Crop bounty is well protected - Preserving Plants for the Future

Agricultural Research, June, 2003 by Sharon Durham

Wouldn't it be boring to have only one variety of watermelon or pepper? Fruit and vegetable growers strive to provide us with the produce we say we want. That's the whole idea behind marketing! But, fruit and vegetable growers must contend with changing environmental conditions, such as drought, flooding, viruses, and harmful pests to raise enough produce for the market.

In Griffin, Georgia, the Agricultural Research Service (ARS) houses the Plant Genetic Resources Conservation Unit, led by Gary Pederson. The unit, part of the National Plant Germplasm System (NPGS), can be viewed as a gold mine of plant species, with more than 82,000 plant samples, or accessions, held in the collection. (See related germplasm story on page 8.) The unit works in conjunction with the Southern Agricultural Experiment Stations, through the University of Georgia, to maintain the collection.

The unit serves as an invaluable resource for farmers facing tough or altered growing conditions. "Our unit sent out more than 100,000 plant germplasm (seeds or plant cuttings) samples in the last 3 years. Eighty-eight percent of the requests were from domestic growers; the rest were from foreign countries," says Pederson. By maintaining a repository of plant germplasm, it's possible for varieties used in the past in similar environmental conditions to be used now or in the future, as conditions dictate.

Growing conditions vary from year to year. Pests migrate from one location to another, and a season may be unusually wet or dry. Each plant variety thrives in specific, preferred conditions, and thanks to the efforts of a consortium of labs that make up the NPGS, they are available--and will remain so--to researchers, educators, and producers.

The keepers of plant germplasm have the very important task of safeguarding samples of all crops of agricultural importance. Through a national network, the samples are maintained as a means of preserving the productive capacity of agriculture and are provided to requesters around the world. But keeping the seeds and plant samples alive takes a bit of work.

Samples stored as seed are dried, cleaned, and packaged before being put in cold or freezer storage. According to seed storage manager Lee Ann Chalkley, seeds are stored in a freezer at about 0[degrees]F or a cold room at 40[degrees]F. Some seeds, like clover and sorghum, can last for 30 or 40 years in freezer storage. Each plant sample, or accession, is entered into the Germplasm Resources Information Network (GRIN) database, operated by the GRIN Database Management Unit, in Beltsville, Maryland. "Before the database was developed, all the records were kept by hand on card files," recalls Chalkley.

Consumers in the Driver's Seat

Forty years ago, a trip to the grocery store would have found a limited choice of produce to choose from compared to today's array. Your choice of peppers may have been limited to bell, pimento, or banana. But today, vegetable bins are graced with those and more: cayenne, jalapeno, habanero, and Scotch Bonnet, to name just a few. Today's consumer demands a greater variety of produce, and produce is now used for more than basic cooking needs. The snack industry has also begun to use fruits and vegetables in new ways. Vegetable chips such as sweetpotato are now available next to regular potato chips. These new uses require a different type of vegetable than the baking sweetpotato.

Have you ever wondered why the baked sweetpotato you remember and loved from a few years ago seems to taste a little different today? Well, that's because it may not be the exact same sweetpotato. Many factors may play into the change in a variety: consumer preferences, environmental conditions, or disease impact.

The Environment's Twists and Turns

Changes in growing conditions, like climate, rainfall, viruses, fungi, and diseases, are some of the challenges crops face. Different strains of the same plant species may tolerate high heat better than others. One strain may be resistant to a soil fungus present in a farmer's land, while the previous crop strain has succumbed. Matters are complicated when plants are grown in nonnative areas. For instance, Georgia and other southeastern states have been in a drought since 1998, which, thanks to heavy fall rains last year has been reversed.

Supermarkets in the United States have a wide range of fresh fruit and vegetable choices. But can you guess which ones are native to North America? Sweetpotato? Nope. Peanuts? Uh-uh. Watermelon? Try again. Actually, most agriculturally important crops in the United States came from other places on the globe. This means crops brought here to be grown had to adjust to the new growing environment.

Bright and Delicious Future

Maintaining the variety of plant genetic resources is a delicate task. Plant samples, especially cuttings, must be carefully tended to remain viable. When stocks are low, varieties must be propagated to increase the supply. In fact, some of the plant strains, like sorghum, have been in stock since the 1940s.