inoculation methods had been tested: applying the inoculum to abraded tissue at the base of the corn plants, and injecting the inoculum into the developing leaf swirl of the plants.  These two methods failed to produce any huitlacoche and so were not tested any further.  Silk-channel inoculation was the only method that had previously produced huitlacoche and was therefore used in the 2014 trial.  This method continued to be extremely effective in producing huitlacoche, with a 68% – 86% inoculation success rate. 

The source or type of huitlacoche spores used to create an inoculum played a major role in the production of huitlacoche.  The three inoculants tested in the 2013 trials were tested again.  Two of these inoculants failed to produce huitlacoche in any substantial amount previously, but were tested again to definitively rule them out as a possible choice of inoculant.  The first inoculum was created by drying and grinding fresh huitlacoche galls gathered from an area corn field in the fall of 2012 and incubating the resulting powder in a nutrient broth for 24 hours at room temperature before being used.  The second inoculum was created by blending frozen huitlacoche galls purchased from an online source in a nutrient broth and incubating the inoculum for 24 hours at room temperature before being used.  These two spore sources were both used in the 2013 trials, but they only produced a few incidental huitlacoche galls; however, they were both mixed with water immediately before use in the 2013 trials, so in 2014 the spores were instead incubated in potato dextrose nutrient broth for 24 hours in the hopes of producing more huitlacoche with these two spore sources.  The third inoculum was prepared by combining two pure-culture strains of the huitlacoche fungus, Ustilago maydis, and growing them in a potato dextrose nutrient broth.  The corn inoculated with the pure culture strains were the only ones in which any huitlacoche developed.  No huitlacoche galls developed in ears inoculated with either the dried or frozen galls as in the 2013 trials.   

To help determine if corn cultivar plays a role in the development of huitlacoche, three corn cultivars were again tested based on their resistance to U. maydis: ‘Golden Bantam’, ‘Silver Queen’, and ‘Golden Jubilee’.  ‘Golden Bantam’ and ‘Silver Queen’ had been tested in previous trials, but no definitive conclusion could be made about their role in huitlacoche development.  In the 2014 trial, 68% of inoculated ‘Golden Bantam’ ears and 86% of inoculated ‘Silver Queen’ ears produced huitlacoche, compared to 61% in Golden Bantam and 58% in ‘Silver Queen’ in the previous year’s trial.  82% of inoculated ‘Golden Jubilee’ ears produced huitlacoche.  Despite the difference in inoculation success rates, the amount of huitlacoche produced per ear was nearly the same for all cultivars: 0.23 lb/ear for Golden Bantam and 0.24 lb/ear for ‘Silver Queen’ and ‘Golden Jubilee’ (Table 1).  At this point in the research, it appears that operator technique and the precision he uses in injecting the inoculum may play a larger role in inoculation success rate and the amount of huitlacoche produced than the cultivar of corn being used.  

As in previous trials, silk-channel inoculation was very effective in producing huitlacoche, but only those ears injected with the pure culture strain of the huitlacoche fungus, Ustilago maydis, produced huitlacoche.  Incubating fresh and frozen U. maydis spores in a nutrient broth was not effective in producing huitlacoche when injected into the corn ears.  Operator technique played a larger role than corn cultivar in the production of huitlacoche.  In summary, silk-channel inoculation of pure cultures of U. maydis is the only method that has produced huitlacoche in any substantial quantity over the two year course of this project. 

The most pressing concern at the end of the first year’s trial was to identify a method to keep the pure cultures of Ustilago maydis alive from season to season without storing them in a -80°C freezer, something not usually available to most growers.  Furthermore, while producing the U. maydis inoculum is not a difficult process, it also requires the use of a laboratory and laboratory equipment.  These issues continue to be a concern for this project.  To date, no alternative storage method has been found that would make it feasible for a grower to use pure culture strains of U. maydis to produce huitlacoche reliably.  Also, while silk-channel inoculation is extremely effective at producing huitlacoche, it is very time consuming and perhaps not very feasible on a large scale.  To address this issue, future trials could include inoculating the corn by spraying the inoculum onto the corn silk using a back-pack or similar type sprayer.  This method would certainly be less time consuming, but data would have to be collected to determine its effectiveness in producing huitlacoche in a substantial quantity. 

A no-cost, one year extension has been approved to continue researching methods for the production of huitlacoche.  Special emphasis will be placed on developing methods that would allow growers to produce huitlacoche without the need of a lab or specialized laboratory equipment.  Furthermore, organic huitlacoche production will be researched during 2015 at a new cooperator site, Terra Preta Farm in Edinburg, Texas.  This experiment will test two planting techniques – the three sister’s poly-culture and a regular monoculture.  Two types of corn, dent (‘Oaxacan Green’) and sweet (‘Luscious’), will be grown and sprayed with Ustilago maydis cultures.  Squash and bean will be grown alongside the corn to complete the three sister’s poly-culture.  In summary, three variables will ultimately be tested in this experiment – two planting techniques (poly-culture vs. monoculture), two corn types (dent vs. sweet), and artificial spraying (spray vs. unsprayed).  

• Table 1
• huitlacoche3
• huitlacoche2
• huit

Impacts and Contributions/Outcomes

Since being published in two national agriculture magazines (Southwest Farm Press and Farm Show) in 2013, this project has continued to garner requests for more information from growers, including several in Louisiana and Indiana.  One grower in Louisiana has a standing order from three high-end restaurants to buy any huitlacoche he might be able to produce.  A most unusual request for more information came from a prison inmate who wanted to farm his land and hoped to grow huitlacoche upon his release from prison.  It is clear that interest remains high from both growers wanting to cultivate huitlacoche and restaurant owners/chefs who would like to find local growers who can supply fresh huitlacoche to them. 

The University of Texas – Pan American’s (UTPA) Center for Rural Advancement (CRA) has developed a specialty-crop commercialization video that highlights its community-based participatory research on huitlacoche.  The half-hour video was developed by a UTPA College of Business Administration marketing student and a biology graduate student. In the first half of the video, a background and analysis of the huitlacoche fungus is provided.  The second half of the video is a commercialization panel discussion that includes both students and two biology and business faculty members. This video has been repeatedly broadcast over rural South Texas on VTCI’s television channel.  The video can also be viewed at http://youtu.be/0nSrkquP0yA.  Through the video production, CRA was able to employ students while they engaged in a truly experiential and multidisciplinary learning experience. The video production marks the CRA’s fourth student-produced video in a series called “Rural Ventures”, and supports CRA’s efforts to hire students to engage in experiential learning while supporting the economic, social, and environmental advancement of rural areas and the well-being of the people that live in these areas.   

Since the inception of this research, this project has had several set-backs, including non-viable Ustilago maydis cultures and crop destroying pests, which have impeded the University’s ability to provide on-site demonstrations for local growers.  A no-cost, one year extension has been approved to continue research on developing techniques for the production of huitlacoche.  Outreach activities to share this information will continue.   

The press generated by this project has farmers and chefs excited about the prospect of a new specialty crop that would allow them to increase their profits and economic sustainability by allowing them to charge premium prices for huitlacoche, which sells for a much higher price than the corn on which it grows. In the United States, huitlacoche has been gaining in popularity, thanks in part to the increasing Mexican American population and also because of American consumers’ new affinity for or willingness to try new and exotic foods.  With increased product demand and a high market price, cultivation of huitlacoche has the potential to provide sustainable, small-scale growers enough income to increase their economic sustainability.     

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