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ARS Home » Pacific West Area » Salinas, California » Crop Improvement and Protection Research » Research » Publications at this Location » Publication #140336
Title: ROMAINE LETTUCE (LACTUCA SATIVA L.) BREEDING LINES WITH RESISTANCE TO LETTUCE DIEBACK CAUSED BY TOMBUSVIRUSES.

Author
item Grube, Rebecca
item Ryder, Edward

Submitted to: HortScience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2002
Publication Date: N/A
Citation: N/A

Interpretive Summary: The soilborne disease lettuce dieback has been reported with increasing frequency in both California and Arizona lettuce production areas, and is caused by at least two members of the virus family Tombusviridae, lettuce necrotic stunt virus (LNSV) and tomato bushy stunt virus (TBSV). Dieback causes severe stunting and chlorosis, mottling, and necrosis in older leaves, and can cause complete crop loss. Genetic resistance exists in crisphead and leaf lettuce cultivars, but no commercial romaine cultivars are resistant. In this report, we describe three romaine lettuce lines: 01-778M, 01-781M and 01-789M. These lines are dark green, attractive, romaine lettuces with slight blistering. 01-789M has a larger percentage of closed heads than 01-778M and 01-781M, which have an open growth habit with erect leaves that do not tend to curve inwards. The breeding lines were asymptomatic in fields in which commercial romaine cultivars developed symptoms of lettuce dieback.

Technical Abstract: The soilborne disease lettuce dieback is caused by at least two members of the virus family Tombusviridae, lettuce necrotic stunt virus (LNSV) and tomato bushy stunt virus (TBSV). Dieback causes severe stunting and chlorosis, mottling, and necrosis in o older leaves, and can cause complete crop loss. No commercial romaine lettuce cultivars are resistant. In this report, we describe three romaine lettuce breeding lines: 01-778M, 01-781M and 01-789M. These lines are dark green, attractive, romaine lettuces with slight blistering. 01-789M has a larger percentage of closed heads than 01-778M and 01-781M, which have an open growth habit with erect leaves that do not tend to curve inwards. The lines were asymptomatic in fields in which commercial romaine cultivars developed symptoms of lettuce dieback. The breeding lines were also compared with commercial romaine cultivars in a disease-free planting. Plant heights, head weights, and core lengths of the three breeding lines were not significantly different from all or most cultivars tested. The breeding lines had significantly more leaves than all cultivars. Although readily detached, older leaves of the breeding lines did not snap as crisply from the bases of plants as did those of commercial cultivars, and in summer plantings, the breeding lines exhibited some premature bolting.