Sunday, October 12, 2008

F1 Snapdragon

What’s blooming in the area: Tea and miniature roses, gladiola, some kind of yucca, datura, Heavenly Blue morning glory, silver lace vine, mullein, white sweet clover, yellow evening primrose, alfilerillo, lamb’s quarter, chamisa, broom senecio, snakeweed peaked, wild lettuce, hawkweed, áñil del muerto, Hopi tea, gumweed, heath and purple asters, native sunflowers peaked; cottonwoods turning yellow by the river.
What’s blooming in my garden: Russian sage, catmint, golden spur columbine, large-leaf soapwort, California poppy, hollyhock, winecup, Jupiter’s beard, nasturtium, chocolate flower, fern-leaf yarrow, blanket flower, black-eyed Susan, Mexican hat, chrysanthemum, Sensation and yellow cosmos, perky Sue, African marigolds, Maximilian sunflowers peaked, zinnia; snowball leaves turning red, rose of Sharon leaves turning yellow.
Bedding plants: Snapdragon almost gone, sweet alyssum, moss rose, French marigold, gazania.
Inside: Aptenia, zonal geranium, bougainvillea
Animal sightings: Flock of small green birds in Maximilian sunflowers last Sunday; insects disappearing.
Weather: Yesterday’s rain was more welcome than the winds; frost on the car windows Thursday morning; 10:54 hours of daylight today.
Weekly update: Garden writers warn you: if F1 hybrids go to seed, they don’t come true. I have a yellow snapdragon growing amongst my pink and rose hollyhocks to prove it. Not just yellow. The buds are magenta, the aging flowers bronzed peach. Almost anytime I see it, the short, bushy plant has competing colors.
Two years ago I planted six pink Sonnet, six pink Rocket, and six red Rocket plants 15 to 20 feet downwind from where this yellow wonder appeared a year ago near the base of a hollyhock that apparently protected the tender perennial during the winter. I don’t know which plant, or plant combination, sired the fledgling, but the likely parents were all F1's.
We’ve known the habits of hybrids since Gregor Mendel described the dynamics of variation in 1866: that for every trait, nature begins with two alleles, one dominant and one recessive, and they always appear in a ratio of 1 pure dominant, 1 pure recessive, and 2 mixed. Seedsmen use F1 to refer to crosses between lines that have been purified through six generations to ensure all the alleles for a given trait are the same, and the resulting hybrid is predictable. However, as soon as the protected offspring is fertilized it reverts to the 1A:2Aa:1a pattern.
What’s surprising is that it took so long, nearly a hundred years, for seedsmen to exploit that knowledge for Antirrhinum majus. Rocket was the first popular F1 introduced by Harris Seed in 1960 when it won six All-American selection awards. Burpee had the first F1 award winner in 1957 with its rose-colored Vanguard. Sakata’s Sonnet became available through Stokes in 1988.
At first, those like Mendel who tried to replicate Darwin’s findings worked with economically important plants that were easy to manipulate, like corn, or with the anomalies he identified, like snapdragons. At Michigan Agricultural College, William Beal described methods any farmer could use to produce hybrids in 1876. He alternated rows of two common corn varieties, southern dent and northern flint; then removed the tassels from one group, to ensure all the seed would have the same male-female cross. The resulting crop produced 21 to 51 percent more corn. My home county production in 1874 was nearly 39 bushels an acre.
By 1900, a number had observed patterns like Beal’s and were ready when Hugo De Vries publicized the monk’s work in Germany. A few months later, William Bateson translated his article into English for the Royal Horticultural Society. Both men addressed an international breeders conference in New York in 1902.
Botanists pursued the mechanisms for selection, the chromosome and gene. Those who wanted to know why a red and a white snapdragon always produced pink ones and why the dominant to recessive color hierarchy dictates magenta over yellow, crimson over bronze, and bronze over yellowish-bronze learned combinations of genes could control a trait. Erwin Baur was using Antirrhinum in 1907 when he discovered mutations could be unstable. Hans Sommer’s team established snapdragon genes could change places to create these unexpected variations in 1985.
Seedsmen preferred the simple and predictable, and continued to refine pure lines into selections. Sutton offered 67 snapdragon varieties in England in 1926. Thompson and Morgan listed 82 in 1955. Two were advertised as reselected, but none were described as hybrids.
Farmers stayed loyal to Beal’s methods long after Donald Jones produced inexpensive hybrid seed in 1918, because his double-crossed corn required maintaining four potentially patentable pure lines to produce the immediate parents of seed that couldn’t be saved. Economically pressed farmers didn’t want to become dependent on seed salesmen, especially when many of the early releases didn’t adapt to local conditions. It wasn’t until the reorganization of agriculture in the 1930's that hybrids were accepted. This year Michigan is expected to harvest 140 bushels an acre, more than three and a half times the 1874 yield.
By then, the demand for ornamental seeds was depressed and flower seed breeders were more interested in exploring the possibilities of chemically altering the fertilization process to keep all the genes from both parents. Instead of four possible outcomes for any given mating, there were sixteen. In 1938 Bernard Nebel and Mabel Ruttle established colchicine as the best catalyst; in 1942 they published research on sterility in tetrapolid snapdragons. David Burpee introduced his first variety in 1946; Thompson and Morgan offered three in 1955.
The market for ornamental seed in the lean years of the 1930's and 1940's was florists. It was the expansion of suburbs after the war that created new demand for cut flowers on plants that homeowners could grow. Fred Stratt turned to F1 crosses, but his employer, Harris Seed, couldn’t afford the labor-intensive fertilization control required to mass produce Rocket seed. They teamed up with PanAmerican who had begun producing its seed in low-cost Costa Rica in 1946.
And so finally, decades after Mendel and Beal and Jones had worked out the theory, method and incentives for producing a robust F1 hybrid, I can buy good snapdragons. But when I look at what happens if one actually thrives and goes native, I’m still left with the question every farmer has ever asked when faced with a piebald: "Whoever was your daddy?"
Desai, Babasaheb B. Seeds Handbook: Biology, Production, Processing, and Storage, 2004, describes color hierarchy for breeders.
Everts, L. H. County history for 1877 includes data from 1874 census on crop yields; errors in reporting are possible.Fitzgerald, Deborah. The Business of Breeding, 1990, traces the resistance to hybrids.Michigan Corn Growers Association. "Michigan Corn Crop Outlook is Favorable," 3 October 2008 press release.Paul, Diane B. and Barbara A. Kimmelman. "Mendel in America: Theory and Practice, 1900-1919," in Ronald Rainger, Keith R. Benson and Jane Maienschein, The American Development of Biology, 1988.Rice, Graham. "Antirrhinums (Snapdragons)," Garden Answers, April 1999, has information on Sutton’s.Zhang, Dongfen, Qiuying Yang, Weidong Bao, Yu Zhang, Bin Han, Yongbiao Xue, and Zhukuan Cheng. "Molecular Cytogenetic Characterization of the Antirrhinum majus Genome," Genetics 169: 325–335:2005, reviews history of genetic research with snapdragons.
Photograph: Two-year old second generation F1 snapdragon between showers, 11 October 2008.

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