Characterization of Leaf Cuticular Wax Composition on a Genetically Diverse Collection of Lettuce (Lactuca sativa L.) using a Linear Mixed Model

Abstract

Lettuce is an important leafy vegetable in the American diet and recent studies havehighlighted the potential role of its leaf cuticle. The leaf cuticle aids in adapting to water stress and reducing pathogen attachment during post-harvest storage. However, there is a limited understanding of the composition of leaf cuticular waxes in diverse lettuce cultivars. This research presents the first field study of lettuce waxes and their chemical analysis in 12 different genotypes at five different stages during the pre-flowering stage, in response to outdoor environmental changes. The data was collected by the high-throughput phenotyping (HTP) approaches at the University of Arizona Maricopa Agricultural Center from 2019 to 2020. A linear mixed model (LMM) was used to describe lettuce wax compound variations across 12 genotypes under different irrigation treatments, accounting for the differences in the planting arrangement. Results demonstrate a high level of phenotypic diversity in cuticular wax chemical phenotypes in 12 diverse lettuce cultivars, highlighting the significant potential for genetic selection in this trait. This study provides a foundation for future research to explore the genetic involvement in wax synthesis and improve lettuce germplasm for environmental stress tolerance, production efficiency, and food safety.