Genetic discoveries explain how Chinese barley adapts for double cropping

A research team led by Ping Yang at the Chinese Academy of Agricultural Sciences and scientists at the IPK Leibniz Institute identified specific gene combinations that allow barley to mature quickly enough for double cropping in China.

In regions of central and eastern China, farmers grow barley in the autumn and harvest it in late spring before planting a summer crop like rice.

For this system to work, barley must reach maturity rapidly to avoid heat and rain while leaving enough time for the next crop. The researchers analyzed 505 Chinese barley varieties and 27 introduced reference lines, tracing genetic changes since the 1940s. They discovered that a specific variant of the PHYTOCHROME C (PhyC) gene, which acts as a light receptor, works in tandem with a VERNALIZATION 1 (VRN1) gene to accelerate maturity.

While the PhyC variant can reduce biomass if paired with spring barley genes, it maintains grain yield when paired with winter barley genes. This specific combination has become common in Chinese autumn-sown varieties, appearing in more than 60% of modern varieties examined since the 1990s. To confirm these findings, the team used base editing to recreate the genetic changes in barley and wheat, which both showed earlier development.

However, the same change caused rice plants to flower later because rice responds differently to light signals than barley and wheat. The researchers say this knowledge helps breeders tailor flowering times to specific growing conditions, though they note that further field trials are needed to see how these genes perform in different regions.