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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #320816
Title: Breeding lettuce for improved fresh-cut processing

Author
item Hayes, Ryan
item Simko, Ivan

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2016
Publication Date: 12/12/2016
Citation: Hayes, R.J., Simko, I. 2016. Breeding lettuce for improved fresh-cut processing. Acta Horticulturae. 1141:65-76. doi: 10.17660/ActaHortic.2016.1141.7.

Interpretive Summary: Lettuce is a widely grown vegetable that is used to make packaged salads sold at retail supermarkets. These salads are popular with consumers due to their convenience. Production and processing of fresh-cut lettuce is continually changing, offering more products and becoming more efficient. Breeding new lettuce cultivars that have specialized traits for this market can offer further improvements. However, development of these cultivars has received attention only within the last decade. Improvements to head shape and color may increase yield, quality, and production efficiency. Defects occurring inside the lettuce head (internal defects) are problematic, since they are not discovered until the crop is processed into salad. Crops must meet high stringencies for internal defects and cultivars specialized for fresh-cut often need high levels of resistance to these problems. After processing, exposure of the cut surfaces to air can result in pink or brown coloration. Modified atmosphere packages that are filled with nitrogen to displace the air are often used to reduce browning or pinking. Development of cultivars that do not develop these colors after cutting could minimize or eliminate the need for modified atmosphere packages. New cultivars with longer shelf life could reduce waste and increase the distribution system’s efficiency. The nutritional content of fresh-cut lettuce can decline after processing. Research that addresses this issue may improve the popularity of fresh-cut lettuce. Lettuce and its wild relatives possess genes for improved plant morphology, quality and resistance to abiotic stresses. These genes can be bred into improved cultivars. Genetic analysis has determined the inheritance of many traits useful for the fresh-cut industry. This knowledge should be used to devise molecular breeding methods that can accelerate development of new cultivars. These approaches are particularly useful for improving post-harvest traits. Testing methods for post-harvest traits is often laborious, destructive, requires specialized equipment, and typically needs large numbers of plants.

Technical Abstract: Lettuce is a widely grown vegetable that is used to make fresh-cut salads, which are popular with consumers due to their convenience. Production and processing of fresh-cut lettuce is continually evolving, offering more products and becoming more efficient. Breeding new lettuce cultivars specialized for this market can offer further improvements, but has received attention only within the last decade. Improvements to plant morphology can increase yield, quality, and production efficiency. Crops must meet high stringencies for internal defects and cultivars specialized for fresh-cut often need enhanced levels of resistance to these problems. Modified atmosphere packages are used to reduce browning or pinking of cut surfaces. Development of cultivars that do not discolor could minimize or eliminate the need for modified atmosphere packages. New cultivars with longer shelf life could reduce waste and increase the distribution system’s efficiency. The nutritional content of fresh-cut lettuce can decline after processing. Research that addresses this issue may improve the popularity of fresh-cut lettuce. Lettuce and its wild relatives have genetic variation for plant morphology, quality and resistance to abiotic stresses that can be used to breed improved lettuce cultivars. Quantitative trait loci mapping has determined the inheritance of many traits useful for the fresh-cut industry. This knowledge should be used to devise molecular breeding methods that accelerate cultivar development. These approaches are particularly useful for improving post-harvest traits, since phenotypic assays for these traits are often laborious, destructive, require specialized equipment, and typically test large numbers of plants.