What it's like to breed onions at De Groot en Slot

Curious what it's like to be an onion breeder at De Groot en Slot?

Onion breeder Fetze Admiraal tells you more in this article.

An interest in genetics runs in Fetze Admiraal's blood. As a child, he was already crossbreeding chickens, but it wasn't until his studies that he discovered his passion for plant breeding.

"I love seeing a grower happy with the yield of one of our varieties."

Why did you become a plant breeder?

"I initially studied Environmental Engineering, but it turned out not to be the right fit for me. During my first year at Van Hall Larenstein University of Applied Sciences in Deventer, my interest in genetics—which I had already developed as a child—returned. From that moment on, I focused on plant breeding by doing internships at breeding companies, choosing plant breeding electives and completing a minor in Biotechnology."

How did you end up at De Groot en Slot?

"After graduating from Van Hall Larenstein, I had to decide whether to continue my studies in Wageningen or start applying for jobs. In the end, I chose to start my career because there were plenty of interesting vacancies available and I felt I was ready to leave student life behind.

After speaking with several potential employers, I chose De Groot en Slot, where I've now been working for 14 years. What appealed to me was the international nature of the job and the opportunities to develop within so many different markets. And of course, the right feeling is important too—and it just felt right."

What do you enjoy about working here?

"The variety in the work: from evaluating field trials to consulting with our research departments and collaborating with colleagues around the world. De Groot en Slot has been working together with Bejo for more than 50 years. Our joint breeding team consists of eight breeders in the Netherlands, two in the United States, one in Italy, one in China and one in Argentina. The breeders are supported by a team of assistant breeders.

I also really enjoy working in a relatively small, flat organisation with an informal atmosphere. On top of that, there are plenty of opportunities to develop within international markets."

What does the breeding season look like?

"The activities vary throughout the year and depend on the breeding team you're part of. For the extra-long-day group, which includes the Rijnsburger onions, January, February and March are dedicated to selecting parent lines, assessing storage performance and discussing the results of the different seed lots from our field trial locations.

These discussions involve the entire Rijnsburger team, consisting of four breeders, one assistant breeder and one field trial coordinator. Sometimes we spend an entire week in the meeting room, so it definitely helps to be comfortable sitting for long periods!

During this period, the onions are also prepared by carrying out an initial selection. Only the very best onions remain for the final selection before they are planted in the greenhouse."

"In April and May, the selected onions are planted in the greenhouse for seed production. At the same time, screening trials and selection fields are sown for the next breeding cycle. Once all the onions have been planted, it's a good time to check the seed production records in both the database and the greenhouse.

June and July are all about flowering and seed set. During this period, we regularly visit the greenhouse seed production locations to make sure everything is developing as expected. We also visit the various Rijnsburger and onion set trial fields across the Netherlands. The crops are assessed for characteristics such as off-types, disease susceptibility and red discolouration. The onion set trials, including both overwintering and spring onion sets, are also evaluated. We assess colour, shape, yield, bolting, disease susceptibility and give an overall performance score.

August and September are dedicated to evaluating the Rijnsburger screening trials in the main growing regions. Both standing crops and windrowed onions are inspected and assessed. October, November and December are focused on harvest, preparing for storage evaluations and bulb selections. During this period, the other genetic groups, including onion sets, are also evaluated. It's the busiest time of the year when it comes to selecting, assessing and meeting."

You are a Rijnsburger onion breeder at De Groot en Slot. What is the main breeding focus?

"Our main focus is still on the classic Rijnsburger characteristics, such as skin firmness, bulb firmness, shape, colour and yield. At the same time, we're placing increasing emphasis on flexibility and stability, because both current and future growing conditions demand it.

A robust onion also needs strong disease resistances—for example against Fusarium, pink root and downy mildew—as well as a powerful root system and vigorous foliage. That way, even in dry years, growers can still produce onions of the right size and market quality."

What does the perfect onion of the future look like?

"The onion variety of the future needs to be robust and versatile. It should combine multiple disease resistances with a strong root system and upright, vigorous foliage to ensure stable yields year after year. I also expect the trend towards breeding for specific market demands to continue, just as we've already seen in other markets."