“Science of Breeding Tomatoes” virtual field tour links students with space agriculture and an international tomato breeder
- Diane Baltaz
- 21 hours ago
- 4 min read
By Diane Baltaz
International commercial tomato breeder Kelsie MacLellan of HeinzSeed, the agriculture and breeding unit of KraftHeinz in Leamington, not only develops tomato varieties for use around the world but also sends seeds into outer space.
MacLellan, a Brantford native, recently shared her work at HeinzSeed with approximately 50 registered elementary and secondary school classrooms (almost 1,000 students) through a virtual field trip entitled “Science of Breeding Tomatoes”, organized by AgScape, Ontario’s non-profit agricultural education association.
This virtual field trip was done in partnership with Let’s Talk Science, and was part of AgScape’s 2025 Canadian Agriculture Literacy Month (CALM) initiative, which takes place each March, said engagement and communication specialist, Sheri Budhram.
As a bonus, Let’s Talk Science of London sent participating classrooms tomato seeds that were grown and germinated in space through the “Tomatosphere Adventure” – a project which sends seed into outer space which are then sent to classrooms to use in science experiments. It was part of an educator resource pack that was distributed to educators across Ontario, said Budhram.
Participating classrooms receive two free packages of tomato seeds: one of seeds sent into space; the other untreated “control” seeds. Students plant the seeds, then chart and compare growth differences, reporting results to the Tomatosphere.
Begun in 2001, the Tomatosphere Adventure is part of Let’s Talk Science – the non-profit agency which encourages science, technology, engineering and mathematics (STEM) to youth from Kindergarten to Grade 12. The seed comparison experiment provides a hands-on mean of building scientific inquiry and investigative skills for participating students.
“We thought it would be fun to work with Let’s Talk Science who have the Tomatosphere program as well as Kelsie from HeinzSeed, since the seeds that are sent into space are from Heinz,” said AgScape education coordinator Madison Lammers.
“It’s true,” MacLellan confirmed after the virtual tour. “HeinzSeed partners with NASA on the Tomatosphere project. We supply them with seeds to take to the International Space Station.”
MacLellan’s status as an international breeder intrigued the students. Born in Brantford, she became attracted to genetics while studying biology in high school. MacLellan studied population and quantitative genetics at the Universities of Guelph and Ottawa, spending summers working at the Ontario Crops Research Centre near Simcoe.
This geneticist began working for HeinzSeed in 2011 and is now responsible for international breeding, supervising and tracking the performance of potential new tomato varieties around the world. In fact, MacLellan began her virtual conversation by saying that she had just returned from examining field trials in Chile on the previous day.
During the dialogue, MacLellan answered multiple chat box questions from students and showed two videos of her greenhouse research that she created for the tour.
MacLellan said that she only breeds hybrid varieties that can be mechanically processed into products such as ketchup, BBQ sauce, diced and canned tomatoes. She selects varieties suitable to the varied growing conditions of the world’s largest tomato-growing countries in the world, including Brazil, Chile, Spain, Portugal, Italy, and parts of North America, and conducts field trials in these locations each summer.
MacLellan creates 300 new tomato varieties annually; but she elaborated, “I narrow these down to one or two new varieties per year, after five years of selective breeding and evaluation. It’s a long process to evaluate and replicate them in different countries and growing conditions.”
HeinzSeed’s tomatoes are developed through conventional plant breeding, not genetic modification, said MacLellan. One of her videos explained the parts of a female tomato flower and then demonstrated how MacLellan’s team use a vibrating pollination tool to replicate pollen moving from a male plant to a female in order to obtain a proper DNA profile. This genetic profile creates a new, high-yielding tomato with the necessary chemistry to be more resistant to pathogens and to reduce fungicide and pesticide use.
The students’ questions centred upon the pollination process, the challenge of keeping the 300 test varieties separated, the versatility of specific commercial varieties, seeding times, and clarification about what constitutes a hybrid.
When asked about whether one must always hand pollinate hybrids, MacLellan replied, “Yes, all commercial varieties are hand-pollinated - even those that come in the 100,000 seed packages. We hand-pollinate each seed. It explains why tomatoes are expensive.”
When a Humberview secondary school student asked, “How many times do you need to pollinate?”, the international breeder replied, “Once per flower – either it’s successful or it’s not – we see that in a week or it turns black and fall off.”
When another student asked what the largest tomato she developed was, MacLellan grinned and replied that she once created a 180-gram hybrid.
The Let’s Talk Science portion used a video filmed at the International Space Station. In it, Thomas Pesquet of the European Space Agency, outlined tomatoes’ potential for space agriculture for long-term missions before inviting student to join the Tomatosphere classroom investigations.
Pesquet said that he spent six months doing plant research in space at the time of taping. “We are already growing lettuce here at the space station, but no salad is complete without tomatoes.”
The astronaut explained that “tomatoes can be a space super food” because they can be part of a plant-based system to enhance life support systems during space travel. They provide nourishment and water through transpiration from their leaves. The plants also convert light energy and carbon dioxide exhaled by astronauts into oxygen.
‘This is where the Tomatosphere comes in,’ said Pesquet. “Will tomatoes grow the same in space as they do on earth? Help us find out.”
The virtual tour ended with a question which asked MacLellan what is her favourite part of being a tomato breeder.
“My job is very cyclical,” she replied, grinning again. “My job in February is very different from what I do in April or in August. I’m not doing the same thing every day.”
MacLellan added, “Therefore I suggest that you think about pursuing an agricultural job and not just medical if you are interested in scientific research.”
“It was great to work with both AgScape and Let’s Talk Science,” said MacLellan after the virtual field tour. “In general, I am very passionate about scientific education and love to participate whenever I can.”
The virtual tomato breeding tour and AgScape’s previous online events can be found on Youtube.
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