Location: Crop Improvement and Protection ResearchTitle: Phenotypic and genetic characterization of stem and rib browning in romaine lettuce
|PENG, HUI - University Of California|
|Luo, Yaguang - Sunny|
|TENG, ZI - University Of Maryland|
|BORNHORST, ELLEN - Oak Ridge Institute For Science And Education (ORISE)|
Submitted to: American Society of Horticulture Science Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/10/2021
Publication Date: 8/7/2021
Citation: Peng, H., Luo, Y., Teng, Z., Zhou, B., Bornhorst, E.R., Fonseca, J.M., Simko, I. 2021. Phenotypic and genetic characterization of stem and rib browning in romaine lettuce. American Society for Horticultural Science Annual Conference, August 5-9, 2021, Denver, Colorado.
Technical Abstract: Lettuce (Lactuca sativa) is one of the most important leafy vegetables but highly perishable. A major postharvest defect is the browning occurring on both cut leaves and stems of packaged lettuce, which leads to a considerable waste of food and economic loss. This study aimed to evaluate browning potential in stems and leaves of romaine lettuce with twelve cultivars and breeding lines. While all samples showed a progressive increase in browning index (BI) and decline in lightness (L*) and hue (h°) during 5 °C storage, significant differences (p < 0.01) in the rate of browning development were observed among cultivars. The highest browning intensity was observed in cultivar King Henry, while the lowest one was found in cultivar Hearts Delight. On the stem samples, the area around the vascular bundles dispersed along the rim region displayed the most intensive browning. Stem browning was significantly (p < 0.001) correlated with rib browning, as indicated by the Pearson correlation coefficients of 0.886 for BI, 0.891 for L*, and 0.866 for h°. These results suggested that the degree of browning in the stems can be used to predict browning in leaf ribs. Four cultivars with limited browning (Darkland, Parris Island Cos, Green Towers, and Hearts Delight) displayed relatively close genetic relationship and two cultivars with severe browning (King Henry and Tall Guzmaine) also had high genetic similarity. The highest broad-sense heritability (H2) of stem and rib browning in both trials (July and November 2018) was 0.88 and 0.92, respectively. The intensity of stem browning can be used to screen lettuce cultivars and to decipher the genetics of lettuce browning to accelerate the breeding of browning resistant cultivars.