Assessment of mineral nutrient concentrations of lettuce in response to cultivar selection and fertilization in greenhouse production

ABSTRACT

Mineral nutrient contents in vegetable-based foods are a concern in human diets, and depleted soil fertility and high-yielding cultivars are associated with low nutrient contents. This study explored if mineral nutrient concentrations of lettuce (Lactuca sativa L.) can be increased though selection of cultivars and nutritional regimes in greenhouse production. Cultivars including butterhead, romaine, and loose-leaf phenotypes of heritage and modern origins were studied. Hoagland solution, a commercial inorganic fertilizer, and a commercial organic fertilizer were the nutrient regimes. Heritage cultivars had about 10% higher phosphorus, potassium, calcium, magnesium, and zinc (P, K, Ca, Mg, and Zn) concentrations than modern cultivars. Differences in elemental concentrations occurred among phenotypes and nutritional regimes but with no consistent trend among elements for phenotypes or regimes. Some cultivars had twice the concentrations of nutrients of other cultivars. This work suggests that cultivars can be selected for production of mineral nutrient-rich lettuce.

KEYWORDS:

• Macronutrients
• micronutrients
• nutrient accumulation
• fertilizer regimes
• Lactuca sativa

Acknowledgements

This material is based upon work supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, the Massachusetts Agricultural Experiment Station, and the Stockbridge School of Agriculture under Project numbers MA 00469, MA00963 and MAS00981 and is paper number 3499 in the Experiment Station journal series.