Editor’s Note: Last week’s column talked about saving heirloom seeds that produce plants that resemble their parents. This week’s column explores creating plants with new traits or combining desired traits of different plants by managing flowers and collecting the seeds they set.
Having written a book on saving seeds of heirloom vegetables, I was immediately drawn to an intriguing new book on breeding new plant varieties by a young gardener named Joseph Tychonievich. From the first pages of Plant Breeding for the Home Gardener, Mr. Tychonievich (who is speaking this Saturday at the Berkshire Botanical Garden) openly shares his passion for all things horticultural, but with a decisively personal spin. While he loves the heirlooms and hybrids created by others, he is taken by the idea of creating plants that meet his personal needs, the gardener’s equivalent of a fashionista’s made-to-order or bespoke clothing, tailored to one’s personal needs and setting. His work on this front began in his youth, as he selected violas that would grow well in the northern area of Ohio where he grew up, and has grown into a passion for custom-made varieties of tomatoes and fragrant columbines (which immediately grabbed my attention).
But what is most exciting is that the author does his breeding work to create his own plant varieties not in a science lab but through techniques, some of them age-old, which can be replicated in our own backyards. And these techniques help us, whether we are saving heirloom variety seeds to plant again next year or creating a new cultivar to develop and share with friends. When working with an heirloom variety, we know the traits that we are hoping to preserve – a fragrant sweet pea, a double pink columbine flower, a purple-fruited tomato, a zucchini plant that is resistant to borers, or whatever else the cultivar is known for. And we preserve these qualities by making sure that these varieties are fertilized by their own kind – a ‘Lumina’ pumpkin should receive pollen from another ‘Lumina’ pumpkin to remain true. We often isolate these plants from other varieties in order to get the desired results and then collect the seeds, confident that if we protect them from unwanted cross pollination we will get the plants we desire.
But when taking on a breeding project, we first need to determine what we are looking for: disease resistance, the color or form of a flower, fragrance, or the taste of a plant’s leaves or fruits. Then, we need to manage the reproduction of these plants in such a way so as to increase our chances of getting our desired results. It is crucial to select varieties that have the traits we want, in hopes that they will cross and share these traits. This requires perseverance and patience, but provides us with a surprising amount of fun and a sense of play as well.
Tychonievich bred his own strain of violas by simply removing the ones that he did not like or that succumbed to summer heat too soon. Selection is one of the essential aspects of plant breeding. By determining which plants would be allowed to flower and to set seed, and by removing everything from the gene pool that did not match the traits he desired, Tychonievich essentially limits the gene pool to plants with the traits he wants. This is one approach to selection and breeding, and it can work well for out-crossing crops such as violas. Taking away undesirable plants means that the remaining plants will share their qualities with one another. Although recessive traits may still reside in their genes, this separation greatly increases the odds that desirable traits will move forward. Continuing this selection process over a few seasons promotes the stabilization of these traits within the plants in later generations, and thus a new variety is born.
With other plants, making such crosses can be a little more complex, but not beyond the abilities of a home gardener. In the case of plants that are primarily self-pollinating, tomatoes for example, to cross two varieties in the hopes of getting one that combines their traits involves removing the anthers of one flower (known as emasculating it, a term that makes men shudder) and pollinating it with the pollen of the other variety. The fruit that results from this process will resemble the fruit of the mother plant, but the seeds will inherit traits from both parents. This will be evident when those seeds are grown on and produce fruits and flowers of their own.
The same process of hand-pollinating can be done with plants that have both male and female flowers, such as squashes. In this case, the chosen sire pollinates a female flower and the fruit of that cross is marked for collection. This process does not happen overnight — seeds need to be grown on in order to evaluate the resulting plants — but it is not beyond the abilities of a home gardener. Reading this book inspired me to see the process as fun (and a chance to play god), as if one needed another reason to head into the garden each morning. As Tychonievich talks of the possibilities of yellow-foliaged, fragrant columbines with green flowers (columbines are great breeding subjects as the plants are known to be promiscuous – which seems like a kinder term when applied to these plants than when it was used by my grandmother about certain schoolgirls), one can imagine the pleasures of having something in the garden that is truly one’s own. For gardeners like me, who consider the plants in our gardens almost as our children, the idea of giving their breeding some thought sounds nothing short of miraculous and well worth the time to take on, or at the very least to dream about while reading this delightful book.
A gardener grows through observation, experimentation, and learning from the failures, triumphs, and hard work of oneself and others. In this sense, all gardeners are self-taught, while at the same time intrinsically connected to a tradition and a community that finds satisfaction through working the soil and sharing their experiences with one another. This column explores those relationships and how we learn about the world around us from plants and our fellow gardeners.