Seed Priming Applied to Onion-Like Crops: State of the Art and Open Questions

Cultivation of onion and onion-like crops has become a challenge in the context of climate change and innovative solutions are needed to support breeders as well as farmers, starting from the crucial issues of seed quality. Seed priming is routinely used to enhance germination performance and seedling resilience. Although common for radish, tomato, carrot or head cabbage seeds, the technique has been less popular for onion-like crops. This review provides a state-of-the-art picture of the scientific and technological advances that have so far contributed to enhance seed germination and vigour in onion-like crops. A brief description of the different types of priming approaches is provided whereas attention is focused on the following: (i) the impact of seed priming in terms of improved germination, seedling development and resilience to environmental stresses; (ii) the concept of seed quality hallmarks translated from model plants to the genus Allium; (iii) the drawbacks that currently impair the fully exploitation of seed priming in this specific sector of the agrifood chain.