Phenotypic characterization and inheritance of enzymatic browning on cut surfaces of stems and leaf ribs of romaine lettuce

Enzymatic browning is a major postharvest quality defect of romaine lettuce (Lactuca sativa L.). This study provides the first analysis relationship between leaf ribs and stems across twelve genotypes (ten cultivars, breeding line, plant introduction). While all samples showed progressive increase in index (BI) decline lightness (L*) hue (h°) during 5 °C storage, differences rate development were observed among genotypes. The most intensive was mainly around vascular bundles dispersed along rim area stems. Browning on cut surfaces correlated with ribs, Pearson correlation coefficients 0.886 for BI, 0.891 L* 0.866 h°. These results that degree can be predicted by High genetic similarity found four cultivars limited (Darkland, Parris Island Cos, Green Towers, Hearts Delight) also severe (King Henry Tall Guzmaine). highest broad-sense heritability (H2) both trials (July November 2018) 0.88 0.92 stem rib browning, respectively. method based used to simplify phenotypic evaluation decipher genetics accelerate browning-resistant cultivars.