Bioseedling: a chain approach to the production of healthier seeds and seedlings of Lamb’s lettuceValerianella locusta

Abstract

The project BIOSEEDLING "Robust planting material from seeds to young plants-an implementation oriented chain approach" aims to find improved production procedures for vegetable seedlings of lamb's lettuce. First, the production of lamb's lettuce seeds of a professional seed producer was analyzed and the effect of harvest time and seed size on the germination and disease rate in the seeds was studied. Then, using seeds naturally infected by Peronospora valerianellae and Acidovorax valerianellae, several seed disinfection methods were compared: aerated steam, hot water, sodium hypochlorite, ethanol, Calcium hydroxide, and compost pellet. After testing methods for the identification of the seed pathogens and the quantification of the infection, an assessment on how the different treatments reduce the pathogens and whether they alter the seeds germination capacity was made. In a third step, substrates suppressive of the soil borne pathogens Rhizoctonia solanii and Pythium ultimum were developed and several plant protection agents were tested against Peronospora valerianellae. Furthermore, the effect of night interruption on the sporulation of lamb's lettuce downy mildew (Peronospora valerianellae) using periods of lighting in the red and blue regions was tested. The aim is to combine the best methods resulting from all the experiments cited above in a future experiment and compare them to the standard methods in an on-farm experiment.