Abstract

The commercial value of vegetable seeds has increased during the last decades, which has turned seed production into a specialized horticultural activity. Soilless production has been adopted by some seed producers mainly because of sanitary reasons. An additional advantage of soilless culture would be the possibility of managing plant nutrition with the objective of producing more vigorous seeds. However, there is a lack of knowledge about the effects of specific nutritional changes on seed quality attributes, such as vigor or longevity. In the present study, the effect of N supply during growth of the mother plant on quality parameters in lettuce seeds was evaluated. Two experiments in consecutive seasons were established in a greenhouse located under Mediterranean climate conditions in Santiago, Chile. Plants were subjected to N concentrations ranging from 1 to 30 mM. At harvest, seed production (number of seeds per inflorescence and seed weight), seed germination, vigor and longevity were evaluated. Results indicate that seed production is reduced at N concentrations higher than 10 mM, while seed quality start decreasing at N concentrations higher than 5 mM. No differences were observed in seed productivity between 1 and 5 mM, but seed longevity was improved when produced under 5 mM. Seed light requirement for germination decreases with increasing N supply, however this positive effect coupled with a reduction in germination speed and longevity.