Tomatoes Bred and Selected in the Industrial Food Production System are Losing their Sweetness

By Molly Redfield

A recent study published in Science magazine reveals that cosmetic breeding has altered the genetic expression of tomatoes cultivated within the industrial food production system, both decreasing their natural sugar content and making them less tasty.

Cosmetic breeding has altered the genetic expression of tomatoes (Photo Credit: Vegetable Matter)

In industrial agriculture, farmers tend to pick produce before it has the chance to ripen naturally. This ensures that after packaging and transportation food is not rotten when it arrives at its supermarket distributors. For the last 70 years tomato breeders have used uniformly light green tomatoes because farmers can more easily see their lighter color in the trees and, after they are picked, packaged, and transported, these fruits become evenly red on supermarket shelves. Tomatoes that are darker when they aren’t ripe, however, are more difficult for farmers to find. The uniformity of their coloring is also less discernible. For these reasons, breeders avoid selecting darker green tomatoes. In the wild, however, these tomatoes are more prevalent than their lighter green counterparts.

Wild tomatoes that are darker green when unripe have a transcription factor that has been bred out of many cultivated varieties. Transcription factors are important because they are proteins that can turn certain gene sequences on and off. This particular transcription factor, SIGLK2, interacts with the sequence of genes coding for chloroplast production.  Chloroplasts are responsible for photosynthesis, or the process of converting light energy into sugars, and also for the green color in plants. Consequently, when farmers breed for tomatoes that are uniformly light green when unripe, they are inadvertently also choosing tomatoes that will have less natural sugar content and will, ultimately, not taste as sweet.

By inserting SIGLK2 into cultivated varieties, however, scientists found an up to 40 percent increase in both the sugars fructose and glucose. Additionally, lycopene content rose. Lycopene, which is an antioxidant, has numerous health benefits. These health benefits include enhanced bone health and cancer prevention.

In addition, picking fruits from trees before they are ripe decreases the nutrients they would receive as they are ripening. In fact, an estimated 80 percent of the fruit’s sugars are produced in the plants leaves and then later transported to the fruit as it ripens.

Given the findings of this recent study, several questions still remain. What other long-term impacts does industrial agriculture have on the nutritional value and taste of its produce? Furthermore, what alternative types of agricultural practices might lead to more nutritious, better tasting food?

Molly Redfield is an intern with the Nourishing the Planet project. 

To purchase State of the World 2011: Innovations that Nourish the Planet please click HERE.

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