There are other reasons for this lull. Many genetic markers have only been discovered this decade, prompting Mackill to predict a large increase in molecular breeding next decade. And, he adds, while seed firms like Monsanto and Pioneer have invested heavily in molecular breeding, none of their research has been published, due to competition.
Over the past two years, Pioneer has stressed its use of molecular breeding to improve its soy varieties, most of which are also genetically modified. The base for Pioneer's soybeans is relatively simple, and a lot of natural variation lies outside the varieties typically used, said Soper, Pioneer's soybean research director.
"In the future," Soper said, "we'll be using some of these new molecular tools to fish some needles in the haystack that we can pull out."
For a century, individual breeders, scientists and firms have bred crops for their capacity to improve yield -- the amount of crop grown. Yield is a far more complex trait than Mackill's flood tolerance. It is not a matter of one or two genes -- it takes "dozens if not hundreds of genes to get what farmers perceive as yield," Soper said.
"We've done extensive modeling to find genes that have been selected over time," he said. "Since we know that plant breeders have bred for yield, we have a theory that a lot of the genes have increased in selection over time."
These genes have had tangible yield impacts, some increasing soy's production by up to a bushel. Over the last five years, Pioneer has learned much about these individual genes, and is now probing how they interact, Soper said.
"It's not about simply adding genes and stacking them," he said. Combine two genes that separately increase yield, and suddenly the improvements disappear. Add two others together, and the effect doubles. "It's complex," Soper said.
Despite this complexity, Pioneer is promising to expand its commercial molecular breeding program to corn next year -- a crop that has proved stubbornly resistant to marker-assisted improvements.
Of maize and monkeys
Corn, also known as maize, is genetically complex -- its genome, only recently sequenced, was much more difficult to piece together than the human genome. Its genes have been active over the past 5 million years, behaving selfishly and scrambling the genome, giving the crop an incredible diversity, Cornell's Buckler said.
"There is as much diversity between any two maize varieties as between chimp and man," Buckler said. "This is why breeding efforts have been so successful in maize."
Partially because of this complexity, however, the type of molecular breeding used for scuba rice has had limited success for corn. Buckler made this clear in a recent paper looking at what genes influenced the time corn took to flower, where the many genes surveyed had little impact on the trait.
"There really are no big effect [genes], at least for flowering time," Buckler said. "That has an implication of how we're going to make progress in the future. ... [It] means we can make very powerful predictions, but also means it will be harder to figure out individual genes."
Given the limited power of individual genes in corn, Buckler has established a research method called nested association mapping. His lab grows row upon row of corn in upstate New York, crossbreeding one reference strain -- the widely grown B73 -- with 25 different varieties. (It took seven years to breed the populations.) These diverse populations, combined with high-powered computation, should allow breeding predictions for a variety of incremental improvements in traits like drought tolerance, nitrogen use and aluminum tolerance.
Buckler's lab and many others have begun to use what is considered the next step in molecular breeding, called genomic selection. First pioneered by cattle scientists earlier this decade -- there is an actual field called "bovine functional genomics" -- genomic selection capitalizes on computing power and the large number of markers now available to rapidly make breeding decisions based on every gene influencing a trait, not just a few.
"[It] allows very accurate predictions even with small effects," Buckler said.
Buckler's fields have already helped identify genes that provide a threefold increase in the vitamin A provided by corn, turning ears a brilliant orange. The crop will be used by HarvestPlus in Zambia, part of its effort to develop staples that contain nutritional, and not just yield, improvements.
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6 Comments
Add CommentWhen you refer to "increasing soy's production up to a bushel", do you mean per plant, per hectare, per acre, per square mile ... ?
Reply | Report Abuse | Link to thisPaul Ehrlich saw a pending population crash that didn’t happen. The crash didn’t happen because of the advances in agriculture. Commercial fertilizer, plant breeding, and genetically engineered crops have brought about abundant crops that are sufficient to feed our world’s human population of 6.8 billion
Reply | Report Abuse | Link to thisGenetically engineered (GE) crops are a lifesaving breakthrough for the developing world because plants have been created that contains all the essential nutrients for human health. It is a tragedy that well meaning “greens” in Europe have poisoned the minds of Africans against the use of GE crops. This campaign has caused the starvation of untold numbers of Africans.
The greens and organic farmers need to look into this biology and accept molecular breeding and GE seed production as they are engineered to produce the hardiest, most nutritious and non-allergenic foods.
We need to cope with feeding a growing human population on a planet that is losing agricultural land to climate change. Our hope is that molecular breeding and genetic engineering may increase our crop productivity to keep pace with the nutrition needs of our world’s population.
Animal breeders could do similar things to help prevent genetic disorders like hip dysplasia caused by excessive and unscrupulous inbreeding.
Reply | Report Abuse | Link to thisBushels per acre is the standard unit of grain yield for soybeans in the US. One bushel equal 60 pounds of grain at 13% moisture.
Reply | Report Abuse | Link to thisThe problem here is that there are unknown nutrients and other chemicals/compounds that are beneficial to human health. These nutrients haven't yet been discovered or identified.
Reply | Report Abuse | Link to thisThere are millions of people out there who hate monsanto and everything they stand for - agent orange, gm, round-up and else. Given this fact and the economic need (if there is one, that isn�t made by ourselfes), molecular breeding will hopefully be, what GMOs want to stand for: A clean, new way without any impact to nature or our health.
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