Sunday, May 10, 2015
Beans and Bees
Weather: Clouds Monday and Tuesday with some rain; strong winds Friday afternoon; below freezing this morning.
What’s blooming in the area: Spirea, snowball, silver lace vine, bearded iris, donkey spurge, blue flax; grape vines leafing.
Beyond the walls and fences: Alfilerillo, western stickseed, tansy mustard, hoary cress, oxalis, bindweed, goat’s beard, common and local dandelions.
In my yard: Grape hyacinth, vinca.
Bedding plants: Snapdragon, pansy.
What’s blooming inside: Zonal geraniums.
Animal sightings: Rabbit, small birds, ants.
Weekly update: Changes in plants arise from three processes: mutations like those that produced the major fruit trees, hybridization that produced corn, and Darwinian natural selection.
Mutations are rare. Carl Moh found it was possible to treat beans with gamma rays and have those with black skins produce ones with "a range of seed-coat colors from white, yellow, to grey brown." The process changes one gene from dominant to recessive and that change can be perpetuated.
Beans are structurally resistant to the hybridization. Flowers on common beans open briefly, the ones on limas not at all. They are self-fertilizing. When Paul Gepts tried to cross common beans from the Andes with those from Middle America the resulting seeds were sterile.
Human decisions altered the workings of natural selection. Working backwards, Gepts assumes natives planted the largest seeds from each year’s crops. By chance, they selected ones with particular types of proteins, and thus eliminated the protein diversity that had existed. The two characteristics happened to be genetically tied. Other forms of genetic diversity were unaffected.
Europeans introduced a more dramatic force for change when they brought honey bees. They force their way into flowers. Patricia Hoc’s team found, in Argentina today, wild and cultivated beans interbreed, and the domesticated ones triumph. Olivier Hardy’s team found Apis mellifera were the main pollinator of wild limas in Costa Rica.
In this country and elsewhere in the nineteenth century, breeders and farmers applied their time-proven techniques of selecting seeds without realizing they were working in an environment where the presence of bees made hybridization possible.
William Weaver has researched many of the heritage forms of lima and common beans. He found many variants within each type, some more stable than others. One called Linsenbohne was developed in Pennsylvania and taken to Switzerland in 1705 by the land agent who was helping a Mennonite group migrate. From there it spread through to alpine regions of Germany and northern Italy. In the Appalachians hills it’s still grown as Brown Lazy Wife.
King of the Garden is a lima introduced in 1885 by Frank S. Platt. It was being grown commercially in Carpinteria, California in 1904 in a field where it tended to rogue. Harry Fish noticed two sports, which he passed on to W. Atlee Burpee. With a little work to make them reproducible, they were introduced as Ford Hook and Burpee Improved in 1907.
As for the Hopi lima which I’ve been watching grow, Weaver thinks it’s a strain that "exhibits characteristics of crossing." He believes it was once plain orange, but now the seeds may be plain or speckled.
Honey bees are unnoticed agents of change everywhere fruit trees are planted.
Ernest, Emmalea and Gordon Johnson. "Fordhook Lima Bean Production," University of Delaware Cooperative Extension Weekly Crop Update, 11 March 2011.
Gepts, Paul. "Origin and Evolution of Cultivated Phaseolus Species," Advances in Legume Systemics 8:65-74:1966.
_____ and F. A. Bliss. "Phaseolin Variability among Wild and Cultivated Common Beans (Phaseolus vulgaris) from Colombia," Economic Botany 40:469-478:1986.
Hardy, O, S. Dubois, I. Zoro Bi, and J. P. Baudoin. "Gene Dispersal and Its Consequences on the Genetic Structure of Wild Populations of Lima Bean (Phaseolus lunatus) in Costa Rica, Plant Genetic Resource Newsletter 109:1-6:1997.
Hoc, Patricia S., Shirley M. Espert, Susana I. Drewes, and Alicia D. Burghardt. "Hybridization between Wild and Domesticated Types of Phaseolus vulgaris L. (Fabaceae) in Argentina," Genetic Resources and Crop Evolution 53:331-337:2006.
Kruhm, Adolph. "Highest Quality among Lima Beans," The Garden Magazine, April 1920.
Moh, C. C. "Mutation Breeding in Seed-coat Colors of Beans (Phaseolus vulgaris L.)," Euphytica February 20:119-125:1971.
Weaver, William Woys. Heirloom Vegetable Gardening, 1997.
Photographs: Native Seeds Search, Tucson, Hopi Gray lima bean, since post for 22 March 2015.
1. Day 74, 4 April 2015, open flower.
2. Day 85, 13 April 2015, open flower with buds in various stages.
3. Day 91, 19 April 2015, first seed pod, with dead flowers.
4. Day 97, 25 April 2015, first pod full sized with bulges for seeds.
5. Day 107, 5 May 2015, leaves turning yellow and falling.
6. Day 112, 10 May 2015, seed inside pod.