Trade-offs in breeding tomatoes for processing

A new study from researchers in Italy is offering a century-spanning insight into tomato breeding: from heirlooms to today’s high-yield processing hybrids. 

This comprehensive assessment published in the Journal of Food Composition and Analysis highlights the trade-offs between yield and fruit quality in processing tomato breeding over the past century, providing strategic insights for developing future varieties. Breeders have significantly increased marketable yield and Brix yield, while simultaneously lowering key quality traits such as ascorbic acid, thiols, and several volatiles, some of which are flavour-related. 

Researchers tested ten tomato varieties, released at different times, growing them together under the same field conditions in northern Italy. They analyzed key traits: sugars, acids, amino acids, vitamin C, thiols (like cysteine and glutathione), carotenoids, volatile aroma compounds (VOCs), and phenolic antioxidants. They also tracked the genetic relationships among varieties.

The key findings were:

• Yield went up steadily across decades (about 0.47 % per year).
• Guaiacol (an aromatic VOC important for tomato flavour) rose by 1.66 % per year.
• But levels of ascorbic acid (vitamin C) dropped by 0.47 % per year, while cysteine and glutathione fell by 0.87 % and 1.06 % per year, respectively.
• Several other VOCs—like benzaldehyde, hexanal, nonanal, and others—also declined over time 

They also found an inverse relationship between yield and both VOC levels and cysteine content: in general, the higher the yield, the lower those quality compounds. Phylogenetic (family tree) analysis showed some flavour‑related traits still followed inherited patterns in modern lines.

The study concludes that improving tomato yield has been highly successful—but often at the expense of flavour and nutritional quality. While some aroma compounds like guaiacol increased, essential nutrients and other flavour molecules declined. These findings reveal the trade‑offs between production efficiency and taste/nutrition. 

For future breeding, the study suggests leveraging ancestral (heirloom) traits to balance high yield with good taste and nutrition in new processing tomato varieties.

Reference: Andrea Burato, Aldo Tava, Elisa Biazzi, Mario Parisi, Pasquale Tripodi, Roberto Lo Scalzo, Giulia Bianchi, Valentina Picchi, Domenico Ronga, Changes in processing tomato fruit quality in heirloom and modern varieties developed over the past decades. Journal of Food Composition and Analysis, Volume 146, 2025, 107956, ISSN 0889-1575

Full text: https://doi.org/10.1016/j.jfca.2025.107956