Loading...Resilient cabbage varieties like kale, head cabbage, and brussels sprouts appear well-suited to the climate of Northwestern Europe. However, the journey of many cabbage species from their wild ancestors, which were originally found along the North Sea coast, to the cultivated forms we recognise today has been quite extensive.
This lengthy evolution has been highlighted in a comprehensive study conducted by a team of Dutch scientists. The research revealed that cabbage (Brassica oleracea) was domesticated independently in multiple regions, resulting in a diverse range of crops including tuber-producing varieties (like swedes), flowering types (like cauliflower and broccoli), and compact head cabbages.
“The study demonstrates the relative ‘ease’ with which cabbage can be domesticated, as evidenced by its ability to independently develop edible flowers in different regions,” says Guusje Bonnema, a breeding researcher at Wageningen University, who led the study.
Selection and the tin traders
Along with her team, Guusje compared the DNA of modern hybrid cabbage varieties with a diverse range of landraces (a landrace is generally defined as a cultivated, genetically heterogeneous, localised variety that are adapted to the soil and climatic conditions of its locality and traditional managemnt practices) obtained from gene banks worldwide.
By analyzing DNA fragments or ‘fingerprints’ they were able to trace the genetic relationships between different cabbage plants. So what did they find?
Early European selection focused on wild varieties with abundant and varied leaves, laying the foundation for today’s curly kale and palm cabbage, expalins Guusje. “From that breeding led to Asia, where additional traits got combined with the Western European kale varieties.” This has raised an intriguing question: How did these traits make their way to Asia?
The tin trade is believed to have played a significant role. Tin mining activities along the British and French coasts around 2500BC likely facilitated the transport of seeds to the Middle East aboard ships. “We suspect that these early cabbage varieties contributed to the development of head cabbages and cauliflower,” explains Guusje. “These cultivated varieties were subsequently crossbred with wild relatives in Asia, before eventually making their way back to Western Europe where they underwent further refinement.”
Climate-Resilient
Research has provided valuable insights into the genetic diversity stored in gene banks, which is crucial for breeders because it enables them to better understand the extent of variation among cabbage varieties and their genetic relationships. Breeders are currently focused on enhancing the resilience of crops to withstand climate challenges.
“The abundance of options available for breeding resilient cabbage varieties, highlights the wealth of genetic diversity within the cabbage family”, says Jorrit Lind, a brassica breeder at Bejo Zaden, who is actively involved in this endeavor. Farmers seek robust varieties that can thrive in extreme conditions for extended periods. While this new knowledge doesn’t offer immediate access to drought-resistant parent plants from the Middle East, the research is vital in guiding our breeding efforts.
“The varieties historically cultivated in regions like Turkey, Syria, and Lebanon are no longer suited for modern agricultural practices,” he continues. “Therefore, our breeding work involves selecting traits from the genetic pool of our northwestern european varieties and their relatives in the Middle East region.”
Elaborate Trait
Jorrit believes that there is room for advancement in pre-breeding; a fundamental aspect of breeding, through the integration of traits from wild relatives or the exchange of characteristics among closely related cabbage types.
“However, it is important not to jump ahead of ourselves,” he adds. “Even with the assistance of innovative techniques like gene editing – if permitted for use – modifying climate resilience is not as simple as toggling a few genes on or off. Climate resilience is a multifaceted trait influenced by numerous genes. Yet, with a deeper understanding of genetic relationships, my optimism for future advancements has only grown.”