Beltsville research center recognized for historical service

Associate Editor

BELTSVILLE, Md. (Nov. 10, 2015) — If you grow soybeans, you owe the agricultural research center here a debt — particularly if you’re growing them in Delmarva.
Were it not for the 41-year quest from 1918 to 1959 to isolate the pigment-containing protein called phytochrome, soybean production might still be an enterprise limited to the Midwest.
The American Chemical Society late last month honored that discovery, which occurred at the Beltsville Agriculture Research Center.
The society designated the achievement a National Historic Chemical Landmark, ranking it with many other important chemical discoveries such as the development of baking powder in Providence, R.I., in 1869 or the discovery and large-scale production of penicillin in the United States starting in 1939.
“It made a huge increase in where (soybeans) could be grown,” said Jim Bunce, a plant physiologist at the research center. “If you were to grow the wrong variety of soybean, it would never flower. You’d never get anything out of it. … They had real trouble growing soybeans in parts of the country.” 
Phytochrome enables plants to regulate growth and development through the detection of light and darkness, according to the chemical society. Some flowers, for instance, bloom based on changes to day length over the course of the growing season. This is known as photoperiodism.
Now, soybean varieties and their seeds are tied to different regions of the country by their photoperiod — short-day, long-day or day-neutral — which is based on their response to light in a given region or latitude. The improvement has led to an expansion of soy production in the United States and worldwide.
But soybeans weren’t the only agricultural product to benefit. Many popular seasonal flowers such as chrysanthemums and poinsettias were set up to grow throughout the year by manipulating their exposure to light and darkness. When scientists discovered in the 1930s that the amount of darkness plants experienced triggered photoperiodic responses, greenhouse growers changed the growing processes for some commercial plants and led to improvements, such as energy savings.
The search began at a Virginia USDA facility in 1918 with scientists trying to figure out why Maryland Mammoth tobacco plants failed to produce flowers at the end of summer like other varieties. They were also trying to determine why soybean plants matured at the same time even when farmers staggered their planting. This eventually led to a search for the chemical that caused photoperiodism, a search not without doubters. One critic called the search for phytochrome “a pigment of the imagination,” the chemical society said.
But the study of phytochrome and photoperiodism remains important, Bunce said, particularly in our warming world.
“With climate change, the same location is always going to have the same progression of day and night, but if we’re warmer we’re going to have to modify the soybeans we’re using so they will flower and yield at the same time,” he said.
Phytochrome also allows crops to detect weeds and other plants around them through the shade they create, among other things.
This can create reactions in the crop that are beneficial to agriculture and some that are not. Soybean plants, for instance, can grow taller when their phytochrome detects a nearby weed — a competitive response that can lead the crop to tip over and harm yields.
“It’s still a factor that needs to be involved in breeding programs,” Bunce said. “Breeders have to be very conscious of it.”