Date: Jan 01, 2013
Magazine:
January 2013 - New Seed Variety Issue

A generation ago, the promise of breakthroughs involving gene technology, led some to believe that developing new seed varieties in the future might be a more simple process yielding quick results.  Many consumer articles spoke of the potential of a square tomato or watermelon for easy slicing or vegetables that tasted as sweet as candy but were still packed with great nutrition.

It is true that there has been in advancements in many aspects of seed breeding, but it is still a painstakingly slow process that takes many years to bring a brand new variety with superior traits to market.

In fact, Jeff Zischke, director of research for Sakata Seed America Inc., Morgan Hill, Calif., said it still takes about the same time as it did a generation ago, because it still involves the same process.  “In most crops, you still have to go from seed to seed for five or six generations to create uniform lines and then make the crosses,” he said, “and that takes the same amount of time.”

However, he said what has changed tremendously is that because of the use of molecular markers, the seed breeders can target their work much more efficiently.  He said specific traits can be transferred into existing varieties much more quickly, and the breeders have reduced the amount of unusable plants that they are looking at in the field.

In a separate interview, Gabe Gusmini, global head of Traits & Technology Vegetables Research & Development for Syngenta, made the same point.  “It depends what you are talking about when you say a ‘new variety,’” he said.  “If it is an existing variety and you want to add a specific trait to it, we can do that more quickly.”

But he agreed that if the goal was to develop a brand new variety combing many different traits, it would take about the same time as it did years ago.  “The timeline hasn’t changed that much but the variety is going to be much more complex than it once was,” he said.

Zischke agreed stating that there is no such thing as “one powerful trait that is going to make a new variety.”  He said each new variety has many different traits that make it worthy to be brought to market.

As a point of reference, it takes about four or five years to create new parental lines.  These new lines are then tested by making crosses in many combinations and over a couple of years of field trials the best hybrids are selected for advancement.  It can take three to five years from first look until a product is named and being sold.  “You are still looking at seven to eight years at the minimum for a new variety,” Gusmini said.

And he reiterated that the new variety developed today is going to have many different complex traits.  It might have disease resistance to half a dozen diseases and have superior yields as well as good flavor and texture, and adaptability to many different environments.

Both researchers said the use of markers does allow seed breeders to add traits in the breeding process using known markers and they know, from experience, that those traits — such as disease resistance to a particular problem — will perform as they are supposed to in the resulting variety.  The seed breeder does not have to run trials in the field to see the trait is there if the marker is known to be a reliable indicator.  For example, Zischke said there is a marker for resistance to tomato spotted wilt virus.  This is a very important problem for tomato growers and virtually every new variety can be equipped with this trait, just as every car coming off the assembly line in Detroit can be equipped with anti-lock brakes.  It’s a breakthrough that has become commonplace, but doesn’t mean the car — or the tomato — can be created any faster.

 

Dihaploid Breeding

Though basic seed breeding is time consuming and takes about the same amount of time as it has in the past, both researchers did discuss one advancement that does have the ability to reduce breeding time.  Gusmini said dihaploid breeding can reduce time by altering the normal breeding process and creating carbon copies of parental lines rather than crosses.

Zischke explained a bit further.  “This is a tissue culture technique used to develop uniform lines from a population in one generation.  It is successful in some species and can rapidly enhance the speed of the parental line development.”

He cautioned that in using this technique the breeder misses the opportunity to select along the way, and consequently, the end result can be a lot of uniform plants that don’t produce favorable results.  But he added “If you select your populations carefully, this approach can be very effective and reveal good finished inbreds in one year.  You then need to make test crosses to determine if the selected lines make good parents.  This can shave some two to three years off the inbred development process.  Combining this technique with molecular markers, a breeder can stack many important traits into finished lines.”

 

Genetic Mapping

Both researchers stressed that the evolution in genomics and genetic mapping is benefitting seed breeding and should be a huge benefit as it moves forward.  Genomics involves mapping the entire DNA sequence of an organism. Zischke said this should lead to the identification of sequences that control beneficial traits of interest and allow breeders to transfer from related germplasm.  For example, if you need cold tolerance in a specific tomato variety, you should be able to find it without needing to go outside the species.  Going outside the species — for example finding that cold tolerance gene in a flounder and transferring it to that tomato plant — in a nutshell is the type of work that drives the anti-GMO people nuts…and is the perception that has led to the backlash against genetic engineering.  Genomics will foster a better understanding of the function and regulation of genes existing within the targeted species and broaden a plant breeders options for trait development.

Gusmini agreed stating that genetic mapping is the number one breakthrough that has resulted in much more targeted seed breeding work.  He said the targeted approach is much more efficient and allows breeders to take far fewer new varieties through the entire seed breeding process.  As he looks down the road, the Syngenta research expects genetic mapping will continue to help breeders find complex markers for traits such as taste, flavor and texture that will allow them to build better varieties.  From his standpoint one of the biggest advantages of technological advances — and especially the significant reduction in costs involved in genetic mapping — is that it allows the vegetable crops to get their fair share of research time.  He said the gap has narrowed between the agronomic crops (cotton, wheat, soybeans) and vegetables in terms of research because genetic mapping makes it affordable.

 

Computer Modeling

Both Gusmini and Zischke said seed breeders and seed marketers are benefiting tremendously by technology advances that allow for better and faster computer modeling.  And this advancement should continue to yield results as more and more data is available to feed into the computer and help seed companies forecast performance.  Gusmini expects computer modeling to grow and foresees a time when seed breeders across the world can share data that doesn’t offer a competitive advantage that will benefit the entire industry by giving everyone access to more data points.  He explained that it would be possible, for example, to share information about average yield in a trial for a species under specific climatic conditions without sharing the proprietary information about the specific lines used in the research.

Zischke said statistical modeling for yield and other attributes is a great time saver for a seed company.  He said computers do help determine where a particular variety might work well and adapt to similar climatic situations under which it has been trialed.

 

Back to the Future

Though discussing computer modeling, genetic mapping and new technologies, both researchers however, did bring the discussion back to some time-honored traditions that will probably never change.

Gusmini said the mantra of the past when “yield, yield and yield” were the three most important traits for any growers is still “absolutely true.”  Though he did allow that how a grower defines yield is a bit different.  He said it is now a complex equation that includes what he called “yield stability.”  Growers are not just looking for tons per acre but usable product.

For his reminder that as things change, they also stay the same, Zischke said that “the most important person in the breeding process is still the breeder with his eyes on the crop.”

He said molecular markers can help infuse a potentially new variety with many important traits but still the most important thing is what the breeder sees in the field and how he interprets that.  Gusmini agreed.  “At the end you need to verify (with your eyes),” he said.  “After all, that is the scientific process.”  Hypothesize; put the markers in the potentially new variety; and then grow the crop to see if it performs as expected.

“In the early 1980s, with genetic engineering upon us, some people thought that in the future the plant breeder wouldn’t really be needed anymore,” said Zischke.  “That hasn’t turned out to be true.”

He said that belief led many a young science-minded grad student to take his plant science careers in the direction of molecular biology rather than plant breeding.  But that trend is changing.  In fact, Zischke said the recession has helped.   While other sectors of the economy were dragging, “agriculture kept chugging along.  Consequently, we are seeing an upsurge in students pursuing plant breeding degrees.”

Which is a good thing, because moving forward it appears that seed breeding — the old fashioned way but with a boost from genetic research and computers — will still be an important driver in production agriculture.

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