Hybridizing | ongardening.com

Hybridizing plants is an easy process: bees do it! They’re usually pollinating plants of the same species, but occasionally, they move a plant’s pollen to a different, compatible species and, without intention, begin the process of natural hybridization.

Human hybridizers, by contrast, have a plan: to improve specific plants. Pursuing this goal requires more than accident. Legendary hybridizer and sometime romantic botanist Luther Burbank said, “The secret of improved plant breeding, apart from scientific knowledge, is love.”

Another important secret, according to contemporary hybridizer, Karen Zimmerman, is fun! She strongly recommends and enjoys hybridizing aloes and growing plants from seed.

Zimmerman is the Succulent Propagator for the Huntington Library, Art Galleries andBotanical Gardens, in San Marino, California. The Huntington’s Desert Garden is one of the largest and oldest assemblages of cacti and other succulents in the world, so her work includes a generous measure of fun.

Speaking to the Monterey Bay Area Cactus & Succulent Society, Zimmerman focused on hybridizing aloes, a genus of succulent plants that includes some 450 species.These include the common Aloe vera, which has a variety of medicinal uses, including soothing sunburns, but a wide range of other forms exist within the genus.

As a hybridizer, Zimmerman studies the several kinds of aloes and explores the potentials of combining features of different kinds to produce hybrids with desirable characteristics. She described several categories of aloes:

Size & Form: miniatures, shrubs, trees, and creepers
Unusual Leaf Arrangements: fan, spiral rosette
Teeth, Prickles, “Warts” or Bumps
Colors: white, green, red, black, various patterns

She recognized several prominent hybridizers of aloes, including Kelly Griffin ofAltman Plants, and Brian Kemble of The Ruth Bancroft Garden & Nursery. Hybridizing can build upon the products of other hybridizers, or work primarily with natural species. Hybridizers typically welcome efforts to add to their successes by crossing their hybrids with other plants. This approach is not so much plagiarism as respect.

Generally, hybridizing can seek improvements in plants for landscape appeal, flowering, vigor, pest or disease resistance, or other characteristics. Zimmerman emphasizes what she terms “fantasy aloes,” which have unusual colors, patterns, or spinose teeth on the leaf margins. She has introduced several hybrid aloes with names that suggest fantasies, e.g., ‘Dragon’,‘Gargoyle’, ‘Wily Coyote’, and ‘Chameleon’.

The process begins with transferring pollen from one plant to another. Zimmerman uses various tools for this task, and currently favors her fingers, tweezers, and dentistry tools.

The nextstep is to collect the resultant seeds, which are small and easily lost.Zimmerman recommends mesh drawstring gift bags, which are inexpensive and effective in catching seeds.

She plants the seeds with labels indicating the “pollen parent” and “seed parent,” plus date and other information of interest. Her planting mix is 80% pumice and 20%forest humus, with the seeds covered with grit. The seeds need to be kept in warm, moist conditions, which can be provided with a closed plastic bag in indirect light.

Aloes, which are monocots, germinate and produce one leaf from the seed in about two weeks. As the plants develop, the hybridizing process consists of editing: the cross between two plants produces numerous seedlings, some of which hopefully will exhibit the desirable traits the hybridizer intended, and others (perhaps all!)will be—as Zimmerman describes them— less interesting, boring, or even ugly.

The seedlings will take various amounts of time to show their mature form. Zimmerman compares them to human teenagers, who reveal their “true selves” at various ages. Some very young seedlings will be unique in interesting ways, while others might be late bloomers.

Editing the seedlings can be the hybridizer’s most important function. It involves choosing those that are worthy of continued development and those that are discarded to make room on the nursery bench.

The hybridizer thinks of appropriate names for the successes and eventually introduces them to commercial distribution. That process uses tissue culture(cloning) to propagate enough cultivars to meet market demand. Seed propagation doesn’t work because growing hybrids from seed yields unpredictable results.

Throughout her talk, “Aloes on My Mind,” Zimmerman demonstrated her continuing enthusiasm for hybridizing aloes, and revealed that, “The real fun is imaging what’s next!”

The succulent gardeners in her audience recognized that hybridizing plants is easy and an enjoyable aspect of gardening that they might just try themselves. One of them could produce next season’s most exciting hybrid aloe.

The future of hybridizing has already begun; we soon will see the transformation of Nature’s ancient methods, and the rapid introduction of amazing new cultivars.

The basic method for creating new varieties of ornamental and edible plants has been practiced by bees and other pollinators for a very, very long time. This approach, called crossbreeding, involves sexual propagation: fertilizing one plant with the pollen of another plant produces seeds that carry the traits of the two plants. When the seeds germinate, the next generation of plants shows combinations of the traits of their two parents.

Plant hybridization has advanced greatly since 1900, when modern genetics began on the basis of Gregor Mendel’s work, but still follows the natural process. Rather than combining plants randomly, like bees, human hybridizers try to combine the traits of two plants to produce hybrid plants that are better than either parent. With ornamental plants, for example, a hybrid’s blossoms might be larger, more attractively colored, more numerous, etc.

This process requires time for seeds to germinate, develop into new plants and reproduce to produce a marketable number of hybrids. Often the majority—or all— of the seedlings do not equal the hybridizer’s vision, and are discarded, so that the process begins again.

Genetic researchers recently have developed ways to hybridize plants faster and with greater control than has been possible with the bees’ method. The new approach uses “genetic marking,” a technique to identify the gene or gene combination that results in a desirable trait in the plant.

The modern hybridizer then crossbreeds plants with desirable traits, grows the resulting seeds, and analyzes the genes in the hybrid to determine if it exhibits the desired trait(s).

A second, related development is the seed chipper, a device that determines if seeds will produce plants with desired traits. This process of “breeding without breeding” greatly speeds conventional hybridization.

Monsanto Company is pioneering the new methods for accelerating and controlling hybridization. These new methods do not involve transferring the genes from one species into another species so they differ from Monsanto’s highly controversial work in genetic engineering.

The new methods have been applied to vegetables: tomatoes, lettuce, peppers, broccoli and onions. Some “super produce” has already appeared in selected markets.

Given the progress of technology, we will see “super ornamentals” in the near future. Today, we can only speculate about how they will look and how they will grow.

New methods, new plants, and new questions!

Basic “how-to” descriptions of the traditional methods for hybridizing plants are readily available. Search the Internet for “hybridizing plants” or a similar phrase. The methods are really the same for all kinds of plants, but find information for specific plants by searching for “hybridizing roses,” inserting the plant name of interest.

For example, the article, “Try Your Hand at Hybridizing Irises,” appeared in Fine Gardening magazine, and was published originally in William Shear’s book The Gardener’s Iris Book (Taunton Press, 2002).

For more information on the new technology for hybridizing, see Ben Paynter’s article, “Monsanto Is Going Organic in a Quest for the Perfect Veggie,” in Wired Magazine, or “Monsanto’s Technology Platform in Wheat,” on the website of Monsanto Company. More detailed information on this technology is available on the Internet. Search Wikipedia or the Internet generally for “marker-assisted selection” or “molecular breeding.”

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Tag Archives: Hybridizing

Hybridizing Aloes

The Future of Hybridizing