MAY 2026  |  SEEDWORLD.COM/EUROPE  I  SEED WORLD EUROPE   I   37
that deliver higher yield within shorter 
seasons, reducing exposure to both biotic 
and abiotic stress, while also lowering 
water, fertiliser and pesticide inputs. Time 
has become a breeding trait, Djordjevic 
explains. Finishing seven to 10 days ear­
lier can mean avoiding the worst stress 
events altogether. In practice, he points 
to mini-seedless types that mature earlier 
than benchmark varieties as a clear exam­
ple of using maturity timing itself as a cli­
mate-risk management tool.
Ashish Patel, head of germplasm 
development – cucurbits at Syngenta 
Vegetable Seeds, frames climatic resil­
ience as the pursuit of stable performance 
under unstable conditions. The focus is on 
broad adaptability to abiotic stresses such as 
heat tolerance, cold tolerance and soil pH 
adaptability. Pairing data-driven genomic 
selection with intense multi-environment 
trialling helps find the right product posi­
tioning for changing market environments.
Juan Antonio Fernández, watermelon 
breeder at Semillas Fitó, notes that recur­
rent droughts are becoming more common, 
and growing conditions in formerly temper­
ate areas are becoming harsher. Even where 
specific drought-tolerance research exists, 
he describes a broader selection direction: 
traits that help in arid conditions, includ­
ing more powerful plants and root systems, 
drought and heat tolerance, and resistances 
that help maintain canopy and keep the 
plant at full capacity.
Megan Calvert, seedless watermelon 
breeder at Bayer, describes how her pro­
gramme tests material in some of the most 
challenging areas in the world to ensure 
released varieties perform consistently 
and adapt to multiple environments. And 
because conditions are expected to become 
more extreme, the programme is also con­
sidering how production areas may shift 
and what will be needed going forward. She 
points to wild relatives in germplasm banks 
that show promise for challenging condi­
tions, now being evaluated for future use.
Together, these answers show climate 
breeding as more than “heat tolerance”. It’s 
a systems approach: plant architecture, root 
strength, maturity timing, stability across 
environments, and the ability to keep eating 
quality intact even when the plant has been 
stressed.
SEED PRODUCTION: THE 
SEEDLESS BOTTLENECK
Seedless watermelons may be the consumer 
default, but they bring their own production 
constraints, particularly around the creation 
of triploid varieties and the challenges in 
seed production.
Fernández explains that seedless pro­
duction carries two major hurdles: pro­
duction of tetraploids (female lines) and 
production of triploids (tetraploid x dip­
loid). Both are complex, and both come 
with a learning curve that takes years. His 
emphasis is not just on technique, but on 
discipline: strict protocols for planning and 
product advancement, and careful selection 
of production areas, because seedless seed 
production is more demanding climatically 
than seeded.
Even without a long technical expla­
nation, the implication is clear: breeding 
doesn’t end when the variety exists geneti­
cally. It must also be reproducible as a com­
mercial seed product. For seedless systems, 
that additional step is often where timelines 
stretch and costs climb.
POLYGENIC TRAITS: WHEN THE 
ENVIRONMENT ARGUES BACK
Breeders can identify a delicious fruit in 
one field, only to find that the same genet­
ics behave differently elsewhere. That is 
the reality of polygenic traits and geno­
type-by-environment interactions.
Francisco Xavier Lopez Fernandez, 
global crop coordinator at Semillas Fito, 
lists fruit size, sugar content and earliness 
as examples of polygenic traits. Tackling 
them requires selection under high pressure 
across different environments and locations, 
both in parental lines and in the hybrids 
where those lines are used. It is repetitive, 
sometimes exhausting work, but it is how 
breeders separate “looks good once” from 
“works reliably”.
Calvert adds that testing in multi­
ple environments and multiple countries 
remains essential to account for differ­
ent factors impacting traits. But she also 
points to newer statistical methods, such 
as genomic selection, which can consider 
high-density genotyping and increased 
phenotyping to resolve some of those inter­
actions. The practical outcome is better 
decision-making: selecting the best vari­
ety for a specific market based on multiple 
interacting factors, so growers can have 
confidence that seed choices fit their con­
ditions.
This challenge connects closely to 
Djordjevic’s breeding strategy. He describes 
traditional hybrid breeding as simultane­
ously tackling more than 40,000 genes. 
His entire breeding nursery is genotyped 
at the individual plant level and is delib­
erately focused on maximizing heterosis, a 
hybrid vigor. Strong hybrid platforms are 
the vehicle for future innovation e.g., strong 
varieties allow them to add single-gene 
traits, including those that may come from 
emerging technologies like gene editing. In 
his framing, robustness at the hybrid level is 
not optional, it is what allows innovation to 
survive real-world environments.
Watermelon trial fields are essential for evaluating performance under real-world conditions, from yield 
stability to fruit quality. Breeders assess traits such as uniformity, stress tolerance and internal quality 
across diverse environments to ensure consistent results for growers. Photo: Syngenta Vegetable Seeds

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