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SUNIONS – The game-changing 'cepas' that won’t make you cry

BASF develops first tearless, sweet onion available on the market.

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Sunions are a game-changer in the kitchen, offering an onion that is certified tearless by both the Sensory Lab of BASF’s vegetable seeds business  and the Ohio State University Sensory Evaluation Center.


Now you have one more thing to be thankful for this Thanksgiving season – a sweet onion that adds flavor to your food instead of bringing tears to your eyes while preparing it.

You can have the tastiness minus the messy preparation when cutting up that usually pungent vegetable. These are called  SUNIONS and you can give thanks to BASF for that.

How, might you ask, do you create a tearless onion that is not genetically modified, but developed through an all-natural crossbreeding program?

The idea came about 35 years ago – when BASF plant breeder Rick Watson wanted to create a mild, sweet onion that would be marketed during the winter months.



There are two onion seasons in the U.S. – winter storage season, when onions are shipped out of storage facilities for 9 months out of the year. Then there is a 3-month window of fresh onions during the summer.

“Within the storage segment, the onions are normally very hot and pungent by their genetic background, their origin,” said Jeff Boettge, Head of Crop Marketing and Strategy Biennials, BASF. “The breeder had an idea 35 years ago to create a variety that would actually be sweet coming out of that storage area.”

The concept of a tearless, sweet onion was a phenomenon – something that didn’t exist nor was done before and was genetically quite difficult to achieve, according to Boettge.

“We are the first to introduce a storage onion that has the combination of tearlessness and sweet flavor,” he added. “This variety that makes up the SUNIONS brand is really unique in the world of onions – it’s a real one of a kind.”

Indeed, SUNIONS are the first tearless onions available to the market, certified tearless through testing by the Sensory Lab of BASF’s vegetable seeds business and Ohio State University.

BASF supplies the seeds for the onion that make it tearless and sweet. Those seeds are later sold to growers who then produce the bulbs and sell them to consumers.

“Growing these onions is no easy task, you need to be a top-level grower to be able to pull this off,” Boettge added.


Jeff Boettge, Head of Crop Marketing & Strategy Biennials, BASF

Genetics always evolve

This breakthrough did not happen overnight, however. It took more than three decades looking for onion strains with less pungency, since that is related to the tearing or related to the sweetness of this vegetable.

“You take one strain, and you cross it with another strain, which has characteristics that you’re looking for, or what you call self,” said Boettge. “You take this onion strain and you self it, or you breed it to itself, you self-pollinate it; and then you start to create a more homogeneous strain of onion.”

But wait, there is more! Aside from this onion already being unique due to its sweetness and non-tearing quality, it has another interesting trait – the onion changes flavor over its storage time. The genetics of that variety are such that the onion becomes milder and sweeter in flavor over time. Normally, these onions are planted in the spring, harvested in the early fall and then they’re put into storage use – customized storage buildings. That’s where these cepas (Latin) begin their transition process to a sweeter level. Ergo, every day the SUNIONS become sweeter. Other storage onions, on the other hand, become hotter while stored, increasing in pyruvates (chemical compound in biochemistry relating to glucose) from 5-6 to as much as 8. SUNIONS pyruvate levels fall from 5-6 to 3 or less during storage. SUNIONS follow a tightly controlled flavor protocol and are shipped only once they are certified ready by internal testing.

“We want to sell onions only when they reach their peak flavor, when they really have an unforgettable consumer experience,” Boettge added.

And thankfully, this year’s targeted release for that variety is Thanksgiving season, just in time to make it to your family’s dinner table.

Since SUNIONS is such a versatile product, its mild crunchy flavor goes well on a salad or a fresh application. Additionally, that crunchiness and sweet-onion flavor minus bitter aftertaste also works well in cooked meals, such as stuffing.

“That’s the whole enjoyable experience – from the time you cut it, you don’t have that irritation and burning in your nose, or that smell on your hands – an yet you get that flavorful sweet-onion experience,” he said.

Boettge has been involved with SUNIONS since the very beginning. Starting out as a 24-year-old scientist working on this concept in a laboratory – to 35 years later – being responsible for the go-to-market strategy, branding and positioning of a once-in-a-lifetime onion – he could not be prouder of his team and the persons involved who brought this marvel to fruition.

“For myself and many of us who’ve been involved with this project from the beginning, it’s a tremendous feeling of success, because it involves so many people,” Boettge concluded. “It’s not just the onion breeder or the marketer, it’s the people who grow our seeds, test our seeds, and sell them; it was a true labor of love.”

To learn more about BASF’s unique SUNIONS project, click here.



        — A breakthrough in onion genetics, game changer as the first tearless and sweet onion available to the market

        —A long-day Western onion with flavor that grows milder and sweeter the longer it is stored


        —BASF spent 24 years & $5 million in incremental investment to develop and breed SUNIONS


        —Grown in the U.S.: Washington, Oregon, Idaho and Nevada


        —Shipped based on release date set by BASF, internal testing protocols to determine peak sweetness 


        —Not a genetically modified product; developed through an all-natural crossbreeding program


        —Tearless, sweet properties based on a stable genetic proprietary trait developed via traditional breeding                       


        —Commercial production of bulbs less subject to environmental factors than other sweet-onion varieties                                 

Published on November 19, 2020

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