LANDRACE, OPEN-POLLINATED, HYBRID, AND HEIRLOOM
A history and some differences
Plant cultivation – whether in the garden or on farms – goes back tens of thousands of years, exactly how far back is still a serious question for archaeologists, historians, and even linguists.
Within that, plant “breeding” specifically, goes back just a few millennia. The earliest vegetables, fruits, and grains were variable in their genetic makeup and it was easy to improve a type simply by selecting, via discriminating harvest, for attributes such as productivity and, just as importantly, adaptation to environmental factors. Few other attributes were (and are) considered, however, and in many cases, the variability in other expressed characteristics remained high. These still-variable clusters of related plants, from interbreeding varieties or even species, are now called “landraces.” It’s a semi-technical term and not a true botanical term.
Landraces, even those maintained today, display a much greater genetic diversity than modern open-pollinated varieties and considerably more than cultivars/varieties subjected to formal breeding practices. It’s this genetic variability that gives them the flexibility to survive a range of environmental pressures such as diseases, drought, and other threats, hence preventing loss of an entire crop when some pressure becomes intolerable. It’s this genetic variability that allows them to survive changeable environments.
Most seed companies, even the majority of the smaller specialists, don't sell landraces because customers generally want to know what they're going to get and they want consistency. Landrace vegetables (and some fruits) are usually products of a large communal trade scheme, typically coming out of low-input farming systems.
Open pollinated varieties, including heirlooms, may also be genetically diverse, but they are seldom as diverse as landraces. O.P. (open-pollinated), including “heirloom,” varieties can be highly inbred, often having originated from a single seed from a single plant.
Unlike familiar heirlooms, a landrace that is adapted to a specific bioregion will probably also thrive just as well outside of that region. Because a landrace is such a diverse genetic population, it is most likely that at least some of the individuals will thrive in a PNW garden regardless of where it originated.
More refined selection, including several additional selection methods developed later, focused on several other attributes. And now-familiar hybridization techniques came much, much later.
F1 HYBRIDS AND O.P.s
Although commonly written “F-1 Hybrid,” the two-character part is technically written as F1, with the 1 as subscript.
“F1” stands for “first filial generation,” or, plainly, what comes from the combination of genes from two distinct parents (the “crossing”). Not important here but interesting: if that first generation ever produces a second generation, those are F2 and a third generation would be F3 and so on.
The word “hybrid” was initially used by biologists for those creatures that came from the crossing of two distinct species. The longer, more accurate term for this is “interspecific hybrid.” Many vegetables are exactly this, happening either naturally or at the hands of early human civilizations.
The best-known examples of interspecific hybridization among the vegetable kingdom include watermelons, broccolini, rutabagas, some kales, and even the best known of complex hybrids, potatoes and tomatoes (the last two almost always listed as a species because of their gene numbers which make them reproductive even when isolated from their parents). Most of these are ancient hybrids, going back hundreds of years. There was even a “rabbage” (an intergeneric hybrid of radish [genus Raphanus]crossed with cabbage [genus Brassica) at one time; it didn’t sell.
Maybe the old champion of interspecific — and even intergeneric — hybridization is common bread wheat (now Triticum aestivum). Around 30,000 years ago, a wild wheat (Triticum monococcum) hybridized with a species of goat grass (Aegilops speltoides) to generate a primitive wheat called emmer. Then about 9,000 years ago, this new emmer wheat crossed with another wild goat grass (Aegilops tauschii). All of this gene exchange, by the way, created a plant with a multitude of chromosome sets, so many so that it was able to reproduce itself as itself; in other words, it had become its own species.
Many fruits, too, are hybrids. A few examples: peanuts, apples, strawberries, blueberries, bananas, and almost all our citrus (yuzu, grapefruits, tangerines, lemons, and many, many more). These hybrids can only be propagated vegetatively, typically by cuttings, divisions, or grafting onto a specified rootstock. [Yes, growing citrus from seed is fun for children; not, however, a recommended way of getting good oranges.]
But today, the word “hybrid,” when it comes to flowers and vegetables as far as gardeners are concerned, has a narrower definition. The contemporary word here is more a legal term, one of commerce and detailed documentation. An “F1 hybrid” is made by crossing two different parent varieties OF THE SAME SPECIES (for example, tomato x tomato). To advertise and sell a vegetable variety as an F1 hybrid, the parents must be known and named, and the pollination process controlled. The offspring of such pollination crossing produce a new, uniform seed variety with specific characteristics from both parents. For example, breeders may choose to cross two tomato parents to make an F1 hybrid that exhibits the known early maturity of one parent with a known specific disease resistance of the other.
Essentially, breeders are looking for recessive genes, the genes that aren’t abundant in the general population of the plant but are worthwhile genes from a human perspective. In a general population, dominant genes are the ones that show their faces.
The unique characteristics of an F1 hybrid plant are very uniform only in the first generation of seed, so seed saved from F1 plants to produce an F2 generation will not “come true” if replanted. A remixing and regression of genetics makes for undependable and usually not-so-desirable expressed characteristics; the regression refers to that takeover by dominant genes. This, along with the high price of F1 seeds, seems to be what bothers home garden seed savers the most. To produce consistent F1 hybrids, the original cross (exact same parents) must be repeated each season.
(HOT NEWS: it has been shown with some so-called F1 hybrid vegetables that, when they have been allowed to set seed and volunteer in the garden, F2 plants are near identical to their parents! The question is not “How did it do that?” but rather “Is it really an F1?” in the seed packet)
Most new vegetable varieties are F1 hybrids.
“O. P.” is the commonly understood anagram for “open pollinated.” “OP” seeds are a result of either natural pollination processes (the birds and the bees and the butterflies and a gazillion others). Or from human selection from a varied population for specific traits, which are then reselected in every subsequent crop of flower or vegetable.
These traits are relatively fixed within a range of variability. Ordinarily, open-pollinated seeds are not referred to as cultivars (nor varieties) as there is still some variability. The word “strain” (or “grex”), instead, fits here better. Marketers often use the term “Series” for strains that are usually sorted out by color and the colors sold separately (although a mix of the colors within a Series is commonly available and sold as, of course, “Mixed Colors”).
Open-pollinated vegetable varieties reproduce themselves in one of two ways:
cross-pollination between two plants (via wind, insects, or water) or
self-pollination between male and female flower parts contained within the same flower or among separate flowers on the same plant.
So long as plants of an OP variety are kept isolated from different plants with which they can cross (hybridize), they will produce seed that will “come true to type” or, as amateur gardeners like to say, “true from seed.” In other words, the plants in the following generation will resemble the parent plants — of sorts, mostly, kind of, good enough.
“HEIRLOOMS”
Heirlooms are the more contemporary successors to landraces but the differences between “heirlooms” and landraces are not always clear.
Interestingly, heirlooms all started off as landraces. Over time, the landrace’s genetic diversity became whittled down further and further until all that remained was a somewhat true-breeding heirloom variety (strain?). Heirlooms have been maintained more fastidiously and hence are genetically more stable overall, genetically less diverse, and with more uniform and distinctly expressed characteristics in each generation. Heirlooms will more-or-less “breed true;” at least for a time.
There is a good deal of romance surrounding heirloom vegetables, usually more than is deserved. I don’t want to totally dismiss the concept of “heirlooms” but I think the perception behind this ever-growing popular trend needs to be addressed. This is a complex subject, to say the least, so I need to back-up with some real basics with some definitions.
First, the “selection” process: it’s the way humans began improving plants to suit human needs from before written history. It’s a simple process — one merely selects seeds from the best plant, or plants, among many. “Best” could relate to any number of features: largest fruit, biggest fruit, fastest growth, specific disease resistance, dry-soil tolerance, harvestability, and even something as minimally essential as edibility.
The selected seeds are then sown, at the appropriate time, for next season’s harvest. And from among those, seeds are selected again, from the best. Each succeeding year, the process leads to a better harvested product.
Originally, the birds and the bees and the butterflies, etc. did a particularly good job mixing up genetics to create the varied expressions of characteristics — the diversity that Mother Nature loves so much — from which humans could choose. Humans over time became more adept at the process, learning to control where the pollinators went and where they did not. This is the core of the human-intervened open-pollination process. Today’s amateur seed savers rely on this more controlled process.
Once humans get their hands into the flowers and do the job the pollinators did — transferring pollen from one flower to another — the process goes from being simple “selection” to being what we call “hybridizing.”
All heirloom varieties are open pollinated. But not all open-pollinated varieties can be considered heirlooms. The definition of “heirloom” hasn’t been universally accepted yet but, generally, it means (1) a variety (cultivar or strain), that is at least 40 to 50 years old and upwards of 150 years (or, commonly used, “several generations”), and (2) that which has been preserved and kept true in a particular region (it has a provenance, of sorts). The definition once included: (3) those that are available only through small specialists, those who sell primarily or exclusively these old-fashioned seeds; but at the moment, there are many large-scale seed retailers who are cashing in on the heirloom movement.
For example, if a particular kind of open-pollinated pepper has been grown in some part of Vermont or Maine for 5 or 6 generations and seed has been prudently selected and saved by local growers and gardeners, it would be considered an heirloom variety.
The term “Heritage” is pretty much a synonym for “heirloom” but in a refined sense it is associated more with a cultural or historical legacy than with a plant’s genetics.
Heirloom varieties were developed when seed companies were regional and were promoting varieties for specific locations. THAT is a good thing for gardeners; not so much for commercial seed companies who rely on the broader demographics of a national market (= more customers = more money).
Seed saving organizations, some specialty seed companies, and home gardeners have been the agents that have kept heirloom varieties in existence over time.
The heirloom vegetables that have been saved have some real virtues. The classic examples are heirloom tomatoes that, as regarded by some, often have superior flavor (albeit subjective), color, or texture for home garden situations. Commercial interests, however, bemoaned the fact that almost all heirlooms lack the holding ability, disease resistance or early maturity, shippability, etc., that would make them commercially viable. [I might post a hybrid to O.P. comparison article soon.]
The most essential piece of the heirloom’s definition is the “regionality,” the provenance, the local history. Heirlooms have been selected to do well in a specific area. That’s that “selection” process as already explained. A strain of tomato that has been selected for the environment and issues of the Brandywine Valley (Pennsylvania into Delaware), for instance, does very poorly in the Salinas Valley of California.
When is an heirloom no longer an heirloom? As soon as it takes on new genetics, especially those that make it more adaptable to another region. When seed-savers collect their own seed — from plants that show desirable adaptations to the grower’s environment and issues — they have created a strain that is no longer exactly the “heirloom” they bought in the original seed packet. Over just a few years, a gardener may have ‘Joe Schmoe’s South Pasadena’* strain of tomato (or pepper or pumpkin or whatever). Seed-saving can be more than you expected. In fact, even in the Brandywine Valley, what is today grown as ‘Brandywine’ tomato is genetically different from what was grown as such some 50 years ago; the selection processes each year has perpetuated those tomato genetics that have withstood the environmental conditions of that year -- and those conditions have changed.
[* There’s now an actual ‘California Brandywine’ tomato that has been selected from the original ‘Brandywine’, over time, in Southern California. “Heirloom?”]
I like heirloom plants. I’m not so captivated by the romance of these old-timers as everyone else seems to be, though. What is most intriguing is their adaptability, their regionality. Among my three important mantras of general gardening, is “Right Place, Right Plant.” I encourage all gardeners to find the heirlooms of their region rather than fall in love with just the romance of these old-timers. THAT is “right place, right plant.”
A plant’s genetics will change, whether with subtle selection or with hybridization. As long as it’s for the good of the variety(ies) and as long as it doesn’t become an exclusive “property” of some entity, then we have progress. Don’t get me started on GE’s/GMO’s.
© Copyright Joe Seals, 2025