The response of lettuce (Lactuca sativa L.) accessions to postemergence herbicides

Abstract

This study evaluated the phytotoxic response of thirteen lettuce accessions, including commercial cultivars and experimental breeding lines from the University of Florida’s Breeding Program (UF/IFAS), to twelve postemergence (POST) herbicides under controlled greenhouse conditions. The experiment was conducted at the Everglades Research and Education Center (EREC), University of Florida, using a completely randomized design with a factorial arrangement. Visual injury ratings and relative dry biomass were assessed 28 days after treatment. Significant differences were detected among genotypes, herbicides, and the genotype × herbicide interaction. The herbicides fomesafen, glufosinate, glyphosate, linuron, mesotrione, prometryn, and topramezone caused severe injury across all genotypes, indicating a lack of selectivity. In contrast, acetolactate synthase (ALS) inhibitors, particularly flumetsulam, resulted in minimal damage in several genotypes. Principal component analysis (PCA) identified distinct sensitivity groupings, highlighting Batavia Reine de Glaces, PI 491224, 10221, 49017, and H1098 as promising candidates for breeding programs due to their tolerance profiles. Overall, these findings provide valuable insights for the development of herbicide-tolerant lettuce cultivars and support sustainable weed management strategies.