Genetic variation in response to N, P, or K deprivation in baby leaf lettuce

Authors: Simko, Ivan

Submitted to: Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2020
Publication Date: 3/3/2020
Citation: Simko, I. 2020. Genetic variation in response to N, P, or K deprivation in baby leaf lettuce. Horticulturae. 6(1):15. https://doi.org/10.3390/horticulturae6010015.
DOI: https://doi.org/10.3390/horticulturae6010015

Interpretive Summary: Baby leaf lettuce is the primary component of spring mix salads that are popular type in packaged salads. Lettuce for baby leaf production is harvested approximately 30 days after planting when the first four true leaves reach the length of about 5–13 cm. Little is known about response of baby leaf lettuce to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Eight lettuce accessions were subjected to five fertilization treatments to investigate genetic differences in reaction to N, P and K fertilization. Potassium deprivation had no obvious effect on plant weight or composition apart from substantially decreased potassium content. Nitrogen and phosphorus deprivations, however, extensively decreased fresh weight and affected plant composition. Phosphorus and nitrogen deprivation considerably increased anthocyanin content in red colored accessions, but decreased it in dark green colored accessions.

Technical Abstract: Lettuce harvested at baby leaf stage is a popular component of mixed salads in ready to use packages. Little is known, however, about response of baby leaf lettuce to nitrogen (N), phosphorus (P), and potassium (K) fertilization. Eight lettuce accessions were subjected to five fertilization treatments to investigate genetic differences in reaction to N, P and K fertilization. The control treatment provided optimal levels of macronutrients for plant growth, while other treatments deprived plants of either N, P, or K. Potassium deprivation had no obvious effect on plant weight or composition apart from substantially decreased potassium content. Nitrogen and phosphorus deprivations, however, extensively decreased fresh weight and affected plant composition. Phosphorus and nitrogen deprivation considerably increased anthocyanin content in red colored accessions, but decreased it in dark green colored accessions, indicating differences in regulation of anthocyanin biosynthesis. Correlations between fresh weight, chlorophyll, anthocyanin, nitrogen, phosphorus, and potassium contents were substantially affected by selection of datasets used for analyses; some relationships were revealed when analyzed separately on individual treatments, while others were more likely to be detected when analyzed on individual accessions. 'ABS and 2'REL parameters described in this study are suitable for detecting over- and under-performing accessions. 'ABS identifies absolute Lb-fold change in performance of an accession in a treatment as compared to its performance in control conditions. 2'REL parameter shows relative Lb-fold change for an accession as compared to overall mean of 'ABS values of all accessions tested in control and the treatment conditions.