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Ryan J. Hayes and Yong-Biao Liu

Packaged salad-cut lettuce for food service and salad mixes is an increasingly important component of the lettuce industry ( Glaser et al., 2001 ). Lettuce is highly perishable, and the cutting required in processing further shortens its shelf

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Theekshana C. Jayalath, George E. Boyhan, Elizabeth L. Little, Robert I. Tate and Suzanne O’Connell

Lettuce ( Lactuca sativa L.) is a popular, cool-season vegetable with a total U.S. production value of nearly $1.5 billion in 2013 ( AgMRC, 2015 ). From 2005 to 2011, the amount of U.S. farmland allocated to the organic lettuce production increased

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Martin P.N. Gent

Several studies have shown environment and nutrition have effects on growth of lettuce. RGR, the relative increase in weight per day, changes slowly as plants grow in a constant environment. What are the components of plant growth that scale

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Edward J. Ryder

Three chlorophyll deficiency traits in lettuce (Lactuca sativa) are reported. One, chlorophyll deficient-3 (cd-3), is quite yellow in the seedling stage, and controlled by a single recessive allele. Chlorophyll deficient-4 (cd-4) has sectors of yellow-green and green in the true leaves. It is inherited as a single recessive, and may be allelic to chlorophyll deficient-2 (cd-2). Sickly (si) is stunted, yellow, and partially necrotic, and is also controlled by a single allele. Virescent (vi) is epistatic to cd-4 and the latter is partially lethal. Linkage and additional epistatic relations with previously named chlorophyll deficient genes and other traits are discussed.

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Xuetong Fan and Kimberly J.B. Sokorai

radiation is known to effectively eliminate human pathogens such as Escherichia coli O157:H7 on fresh produce ( Niemira and Fan, 2006 ). In 2008, ionizing irradiation was approved by the U.S. Food and Drug Administration for use on fresh Iceberg lettuce

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Edward J. Ryder, William Waycott and James D. McCreight

supported by a grant from the California Iceberg Lettuce Research Program. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to

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Guangyao Wang, Mathieu Ngouajio, Milton E. McGiffen Jr and Chad M. Hutchinson

vegetable crop rotation in the low desert provides a niche in the cropping cycle that is ideal for a warm season cover crop. Lettuce is planted in the fall (September to October) followed by spring muskmelon in February to March. After muskmelon harvest in

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Yu Sung, D.J. Cantliffe and R.T. Nagata

Lettuce seeds differentially fail to germinate at temperatures above 21C according to genotype. Twenty-one lettuce lines were screened for their ability to germinate at temperatures from 24C to 36C. Four cultivars, `Dark Green Boston', `Valmaine', `Floricos 83', and `PI251245', were selected for this study because of their range of ability to germinate at temperatures above 24C. Seeds of the four cultivars were collected from mother plants grown in growth chambers at 20/10C(day/night temperature), 25/15C, 30/20C and 35/25C. Seeds were germinated on a thermogradient table from 24C to 36C under light (12 h). Seeds from `Floricos 83' produced above 30C had higher germination percentage at 33C and 36C than those produced below 30C temperatures. At 30C germination temperature seeds of `Valmaine' produced above 30C had 98% germination compared to 45% of those produced below 30C. `Dark Green Boston' seeds produced at 35C had higher germination percentage(70%) at 30C than those produced at other temperatures. Seeds collected from the mother plant grown above 30C day temperatures had greater germination than those grown below 30C.

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Tongyin Li, Guihong Bi, Judson LeCompte, T. Casey Barickman and Bill B. Evans

summer in New Anchialos, a coastal area of eastern central Greece. Shade levels of 30% to 47% increased yield of lettuce cultivars (Green Mignonette, Salinas, and Amaral 400), WR-55 Days chinese cabbage ( Brassica rapa ), and Tastie Hybrid head cabbage

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Miguel Urrestarazu, Cinthia Nájera and María del Mar Gea

several authors ( Li et al., 2013 ). Johkan et al. (2012) suggest that high-intensity green LED light promotes lettuce growth, and in particular, short-wavelength green light (510 nm) is available for active plant growth. On the other hand, the use of