title: Evaluation of lettuce germplasm resistance to gray mold disease for organic cultivations.
abstract: This study was conducted to evaluate the resistance of 212 accessions of lettuce germplasm to gray mold disease caused by Botrytis cinerea. The lettuce germplasm were composed of five species: Lactuca sativa (193 accessions), L. sativa var. longifolia (2 accessions), L. sativa var. crispa (2 accessions), L. saligna (2 accessions), and L. serriola (1 accession); majority of these originated from Korea, Netherlands, USA, Russia, and Bulgaria. After 35 days of spray inoculation with conidial suspension (3×10(7) conidia/ml) of B. cinerea on the surface of lettuce leaves, tested lettuce germplasm showed severe symptoms of gray mold disease. There were 208 susceptible accessions to B. cinerea counted with 100% of disease incidence and four resistant accessions, IT908801, K000598, K000599, and K021055. Two moderately resistant accessions of L. sativa, K021055 and IT908801, showed 20% of disease incidence of gray mold disease at 45 days after inoculation; and two accessions of L. saligna, K000598 and K000599, which are wild relatives of lettuce germplasm with loose-leaf type, showed complete resistance to B. cinerea. These four accessions are candidates for breeding lettuce cultivars resistant to gray mold disease.
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, RDA, Suwon 441-707, Korea.
authors.forename: Chang Ki
authors.initials: CK
authors.lastname: Shim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, RDA, Suwon 441-707, Korea.
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, RDA, Suwon 441-707, Korea.
authors.forename: Yong Ki
authors.initials: YK
authors.lastname: Kim
authors.affiliation: Organic Agriculture Division, National Academy of Agricultural Science, RDA, Suwon 441-707, Korea.
authors.forename: Hyeong Jin
authors.initials: HJ
authors.lastname: Jee
keywords: Botrytis cinerea; Lactuca saligna L.; Lactuca sativa L.; genetic resources; tolerance