By Jill Henderson
Corn has been a staple in the human diet since the indigenous peoples of Mesoamerica began domesticating the wild grass for its sweet kernels some 10,000 years ago. Subsequent cultures encountering the crop quickly adopted its cultivation and use, including early Europeans exploring the New World. Fast-forward to modern times and corn is not only an integral part of American culture but an essential global commodity that steadily ranks among the top five agricultural products in the world.
Of course, corn isn’t grown just for food and feed anymore. Its use as an integral component of modern biofuels has driven cultivation into overdrive, with American farmers leading production worldwide. According to the USDA National Agricultural Statistics Service (NASS), U.S. farmers planted 91.7 million acres of corn in 2019, which is 3 percent more than in 2018 and significantly more than soybeans, the second-largest crop grown in the country. The USDA likens the total known acreage cultivated to corn as “69 million football fields” worth – the majority of which are seeded with genetically modified varieties. For organic, ecological and biodynamic farmers whose livelihoods depend on open-pollinated and organic feed and seed, these numbers are nothing less than a nightmare.
The Botany of Corn
The incredible diversity found in a simple grass, known to modern botanists as Zea mays, has been slowly and painstakingly developed over the last 10,000 years. Today there are five basic corn genotypes, which are determined by their heritable genes. These include dent, flour, sweet, flint and popcorn, which is essentially a specialized type of flint corn. Each of these types is prized for one of three primary characteristics of the kernel, including texture, sweetness and color.
Traditional breeding begins with one or more corn varieties and involves careful selection of desired traits such as plant form, kernel color, hardiness, time to maturity and disease and insect resistance, among others. Stable varietals are maintained using techniques such as hand-pollination, single variety planting, distance isolation, and physical barriers. Most varieties, both present and past, were created using intentional cross-breeding, while others were just the lucky results of accidental cross-pollination in the field that ultimately led to stable and useful varieties.
Corn is a monoecious plant, meaning it has both male and female flowers on every plant. The tassels are the male flowers, complete with elongated stamens and conspicuous pollen-producing anthers dangling from every thread. The silks that emerge from the ears are the external portion of the female flowers, which encompass the entire ear. Each ear shoot contains an inflorescence of flowers made up of many ovules from which elongated styles known as silks grow. Eventually, the silks protrude from the tip of the ear shoot and, when pollinated, mature into a single kernel of corn. Although multiple grains of pollen may land on a single strand of silk and germinate, only one will make it to the ovule in the race to pass on its genes to the following generation.
Because corn is a natural out-crosser, its pollen is designed to drift long distances, pollinating as many other corn plants as possible. This mechanism ensures a wide range of natural diversity within the gene pool and the survival of the species in the wild. This indiscriminate pollination, evident in all plants with wind-borne pollen, is why corn is sometimes referred to as a “promiscuous pollinator.” For farmers trying to grow corn of a single stable variety for seed or market, this kind of indiscriminate behavior in the field can wreak havoc on a season’s worth of work.
Same But Different
For ten thousand years, corn was bred using simple mechanical techniques to keep each unique variety pure and stable. Open-pollinated (OP) and heirloom seeds (which are just very old OP varieties) are the results of cross-pollination between genetically similar parents, whether in the field or through hand-pollination. OP seeds will come true to variety year after year if no cross-contamination from other varieties occurs during the growing season.
Hybrids, on the other hand, are a little more complicated. In the wild, a hybrid can occur naturally when two varieties cross-pollinate. But modern hybrids are the result of intentional cross-pollination between two highly inbred parents. In the trade, one inbred is used only for its pollen and is referred to as the “male” plant, while the other is used only for generating seed and is referred to as the “female” plant. Breeding hybrids like these involves meticulous pollination procedures every time the crop is grown for seed. Seed saved from first-generation hybrid crops will not come true to type ever again without matching the cross exactly – and this is often a trade secret of the breeder. Although some growers shun hybrids because their seed can’t be saved, hybrids are productive, disease resistant and can be produced organically.
Unlike hybridization, which is a relatively natural process of cross-pollination, genetically modified organisms (GMOs) are unarguably a wholly unnatural method of creating living organisms that have had the natural genetic structure of their DNA permanently and artificially altered. Most people aren’t aware that there are two classifications of GMOs. The first is referred to simply as a GMO and is designated as such by having an “artificially altered genome” or having been “altered in a way that does not occur naturally by mating or natural recombination.” The second has had a gene or DNA sequence from an entirely different species (including plant, animal, insect, bacteria, fungi, virus or human) inserted into a variety of different tissues within the host. These are commonly referred to as transgenic organisms, but many prefer the acronym GMTO (genetically modified transgenic organisms) to make their origins as clear as possible. Transgenic organisms are always GMOs but not all GMOs are transgenic.
Of course, GM and GMTO corn looks like any other corn on the outside and has much of the same physiological functions on the inside, which means it can and does pass its modified transgenes on to non-GMO corn through simple cross-pollination. In some cases, GMO crops are more promiscuous out-crossers than their non-GMO counterparts, which means they can be more aggressive pollinators in every respect.
Anyone who has ever grown certified organic seed stock knows that controlling the pollination process in corn is not only essential; it is a major undertaking. This is particularly true when growing OP corn in regions where the predominant varieties are GMOs. Many seed sellers admit that it is incredibly difficult to find uncontaminated seed, and many breeders have thrown in the towel, frustrated with their inability to create enough barriers and distance between the two to keep their corn pure.
In a 2013 article on the Seed Savers Exchange website, assistant curator Tor Janson and communications coordinator Steve Carlson discussed the ramifications of GMO intrusion in their trial of an heirloom blue corn. Their planting was at least a half mile from neighboring GMO cornfields and further buffered by extensive physical barriers that included elevation changes and woodlots – all traditional forms of isolation. Yet, when the corn ripened, they immediately spotted signs of contamination in the ripened kernels.
“From a population of over 200 plants, we found a few scattered off-type kernels on six different ears. This genetic contamination represents less than 0.1% of the population in this generation, but if those off-type kernels were planted in the next generation, those plants, with 50% GMO genetics, would introduce a far greater level of GMO contamination to the population.
“For the purposes of non-GMO food labeling, the level of contamination we experienced is acceptable. But for the purposes of saving seed, any GMO contamination is unacceptable because the contamination will increase exponentially in each successive generation.”
GMO patent-protected corn not only presents a legal threat to organic growers and seed breeders, but a historic and economic threat as well.
Breeding That Blocks GMOs
Ever since the advent of technology that allowed the creation of GMO crops without any legal protection or recourse to contamination, breeders have been searching for a way to thwart the cross-contamination of organic and OP corn. One plant breeder and researcher who has been at the forefront of this effort for more than 20 years is Dr. Frank Kutka. His extensive curriculum vitae includes a B.S. in biology from the University of Wisconsin College, an M.S. in animal ecology from Iowa State University and a Ph.D. in plant breeding from Cornell University. Dr. Kutka has held several prestigious positions during his career, including assistant director and SARE Coordinator for the Dakotas at North Dakota State University Dickinson Research Extension Center. He is currently a faculty member at the College of Menominee Nation Northeast Climate Adaptation Science Center, where he is developing a sustainable agriculture degree program and breeding pollen-blocking corn during the summer.
Dr. Kutka’s early work breeding pollen-blocking corn began in 2001 as a grad student at Cornell. His worked included an interesting genetic trait known as gametophytic cross incompatibility, which is naturally found in popcorn and teosinte (Zea mays parviglumis), an ancient relative of modern-day corn. First discovered in the early 1900s and used extensively to breed new popcorn varieties in the ’50s and white corn varieties in the ’70s, the trait known as Ga1S was known to inhibit the germination and growth rate of unrelated pollen in plants that carried the gene.
In 2004, after years of intensive breeding, Kutka introduced a variety of pollen-blocking corn that he named “Organic Ready” as a jab at Monsanto’s Roundup Ready brand. But Kutka was not the only breeder working with Ga1 pollen-blocking traits. Hoegemeyer Hybrids founder Dr. Tom Hoegemeyer, from the University of Nebraska, had already developed a line of hybrid pollen-blocking corn in the 1990s called PuraMaize. His hybrid was eventually patented and offered to the public through Iowa-based Blue River Organic Seed in 2011.
At the time, there was an effort to prevent Hoegemeyer from patenting a gametophytic cross incompatibility trait that had been known and freely used to breed corn since the 1900s. In the end, Hoegemeyer, Blue River, and their partners won the debate, claiming that their pollen-blocking line was not the result of just one genetic trait, but a gene-system consisting of multiple traits. PuraMaize is one of the most popular commercial choices for hybrid organic yellow corn on the market today.
Blue River boasts that while pollen from GMO, gene-edited and CRISPR corn might germinate on the silks of PuraMaize, if its own pollen is present it will grow faster and fertilize the ovule before the competition. The company touts that PuraMaize produces corn with GMO contamination levels that fall well below the European standard of one-tenth of one percent, while competing favorably with standard hybrid and GMO varieties for production and disease resistance. In terms of helping organic farmers produce a clean, marketable organic crop, there is no doubt that their system works.
The Next Row to Hoe
Over the last two decades, Kutka’s breeding projects have continued to focus on the Ga1S trait from South American popcorn as well as the Ga2S and Tcb1s traits from teosinte to create new pollen-blocking corn varieties that would be free for other breeders and farmers to use without the restraints and expense of patents. He wants farmers to know that many of these new varieties are referred to as “synthetics” by breeders. This, he says, simply refers to open-pollinated or hybrid varieties that have been intensively bred using multiple lines of pure inbred corn.
In a recent article he wrote for Broadcaster Press, Kutka said, “… many pollen blockers suffer from drawbacks – including complicated genetics – that have challenged breeding and marketability efforts.” Despite those challenges, he and many breeders have found much success over the years, creating both open-pollinated and hybrid varieties of popcorn, sweet corn and a wide array of specialty corn – all of which have pollen-blocking traits.
Although PuraMaize is still the most visible and widely used pollen-blocking “synthetic” on the market today, Kutka said that many varieties based on their genetics are available commercially. He also points out that a number of breeders are currently close to releasing several new Ga1 hybrids. These researchers include Walter Goldstein, founder of the Mandaamin Institute (mandaamin.org), whose mission is to “use ancient varieties of grain to enhance the quality and sustainability of modern corn crops,” and Dr. Major Goodman, of North Carolina State University, who is working on new sources of gametophytic incompatibility from the tropics. Kutka says he is currently adapting one of Goodman’s strains for the northern states and that he’s always happy to send a few seeds from his various breeding projects to breeders to use in their own projects. A few of his “populations” are currently in the commercial arena through Sand Hill Preservation Center in Iowa and Green Haven Open Pollinated Corn Group in New York. He said that his newest Ga1 pollen-blocking synthetic OP variety, Organic Rebellion, is currently available through Albert Lea Seed.
The next row that farmers hoe in terms of preventing GMO contamination in corn almost certainly must include the unique genetic gametophytic traits that allow corn to resist GMO pollination. These traits have been in existence longer than the advent of genetic modification, and yet here we are, still limited to only a few viable options for blocking GMO contamination. Like any good invention, it is the consumer that drives production. And nothing incentivizes innovation more generously than monetary support. The more farmers want and buy these seeds, the more breeders can focus on creating new and interesting varieties faster. The result for organic farmers is the ability to increase their bottom dollar while still retaining their integrity as eco-farmers.
Jill Henderson is an artist, author and organic gardener. She is editor of Show Me Oz (showmeoz.wordpress.com), a weekly blog featuring articles on gardening, seed saving, nature ecology, wild edible and medicinal plants and culinary herbs. She has written three books: The Healing Power of Kitchen Herbs, A Journey of Seasons: A Year in the Ozarks High Country and The Garden Seed Saving Guide.