Environmental pressures and limited natural resources are forcing agriculture to produce higher yields while using less water and fertilizer. Although lettuce has been extensively bred for taste, texture, and yield, this process has left it vulnerable to nutrient deficiencies. Developing lettuce varieties that require fewer inputs therefore demand crops with greater genetic resilience.

However, the long history of domestication has significantly reduced the genetic diversity present in cultivated lettuce. This loss of diversity restricts the availability of genetic resources for breeding and limits opportunities for crop improvement. Fortunately, several wild relatives of lettuce may help restore this diversity and strengthen crop resilience.

One particularly promising relative is prickly lettuce (Lactuca serriola). While unsuitable for consumption due to its bitter taste and characteristic prickles, it is exceptionally resilient. Unlike cultivated lettuce, prickly lettuce can grow in nutrient-poor soils and survive in harsh, desert-like environments. Transferring these resilience traits into cultivated lettuce could substantially improve its performance under low-input conditions. To achieve this, understanding the genetic basis of stress tolerance in prickly lettuce is essential.

As part of the EU-COUSIN project, research at Wageningen University aims to unravel the genetic mechanisms underlying the robustness of prickly lettuce. The first phase of this work focuses on identifying genetic factors that enable prickly lettuce to perform well under phosphorus-limited conditions. To investigate this, a panel of approximately 150 prickly lettuce genotypes was grown in hydroponic systems with restricted phosphate availability. During the experiment, plants were continuously monitored using the high-throughput phenotyping facilities at NPEC, enabling detailed tracking of plant growth and development. The resulting data are used to identify genotypes that perform well under low-phosphate conditions. These phenotypic observations are subsequently integrated with genomic data through genome-wide association studies to identify genetic markers linked to improved performance under phosphorus limitation. Through this research, we aim to establish the foundation for using wild lettuce genetic resources to enhance the resilience of cultivated lettuce.