The release of new upland cotton germplasm should provide valuable sources of genes to enhance traits of economic importance to the cottonseed and textile industries. The lines originated as 58 randomly selected plants from crossing PD-3-14 germplasm, released by ARS in 1993, and Simian 2, developed by the People’s Republic of China’s Cotton Research Institute at the Chinese Academy of Agricultural Sciences in Anyang, Henan Province. They have been maintained under forced self-pollination to control genetic variance. The lines also have been evaluated for an array of agronomic and fiber traits. Compared with their parents, the 58 lines vary widely in lint yield, lint fraction, boll size, seed index, weight of lint per seed, fiber property strength, length distributions, fineness, short-fiber content, maturity, and immature fiber content. Encoded genes for these traits can be tagged with molecular markers for breeding, and functional genomic analysis can be used to discover new genes. A limited quantity of seed is available from ARS for distribution to cotton breeders and geneticists. Genetic material will be deposited in the National Plant Germplasm System, where it will be available for research, including development and commercial sale of new cultivars.

Coastal Plains Soil, Water, and Plant Research Center, Florence, SC
Lloyd O. May, (843) 669-5203, ext. 7255, cotton@florence.ars.usda.gov

A native bee that excels in pollinating blueberries is—surprisingly—befuddled by the task of pollinating a blueberry relative, the American cranberry. Osmia ribifloris, a medium-sized bee that sometimes has emerald-green highlights in its shiny, steel-blue body, is seemingly an ideal candidate for work in cranberry bogs. That’s because blueberries and cranberries—both native to the United States—are cousins. But ARS tests using O. ribifloris bees in screen cages placed over blooming cranberry plants in a commercial New Jersey bog showed that the native bee consistently lands in the wrong position on cranberry flowers. That means the bee isn’t able to use its legs to hit, or drum, the flowers’ pollen sacs. Normally, drumming would cause the sacs to release pollen that would then be trapped in the dense brush of short hairs on the female bee’s abdomen. Scientists have eliminated O. ribifloris from the list of potential cranberry pollinators and are focusing their efforts on two other promising candidates that they observed landing correctly on the blooms. Those bees are an O. ribifloris relative called Osmia atriventris and an energetic leaf-cutting bee called Megachile addenda. Cranberry growers funded the research through a cooperative research and development agreement. They are seeking new pollinators to help out Apis mellifera honey bees beleaguered by competition from aggressive Africanized honey bees or by attack by tracheal and varroa mites, small hive beetles, or microbes that cause chalkbrood, American foulbrood, and other diseases.

Bee Biology and Systematics Laboratory, Logan, UT
James H. Cane, (435) 797-3879, jcane@biology.usu.edu

Compounds called peptides that may play important roles in controlling feeding and reproduction have been detected in extracts from an important soybean pest. Soybean growers currently use resistant bean varieties and crop rotation to battle their greatest foe, the soybean cyst nematode. This microscopic, wormlike parasite costs growers about $1.5 billion annually. But resistant soybean varieties are not effective against all races of the nematode and usually have lower yields than susceptible varieties when nematodes are absent. The discovery of these peptides in parasite extracts opens a new path for scientists investigating naturally based controls for soybean cyst nematodes. The key may be the peptides’ potential involvement in regulating nerve transmission and muscle activity, as well as feeding and movement, in these pests. At least three different peptides have been observed in the nematodes grown on soybean plants. The peptides in soybean cyst nematodes differ from those in nonparasitic species, and their levels vary during the worms’ development. Researchers are focusing on those which would be most active in female nematodes, since they will lay the eggs that yield new generations of hungry, root-eating offspring.

Nematology Laboratory, Beltsville, MD
Edward P. Masler, (301) 504-8732, maslere@ba.ars.usda.gov

A 4-year study of weeds in central Iowa shows that success of integrated weed management relies on matching control strategies to the specific weed problem. In field tests, ARS scientists studied the emergence characteristics and seed persistence of four important weed species—common waterhemp, giant foxtail, woolly cupgrass, and velvetleaf. First-year emergence ranged from 5 to 40 percent for woolly cupgrass, giant foxtail, velvetleaf, and common waterhemp, in that order. There were no differences in emergence during the second and third years. Velvetleaf and common waterhemp seedlings continued to emerge during the fourth. But a greater percentage of common waterhemp seed persisted each year, with 12 percent of the original seed recovered after 4 years of burial, compared to 5 percent of velvetleaf seed. These findings are valuable to crop consultants and farmers as they evaluate weed problems and plan control programs. In addition, weed emergence was consistent over the varying environmental conditions that occurred during the research. This consistency supports the potential to develop tools to predict weed emergence over broad geographic areas. Such tools would improve weed control and reduce herbicide use by improving the timing and efficiency of field operations like scouting, tillage, and herbicide application.

National Soil Tilth Research Laboratory, Ames, IA
Douglas D. Buhler, (515) 294-5502, buhler@nstl.gov

Rice production may contribute to global warming by increasing methane emissions. But periodically draining the acreage in rice crops drastically decreases these emissions. Methane is a greenhouse-effect gas that has a 20-fold greater global warming potential than carbon dioxide (CO₂ ). Rice grows best in wet soil with its roots flooded. But flooded rice crops emit substantial amounts of methane into the atmosphere—especially when fresh organic matter, like plant residues, is added to the soil. ARS researchers found that draining the soil for two or three short periods during the growing season to aerate the crop’s roots may be an easy, environmentally friendly, on-farm practice that would help decrease methane emissions. The researchers also indicate that drainage and nitrogen fertilization need to be coordinated to minimize nitrous oxide emissions after reflooding the soil. Current world rice production is 384 million tons. Rice is the primary food for about 50 percent of the world’s population. Other studies have shown that up to 20 percent of global methane emissions worldwide come from flooded rice fields.

Crop Genetics and Environmental Research Unit, Gainesville, FL
L. Hartwell Allen, (352)392-6180, lhallen@gainesville.usda.ufl.edu

California rice growers can reduce threats to their crop yield from excess salinity, based on guidelines developed by scientists with ARS and the University of California Cooperative Extension Service. In California, rice is grown in flooded fields throughout a series of adjacent basins. California ranks third in U.S. rice production, behind Arkansas and Louisiana. In 1999, more than one-half million acres were harvested in the state. State regulations require that water be held in these basins for a certain period of time to allow pesticides used by rice farmers to degrade before the water is released into local waterways. In drought years, if the water is held too long, evaporation can concentrate salts to a level detrimental to plant growth. International guidelines developed in the 1960s use an electrical conductivity value of almost 2,000 milligrams of salt per liter of water as the threshold for salinity concerns. But for rice growers under California climate and cropping conditions, researchers showed that yield losses started to occur when levels reached about 1,300 milligrams of salt per liter of water. At certain growth stages, damage resulted from even lower salinity levels. Using guidelines developed with the researchers, regulatory agencies approved procedures for allowing emergency releases of the water if salinity levels increased to dangerous levels.

George E. Brown, Jr., Salinity Laboratory, Riverside, CA
Michael C. Shannon, (909) 369-4814, mshannon@ussl.ars.usda.gov