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Open Access Publications from the University of California

Volume 60, Issue 3, 2006

Issue cover


When crop transgenes wander in California, should we worry?

The movement of transgenes into populations for which they are not intended remains a primary concern for genetically engineered crops. Such gene flow in itself is not a risk. However, we know that the transfer of genes from traditionally improved crops into wild populations has already resulted, on occasion, in the evolution of weeds more difficult to control, as well as an increased extinction risk for rare species. Just like traditional crops, genetically engineered crops could occasionally create the same problems. Currently in California, the movement of transgenes from most commercialized transgenic crops into wild plant populations is unlikely — the exception being canola. However, other transgenic plants have been field-tested in California, and if these become commercialized, in certain cases, transgenes are likely to move into the wild or into other crops of the same species. Such gene flow could result in various problems. The best containment for transgenes may involve risk assessment decisions by scientists embarking on projects to determine whether the proposed combination of organism and trait will pose any problems and if so, to determine how to create a safe product.

Careful risk assessment needed to evaluate transgenic fish

The reproductive biology of fish makes them particularly amenable to genetic manipulation. A genetically engineered or “transgenic” Atlantic salmon is currently undergoing federal regulatory review, and international research is being conducted on many other species. The innate ability of fish to escape confinement and potentially invade native ecosystems elevates the ecological concerns associated with their genetic modification. Escaped transgenic fish will not invariably result in deleterious effects on native populations, and careful risk assessment is required to determine the ecological risks unique to each transgene, species and receiving ecosystem combination. In response to public concerns about transgenic fish, California has developed stringent regulations for the importation, possession and raising of transgenic fish, and a California law prohibits their presence in waters of the Pacific Ocean regulated by the state.

What is the future of animal biotechnology?

Animal biotechnology encompasses a broad range of techniques for the genetic improvement of domesticated animal species, although the term is increasingly associated with the more controversial technologies of cloning and genetic engineering. Despite the many potential applications of these two biotechnologies, no public or private entity has yet delivered a genetically engineered food-animal product to the global market, and the sale of milk or meat from cloned animals and their offspring is currently subject to a voluntary moratorium in the United States. The animal biotechnology industry faces a variety of scientific, regulatory, ethical and public acceptance issues. Effective and responsible communication among scientific, community, industry and government stakeholders will be required to reach a societal consensus on the acceptable uses of animal cloning and genetic engineering.

Conservation tillage production systems compared in San Joaquin Valley cotton

Tillage operations, including preplant soil preparation, in-season weed control and postharvest stalk management, can account for 25% or more of overall cotton production costs. These operations reduce soil organic matter and contribute to air pollution. Conservation tillage practices similar to those used successfully elsewhere in the Cotton Belt may be a viable means for increasing profitability and improving soil in San Joaquin Valley cotton fields. In a comparison of reduced-tillage production methods, conservation tillage planting and stalk-management systems had yields comparable to those of standard tillage practices in two back-to-back cotton crops in Riverdale, Calif. These reduced-till systems decreased the number of tractor operations by 41% to 53%, fuel use by 48% to 62%, and overall production costs by 14% to 18%.

Conservation tillage and cover cropping influence soil properties in San Joaquin Valley cotton-tomato crop

Following 4 years of a cotton-tomato rotation on the west side of the San Joaquin Valley, conservation tillage and cover crops altered physical and chemical properties of soil. In conservation tillage systems, bulk density decreased and available concentrations of nitrate and phosphorus increased. In contrast, the conservation tillage system redistributed potassium to the surface of the soil, lost organic matter and increased salt concentrations, all potentially detrimental to plant growth. Cover cropping, on the other hand, increased soil organic matter regardless of the tillage treatment, and increased potassium concentrations. By cover cropping, farmers in this region may improve their soil quality; however, the benefits of conservation tillage to soil quality are fewer and will require more research to determine long-term effects.

Dietary quality is not linked across three generations of black women

Many nutritionists believe that food habits are passed on from one generation to the next, influencing dietary quality. However, we studied the food habits and dietary quality among three generations of biologically related black women and found that there was no correlation or relationship. In addition, we identified culturally acceptable food sources of nutrients most likely to be lacking in the diets of black women. The increased consumption of these foods may help reduce the high rates of chronic diseases among black women in California.

Western cattle prices vary across video markets and value-adding programs

We analyzed video auction sales in the western United States from 1997 to 2003, in an attempt to answer two long-standing questions about the economics of cattle ranching in California. First, as expected, ranchers received lower prices for cattle sold here compared to prices received by ranchers in the Midwest; this is due to the cost of transporting cattle to Midwestern feedlots. Second, some (but not all) “value-adding” production and marketing practices — such as preconditioning, Quality Assurance Programs and natural beef production — did raise prices received by ranchers. We report on the average location discounts and quality premiums for several market regions.