Struggling for space in giant hothouses at the Guandong Academy of Agricultural Sciences are 21lb (9.5kg) tomatoes and enormous watermelons.
Researchers fired off a batch of 2,000 seeds into space in 2006 on the Shijian 8 satellite.
After germination the best specimens were selected for further breeding.
Researcher Lo Zhigang said: "Conventional agricultural development has taken us as far as we can go and demand for food from a growing population is endless.
"Space seeds offer the opportunity to grow fruit and vegetables bigger and faster."
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How sending seeds into space produces such enormous fruit is yet not fully understood, but it is thought cosmic radiation, micro-gravity and magnetic fields may play a part.