By Elizabeth Niven
There are two types of commercially grown tomatoes: there’s the fresh market tomato, hand picked from the field prior to being ripe and sold individually; and the processing tomato, mechanically harvested when ripe, quickly transferred to a manufacturing plant and made into tomato paste, tomato sauces, ketchup, whole canned tomatoes and juices.
While individually, the processing tomato is anonymous, the popularity of the end products is immense. U.S. consumption is on the rise because of the popularity of pizzas, pastas, salsas and ketchup.
With that in mind, Monsanto tomato-research teams in Israel, Italy and California, are asking, “How can we produce more tomatoes per unit of growing area through the seed?”
In the past, row-crop researchers have focused on increasing yields as a major attribute in developing seeds. However, for vegetables, yield has never been the focus. For tomatoes, breeding has focused on factors like disease resistance—which in turn protects the necessary yield capabilities of the tomato plant—but never on yield itself.
“Our current goal is to set up a breeding program that focuses on yield,” said Mike Kerns, Monsanto’s trait genetics lead. “Monsanto teams are showing that breeding principles, such as heterosis or hybrid vigor, do exist in crops such as processing tomatoes and can possibly be utilized to create a step-change in commercial hybrid yields.”
In other words, hybrid vigor or heterosis is the improved or increased function of a plant or animal in a hybrid offspring. If researchers can create hybrid vigor in tomato yield, this has the potential to change the industry.
Currently, the research spans three continents, with the majority of the work taking place in Israel under Monsanto researcher Amit Gur with support from team members in Italy and California. Because processing tomatoes are picked ripe and immediately transferred to processing facilities, these areas have the tomato-growing climate and the processing infrastructure.
“So far the team has been able to demonstrate for the first time, in a systematic and measurable manner, the existence of best-parent yield heterosis in elite processing tomatoes,” said Gur. “On average, hybrid yield is 50 percent higher compared to the better parent in each cross. At the same time, we’ve demonstrated that there is substantial variation in the level of heterosis. This variation is our substrate, or basis, to select the best hybrid combinations and best combiner parents for breeders to focus.”
Another aspect of the project focused on producing data to broaden perspective on historical yield gain in processing tomatoes. In a multi-location experiment that took place last summer in California, Gur’s team showed that although there was a significant genetic yield improvement of 1.2 percent per year within the process tomato market, leading varieties in this market are not showing the same rate of genetic gain.
“This information is beginning to go out to processing tomato breeders now,” said Kerns. “This will change how they do things, which will be incremental, but will allow them to choose testers in their programs and better predict what line combinations would create the most productive, in terms of yield, commercial hybrids.”
This has the potential to lead the industry in developing consistent gains in processing tomatoes. From there, the knowledge can be expanded to other types of tomatoes and crops.
In the meantime, the test sites are producing an abundance of tomatoes. In Israel, Monsanto contacted Leket, a local food bank that distributes food to more than 290 not-for-profit organizations serving the needy, and donated 100 tons of tomatoes. That’s a lot of tomato sauce!