Zea mays (Nitrogen Fixing Corn)


Plant Family

Gramineae or Poaceae (Grass family)

Binomial Name

Zea mays

Common (Vernacular) Names

Nitrogen fixing corn (maize).


 

Plant Characteristics


Endemicity.  There are reportedly about 40 old landrace varieties of corn (maize), originating from Central America that are similar to the nitrogen fixing varieties described here.

Growth Habit.   These varieties of corn produce aerial prop roots or “fingers” on the lower joints of their stems.  These can exude a thick mucus-like gel that harbors beneficial symbiotic bacteria.  The bacteria fix atmospheric nitrogen into a chemical form that the plants can absorb and utilize. This process is called nitrogen fixation.  Gel production and the efficiency of nitrogen fixation is affected by environmental factors.  More gel is produced during cooler temperatures and periods of fog or high humidity.  During periods of high temperatures or drought the mucus may be absent.

Corn (maize) is the world’s most productive cereal crop.  Scientists have long sought varieties of corn that could fix nitrogen and are conducting research to determine if the traits for fixation can be bred into commercial cultivars.  If successful, these efforts could reduce the crop’s high demand for artificial fertilizers, which are energy intensive to produce, costly and contribute to water pollution and eutrophication.

 

Prop Roots of Nitrogen Fixing Corn

Immature Prop Roots of Nitrogen Fixing Corn
Growing at Discovery Harbour, Kau District, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Mucus on Aerial Prop Roots of Nitrogen Fixing Corn

Mucus Dripping From Aerial Prop Roots of Nitrogen Fixing Corn
Plant in Cultivation at Hilo, Hawai`i
Photo Credit: Caitlin Bolger

 

One giant variety of nitrogen fixing corn can grow much higher than modern corn cultivars.  The potted specimen in this photo taken on August  14, 2023 had reached a height of approximately five meters (15 feet) and was still growing, almost to the height of a several year old betel nut palm growing near it.  The corn was growing without fertilization in a soil mixture predominantly composed of volcanic cinders and soil discarded from our nursery operations.

Nitrogen Fixing Corn Plant Next to Betel Nut Palm

Nitrogen Fixing Corn Plant Next to Betel Nut Palm
Discovery Harbour, Kau District, Hawai`i Island
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Inflorescence.  The tassels, silk and ears of nitrogen fixing corn are similar to modern corn.  These photos were taken in August 2023 at our facility in Discovery Harbour, Kau District of Hawai`i island.

Male Inflorescence (Tassel) on Nitrogen Fixing Corn

Male Inflorescence (Tassel) on Nitrogen Fixing Corn
Discovery Harbour, Kau District, Hawai`i Island
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Styles (Silk) of Nitrogen Fixing Corn

Styles (Silk) of Nitrogen Fixing Corn
Discovery Harbour, Kau District, Hawai`i Island
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Female Inflorescence (Ear) of Nitrogen Fixing Corn

Female Inflorescence (Ear) of Nitrogen Fixing Corn
Discovery Harbour, Kau District, Hawai`i Island
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Seeds.  There are apparently many landraces (cultivars developed at specific localities by traditional farming methods) of nitrogen fixing corn originating from Mexico  Their seeds (kernels) come in a variety of sizes, shapes and colors, including white, red, pink, blue, gray and black.

 

Seeds of Mexican Landraces

Mexican landraces in our seed bank are shown in the photos below.  Most of these became available for sale from our ONLINE STORE by mid-May 2024.  There is high interest in these seeds and our inventories are low and fluctuate rapidly.

Nitrogen Fixing Corn Seeds, Yellow-Orange Landrace from Oaxaca, Mexico

Nitrogen Fixing Corn Seeds, Yellow-Orange Landrace from Oaxaca, Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Nitrogen Fixing Corn Seeds, Blue-Black Landrace from Oaxaca, Mexico

Nitrogen Fixing Corn Seeds, Blue-Black Landrace from Oaxaca, Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Nitrogen Fixing Corn Seeds, Giant White Landrace from Southern Mexico

Nitrogen Fixing Corn Seeds, Giant White Landrace from Southern Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Nitrogen Fixing Corn Seeds, White Landrace, Oaxaca, Mexico

Nitrogen Fixing Corn Seeds, White Landrace from Oaxaca, Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Additions in May 2024:

Nitrogen Fixing Corn Seeds, Blue-Black Landrace, Type 1, From La Fe, Mexico

Nitrogen Fixing Corn Seeds, Blue-Black Landrace, Type 1, From La Fe, Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Nitrogen Fixing Corn Seeds, Yellow-Orange Landrace from Chiapas, Mexico

Nitrogen Fixing Corn Seeds, Yellow-Orange Landrace from Chiapas, Mexico
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Research and Field Trials


Demand for our nitrogen fixing corn seeds and information about them has continued to grow.   The Mexican seeds are costly and their continuing availability is in doubt.  As we were attempting to fill international orders many restrictions and prohibitions on corn seeds originating from southern Mexico were encountered.  These stem from concerns about corn wilt and other diseases that may be present in Mexico but have not been reported in Hawai`i.    These circumstances caused us to consider finding another growing areas on Hawai`i island for seed production.

Growing Areas in Hawai`i

Discovery Harbour, Kaʻū District, Hawai`i Island

We originally did not intend to conduct research on nitrogen fixing varieties of corn and no space was available at our Discovery Harbour site for formal field trials. Germination testing of incoming seed lots from southern Mexico via was be carried out before offering them for use in educational programs and sale.   Several seedlings from the tests were planted at our Discovery Harbour facility for observations.  These produced cobs, some of them had viable seeds and these were offered for sale.

The photos below are of the first corn of this variety known to have been produced in Hawai`i.   At the time these plants bloomed and were pollinated no other corn was known to be growing in the area (Discovery Harbour, Hawai`i).  Only several plants were grown.  The small number of plants in the growing area probably resulted in low pollination and kernel formation. Seeds from these plants had a high germination rate and very limited quantities of them were available from our ONLINE STORE.  Some of the seeds were also grown on a research partner’s farm at Hilo, Hawai`i in 2023.

Cobs of Nitrogen Fixing Corn from Hawaii

First Cobs of Nitrogen Fixing Corn from Hawaii
Grown at Discovery Harbour, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-SA 4.0

In 2023 several additional seedlings from germination testing were planted in the spring at our facility in a large whiskey barrel container (volcanic soils in our area are probably too shallow to grow corn).  No fertilizers were added to the soil.  A seedling from the giant nitrogen fixing corn variety reached a height of more than 5 m (15 feet).  Shorter plants were also grown from the blue colored variety. No evidence of wilt disease was observed.

Aerial prop roots grew out of the lower stem joints on all of the plants and these usually exuded a mucus like material until the rains ended in the summer and the area entered into extreme drought.  While the soil in the growing container was kept watered during this time the mucus dried up and did not return.  Some of the tips of the projections turned downward and entered the soil forming roots on the ends.  These observations suggest that the plant’s ability to fix nitrogen could be impaired in the absence of rainfall.

Corn Plant with Rooted Aerial Props

Corn Plant with Rooted Aerial Props
Grown at Discovery Harbour, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per Use licensed per CC BY-NC 4.0

 

All of the plants produced small, deformed ears with few seeds.  The plants are apparently not pollinated, severely stressed by drought conditions and appeared to be dying at the time harvest.

Deformed and Immature Ears of Nitrogen Fixing Corn

Deformed Ears of Nitrogen Fixing Corn
Grown at Discovery Harbour, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC

 

 

Ocean View, Kau District, Hawai`i Island

In late 2023 we opened our Moana Experimental Farm at Ocean View in the Kau District of Hawai`i island for field trials of our other research crops.   The farm is at an elevation of 600 m (2000 ft) and in very windy area not suitable for for growing corn in the ground.  There is little soil at the site, which is on a recent lava flow and is mostly covered by crushed lava rock from grading and leveling activities.  However, it is far from other known corn growing areas so cross pollination with other corn varieties is unlikely.  In May of 2024 we planted seedlings of several landraces in large containers an attempt to produce more Hawaiian grown seed and to conduct a small study on the effects of fertilization.

For the study of fertilization seedlings of various corn landraces were planted in large pots of an unfertilized commercial topsoil mixture consisting of volcanic cinders, cinder fines and ash, and macadamia nut shells. Soil amendments of lime and a commercial innoculant were mixed into the top layer of the soil. The pots were enclosed by wire fencing material to help prevent the plants from being uprooted by the wind.  For each landrace, three seedlings were planted in each of two pots.  One pot was not fertilized, the other was fertilized at the time of planting (early May 2024) with a complete commercial fertilizer.  By late July there was a significant difference in the growth rates between the unfertilized and fertilized plants.  For all landraces the fertilized plants grew taller and had a more robust appearance.  Comparative photos of two landraces showing the difference in growth between the fertilized and unfertilized groups are shown below.

Photo of Oaxaca Yellow-Orange Corn Seedlings in Unfertilized Group

Oaxaca Yellow-Orange Corn Seedlings in Unfertilized Group
Growing at Moana Experimental Farm
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Photo of Oaxaca Yellow-Orange Corn Seedlings in Fertilized Group

Oaxaca Yellow-Orange Corn Seedlings in Fertilized Group
Growing at Moana Experimental Farm
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Oaxaca Blue Type 2 Corn Seedlings in Unfertilized Group

Oaxaca Blue Type 2 Corn Seedlings in Unfertilized Group
Growing at Moana Experimental Farm
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Photo of Fertilized Oxaca Blue Type 2 Seedings

Oaxaca Blue Type 2 Seedlings in Fertilized Group
Growing at Moana Experimental Farm
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

The strong trade winds, infrequent rains and highly previous planting soil at this site have placed the plants under severe stress.  Under these drying conditions none of the plants have produced mucus on their aerial roots and they are probably unable to fix their own nitrogen.  For optimal growth under these conditions they apparently require applications of fertilizer to provide nitrogen and other nutrients missing from the soil mixture in the pots.

The winds have toppled and repeatedly uprooted most of the plants.  As of this writing in mid-August 2024 most of the plants have bloomed and some are forming cobs.  So far it appears that most of the cobs will have few seeds, probably resulting from poor pollination conditions.  While seed production from this site may be low the seeds may be better adapted to drought conditions than those grown areas with more humid, wetter climates. We may offer some of these for sale from our online store.

None of the plants appeared to have wilt diseases or significant pest infestations.

On August 25, 2024 the winds from Hurricane Hone blew most of the corn plants down and out of their pots ending our field trials at this site.

 

Hilo, Hawai`i Island

In late spring of 2023 we provided seeds of the giant white and blue colored Mexican landraces, a large pink variety of the corn from Discovery Harbour to our student intern for a high school project.  These were grown in unfertilized soil by a volunteer farmer in Hilo, Hawai`i.  The farm is at an elevation of about 430 m (1400 ft).   Hilo probably receives more rainfall than any other city in the United States.

2023 Crop. Seeds of all varieties planted at the Hilo farm grew very well but the size of the planting was small because of the limited amounts of seed available..  The fingers maintained mucus coatings throughout the growing season. The ears were much fuller with seeds than those from the Discovery Harbour plants.

The color, shape and size of the ears and kernels was highly variable (see photo).  Seeds were collected separately from each ear and average seed weights were recorded after drying. Very limited quantities of these seeds was available from our ONLINE STORE and most of these have sold out. Photos of the seeds and weight data accompanied each seed lot listing in the store. The viability of the seeds was typically greater than 80%.

Image of Ears of Nitrogen Fixing Corn from Hilo, Hawai`i

Nitrogen Fixing Corn from Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

2024 Crop.  In the spring of 2023 we reviewed the growing area with the farmer to ensure that no nearby farms were planning to grow corn, which could cross pollinate with the nitrogen fixing corn.  Following this, seeds from the 2o23 Hilo crop were planted and were grown with open pollination.  Some of the corn was intercropped with moringa trees and the only fertilizers applied were animal manure from goats raised on the farm. No pesticides are used on the corn.  Corn produced from this farm is non-GMO and probably meets the requirements for organic production but it will not be certified.

By mid-July the first harvesting of this corn began and it will be continuing into September.  The ears are shucked and dried in a room on the farm with a dehumidifier.  After drying, the cobs are sorted into groups of similar form and color, and then the kernels are removed from the cobs, counted, weighed, bagged and transported to our seed bank in Discovery Harbour.  There the seeds are inspected, cleaned and further dried down to a level suitable for freezing. No pesticides are ever applied.  We freeze all of the seeds to control insect pests and ensure viability in long term storage.

Exciting News!   Our efforts to provide seeds for research, field trials and larger plantings have been severely constrained by the scarcity and price of seeds, and dependence on seeds from southern Mexico.  We will have at least 6,000 seeds from the 2024 Hilo Crop!  These have been sorted, processed, and tested confirming high germination rates.  Some of the seeds will be transferred to other seed banks for offsite storage and back up.  Most of our inventory is now available for purchase in our ONLINE STORE 

Photos of some of the various types of corn from the 2024 harvest at Hilo are below.  As more seeds become available, photos and additional data about them will be posted here. Descriptions with photos of the processed seeds in each lot are found in our ONLINE STORE  listings.

Image of Ear of Giant White Nitrogen Fixing Corn

Ear of Giant White Nitrogen Fixing Corn
Grown at Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Photo of cobs of red nitrogen fixing corn from Hilo

Red Nitrogen Fixing Corn from Hilo
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Image of Ears of Blue Black Nitrogen Fixing Corn

Blue Black Nitrogen Fixing Corn
Grown at Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Image of Ears of Giant Pink Nitrogen Fixing Corn

Multicolor Nitrogen Fixing Corn
Grown at Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

Image of Ears of Red Nitrogen Fixing Corn from Hilo

Giant Pink Nitrogen Fixing Corn
Grown at Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

Image of Ears of Multicolored Nitrogen Fixing Corn

Blue and White Nitrogen Fixing Corn
Grown at Hilo, Hawai`i
Photo © Edward Rau, Sustainable Bioresources, LLC
Use licensed per CC BY-NC 4.0

 

 

Plants and Seeds for Sale


Availability

Seeds of the nitrogen fixing corn varieties are in short supply and costly.  While the corn produced from them can eaten as corn-on-the-cob while still tender, or dried as a grain for making various dishes, our primary intentions in offering these seeds are for them to be used for educational purposes, research and production of more seed by others. We are hopeful that as production increases here in Hawai`i we will be able to offer larger amounts of lower priced seeds for other uses.

We offer limited quantities of seeds grown in Mexico of the blue-black, yellow-orange and white landraces, and a giant white variety.

In January 2024 we began sales of some seeds grown by our research partner’s farm in Hilo, Hawai`i.  Our inventory of these seeds was very small and most of the varieties sold out quickly.

In February and May 2024 we acquired additional lots of seeds from Mexico including landraces not previously offered.

In September 2024 we began sales of larger lots of seeds from the first 2024 harvest at the Hilo farm.

Our seed inventory changes frequently. We may limit purchases by individual customers and reserve some or all of our seed inventory for research purposes. The available corn seeds may be ordered through our ONLINE STORE.

 

Shipping

Domestic Shipments

These seeds can be shipped to all states after inspection by the Hawai`i Department of Agriculture.  There is no charge for this inspection.

International Shipping

Please contact us before placing orders for delivery outside the United States. Our online store may not accept entry of orders going to international destinations.

The regulations governing exports of corn seeds are complex and vary widely among the receiving countries.  Most countries now require inspection of the seeds and issuance of a Phytosanitary Certificate (PC) by the U.S. Department of Agriculture (USDA) for entry.  The fee charged by the USDA for these services is $61.00 or $106, depending on the total value of the shipment.

Our costs of processing, paperwork, special packaging, travel for inspections and shipping associated with international orders are often extremely high.  It has become necessary to establish minimum order sizes, and additional service charges for orders to countries requiring import permits, phytosanitary certificates, seed treatment or special inspections.  Please refer to our Terms of Use and Sale for additional information.

Phytosanitary Requirements. Because of concerns about the potential importation of seeds with pests or diseases affecting corn, many countries also have additional restrictions on importing seeds from areas where these pests or diseases may be present.  Mexico may be a prohibited origin because of the presence of corn diseases in the growing areas.  Plants grown here in Hawai`i  from seeds of Mexican origin have shown no evidence of wilt or other diseases.  This is based only on visual observations made without supporting laboratory analyses.

According to information received from the USDA the seeds from Mexico do not meet the entry requirements of the European Union. This is because the bacterium that causes a disease called Stewart’s vascular wilt and leaf blight of sweet corn and maize (Pantoea stewartii subs. stewartii), is endemic to the  parts of the USA and is now present in Mexico (Abidin et al. 2020), the origin of the seeds.

The seeds from Hawai`i may be subject to fewer or no restrictions because the wilt disease is not known to be present here (Pepper 1967) and we have shipped our Hawaiian grown seeds into the EU without problems.

Analytical test data is required for clearance and entry of the seeds into some countries regardless of the origin of the seeds.  For example, Japan’s regulations require testing to detect the nucleotide sequences found in the nucleic acids of the bacteria causing corn wilt and maize chloric mottle virus.  These testing services are not available here in Hawai`i so we cannot ship the seeds to Japan.

 

Seed Processing and Storage

We inspect all of these seeds when they are harvested or received from our suppliers.  They are then treated by drying and freezing to control insect pests and maintain viability in storage.  The seeds are shipped in plastic zip bags with silica gel packets to reduce moisture uptake by the seeds.

If you will not be planting the seeds on receipt we recommend keeping them in their original packing with the gel packet in an outer zip seal bag, glass jar or other impervious container. Then refrigerate or freeze them until they are planted.

Reporting Results

We view nitrogen fixing corn as a very promising but experimental crop.  There is very little information available on the performance of these potentially important corn varieties in growing areas outside Mexico.  Our experimental farm space for field trials is extremely limited.  So we primarily depend on our our seed customers to report on seed performance, and the pests and diseases of the plants grown from the seeds.  Please share this information with us.  We will publish useful information on this website for public access.

Additional Information

Because we are receiving a high volume of inquiries about this corn we may not be able to answer them in a timely manner.  For additional general information please refer to the references listed below.

 

References


Abidin, N., Ismail, S. I., Vadamalai, G., Yusof, M. T., Hakiman, M., Karam, D. S., Ismail-Suhaimy, N. W., Ibrahim, R., & Zulperi, D. (2020). Genetic diversity of Pantoea stewartii subspecies stewartii causing jackfruit-bronzing disease in Malaysia. PloS one, 15(6), e0234350. https://doi.org/10.1371/journal.pone.0234350

BBC Earth Lab.  2023. This Slime Could Change the World. https://www.youtube.com/watch?v=CFyd-kC6IUw

Daley J. 2018. This rare variety of corn has evolved a way to make it own nitrogen, which could revolutionize farming.  Smithsonian Magazine.  August 10, 2018. [Accessed November 3, 2022].

Glorioso Products (GP).  2021, 2023.  Personal communications.

Hamilton E. 2018. Corn that acquires its own nitrogen identified, reducing need for fertilizer.  University of Wisconsin Madison News.  August 7, 2018. [Accessed November 4, 2022].

Japan Plant Protection Website. 2023.  Plant Protection Law Enforcement Regulations. https://www.maff.go.jp/pps/j/law/houki/shorei/shorei_12_html_12.html [From translation by Hiroshi Katsumata, in Personal Communication of December 24, 2023].

Pepper, EH. 1967. Stewart’s bacterial wilt of corn. In: Monographs. American Phytopathology Society, (4) 36 pp.

Van Deynze A, Zamora P, Delaux P-M, Heitmann C, Jayaraman D, Rajasekar S, et al. 2018. Nitrogen fixation in a landrace of maize is supported by a mucilage-associated diazotrophic microbiota. PLoS Biol 16(8): e2006352. https://doi.org/10.1371/journal.pbio.2006352 [Accessed November 4, 2022].

Yong E. 2018. The Wonder Plant that Could Slash Fertilizer Use. In: The Atlantic, August 9, 2018. https://www.theatlantic.com/science/archive/2018/08/amaizeballs/567140/ [Accessed Septmenr 9, 2024].


Page last updated on September 9, 2024.

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