A new red leaf lettuce (Lactuca sativa L.) cultivar, “Jangsu” which has late bolting and good red expression leaf color was developed from a cross of “Yeolpungcheokchima” (late bolting and high yield) and “Seoulyakchima” (dark red color). The selection and breeding of advanced lines were done by pedigree method during 2000-2004. The advanced lines were evaluated for yield and adaptability in Korea (Gangwon, Kyunggi, Chungbuk, Kyungnam, Jeonnam, Jeonbuk, and Jeju) from 2005 to 2006. The “Jangsu” has gray seed color and elliptic thick leaves. Compared to “Yeolpungcheokchima”, marketable yield of “Jangsu” was lower by 10% (at 469 g per plant), but with particularly improved good expression of red leaf color in high temperature cultivation in the field. The shelf-life of “Jangsu” was three weeks longer than “Yeolpungcheokchima” at 4℃. The amount of bitter sesquiterpene lactones (BSL) and sugar content of “Jangsu” were similar with “Yeolpungcheokchima” at 46 ㎍/g and 4.8 brix, respectively, but taste is better, more crispy, and sweeter than “Yeolpungcheokchima”.

A new high yield and storability lettuce (Lactuca sativa L.) cultivar Jeokdan was developed from a cross NAAES DL14 (late bolting and high yield) and NAAES DL 108 (late bolting and disease resistance) in 1997. We selected desired charac-2003 year, and we