Final Report for OS13-072
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.
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. This 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:
- 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 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
In the spring of 2015, trials for the production of huitlacoche were conducted at three research sites. All three sites are cooperator farms located in Lyford and Raymondville, Texas. Previous research indicated that silk-channel inoculation was the only method to have effectively produced huitlacoche, with a 68%-86% inoculation success rate, with ‘Golden Bantum’ and ‘Silver Queen’ varieties having adequate susceptibility to huitlacoche pathogenicity. Therefore, three corn cultivars: ‘Silver Queen’, ‘Golden Bantum’, and flint, were tested in these trials, with special emphasis being placed on developing methods that would allow farmers to produce huitlacoche without the need of a lab or specialized laboratory equipment. For this reason, new, less strenuous methods were used in this investigation. The new inoculation methods that were examined during this trial included manure, soil, and homemade broth examinations
Four separate trials were conducted in spring 2015 all examining possible huitlacoche occurrence using more practical inoculation methods. The first trial conducted in Lyford, Texas examined the possibility of huitlacoche occurrence with the use of manure, soil, and spores as parameters. Research indicates that huitlacoche spores can overwinter and are found in soil. Moreover, manure can be a possible host of spores as well. Due to this information, inoculations with soil and manure were chosen for this trial. The inoculations were made shortly after the corn was at the mid-silk stage, and via the silk-channel. The plot in which this trail was being conducted, however, suffered from a severe beet army worm infestation, causing significant damage to every ear of corn and completely inhibited any possible huitlacoche from occurring.
The next trail conducted focused on producing homemade broths with huilacoche spores. Based on the previous year’s results, artificial inoculation was the only successful inoculation technique known to produce huitlacoche in corn in South Texas. Using this information, a homemade inoculum was derived that included huitlacoche spores mixed in a potato-corn syrup broth. The potato-corn syrup broth derived for this trail was to simulate the potato-dextrose nutrient broth that cultures the fungus, and which was used in the successful artificial inoculation trials. The purpose of the broth is to provide nutrition to the spores and to theoretically cause them to germinate to their pathogenic state. The broth mixture was inoculated into the corn shortly after mid-silk, via the silk-channel, using a modified backpack sprayer. This strategy yielded 0% infection rate, and was also considered a nonviable way to produce huitlacoche. This trial initially suffered from severe red-winged blackbird predation during the germination stage that could only be managed by completely inclosing the young plants with chicken-wire fencing.
Two additional trials were conducted at cooperator farms, each testing potential practical inoculation methods. The first additional trial, conducted near Lyford, Texas, focused on the possibility of cow manure manifesting appropriate conditions for huitlacoche pathogenicity. Spores were incorporated into manure/potato broths and inoculated into the corn via silk-channel inoculation during mid-silk, at three-quarter silk, and at full silk. This strategy yielded 2% success rate and was considered a nonviable way to produce huitlacoche. Moreover, the second additional trial conducted in Lasara, TX, focused on pathogenicity under natural occurrences. The spring of 2015 featured uncharacteristic rainfall and storms. The heavy rainfall caused the Lasara plot to be completely flooded in water and enabled study of the effects of flooding on huitlacoche pathogenicity. Spores were released into the flood water at various locations on the plot just before mid-silk and the effects on the corn were observed. This strategy yielded 0% infection rate, and was also considered a nonviable way to produce huitlacoche. The corn cultivars used for the Lyford and Lasara plots were, ‘Golden Bantum’ and ‘Silver Queen’.
Additionally, in the spring of 2015, organic huitlacoche production was also an area of interest to be researched at a new cooperator site, Terra Preta Farm in Edinburg, Texas. In this experiment, two planting techniques were used; the three sister’s poly-culture and regular monoculture. The three sister’s poly-culture included squash and beans that were grown alongside the corn. Furthermore, two corn types, dent (Oaxacan Green) and sweet (Luscious), were grown in order to be artificially sprayed with Ustilago maydis cultures. In summary, three variables were to be examined—the two planting techniques (poly-culture vs. monoculture), the two corn types (dent vs. sweet), and artificial spraying (spraying vs. unsprayed). This trial was intended to be conducted using only organic approved farming techniques in a certified organic farm in the Rio Grande Valley of South Texas. Important beneficial practices in an organic setting were to include; maintain fostered soil conditions by using crop rotation, cover cropping, composting, full prohibition of synthetic herbicides, and the use of integrated pest management for insect control. However, this organic Huitlacoche trial was destroyed by cottontail rabbits and red-winged blackbirds and did not produce results.
Interest in Huitlacoche as a potential alternative crop in South Texas has garnered the attention of national agriculture magazines such as Southwest Farm Press and Farm Show, and has captured the attention of various growers since its inception.
Huitlacoche is also gathering national attention in its main homeland of Mexico. News reports from the summer of 2015 in Mexico are stating that a new technique to more efficiently grow huitlacoche is gaining popularity. In San Felix Hidalgo, Atlixco, Mexico, local producer, Leobardo, is injecting Ustilago maydis spores into the silk of the corn to produce huitlacoche. Regular corn was losing value and a shift to a more prosperous product was essential for growth in their current economy.
This new technique was efficient and revolutionary enough to get Sagarpa and la Financiera Nacional de Desarrollo Agropecuario, Rural, Forestal y Pesquero involved. They created a plan of action dubbed, “Plan Regional de Fomento al Huitlacoche”, in which they would help local producers obtain the infrastructure necessary to follow with the production, industrialization, and commercialization of huitlacoche. With this added aid, local producers are now motivated to not only transform their farms, but also commit to a future in huitlacoche production.
Huitlacoche is potentially a highly profitable crop. It sells at a price much higher than regular corn and has the potential to be a local healthy, organic, niche-market product. Local restaurants in the area already have the dish in their menu, under conventional farming production, indicating that the product has a high demand. An interest in producing more conventional inoculation techniques for huitlacoche production is therefore still in high demand.