title: A major QTL introgressed from wild Lycopersicon hirsutum confers chilling tolerance to cultivated tomato (Lycopersicon esculentum).
abstract: Many plants of tropical or subtropical origin, such as tomato, suffer damage under chilling temperatures (under 10 degrees C but above 0 degrees C). An earlier study identified several quantitative trait loci (QTLs) for shoot turgor maintenance (stm) under root chilling in an interspecific backcross population derived from crossing chilling-susceptible cultivated tomato (Lycopersicon esculentum) and chilling-tolerant wild L. hirsutum. The QTL with the greatest phenotypic effect on stm was located in a 28 cM region on chromosome 9 (designated stm 9), and enhanced chilling-tolerance was conferred by the presence of the Lycopersicon hirsutum allele at this QTL. Here, near-isogenic lines (NILs) were used to verify the effect of stm 9, and recombinant sub-NILs were used to fine map its position. Replicated experiments were performed with NILs and sub-NILs in a refrigerated hydroponic tank in the greenhouse. Sub-NIL data was analyzed using least square means separations, marker-genotype mean t-tests, and composite interval mapping. A dominant QTL controlling shoot turgor maintenance under root chilling was confirmed on chromosome 9 using both NILs and sub-NILs. Furthermore, sub-NILs permitted localization of stm 9 to a 2.7 cM interval within the original 28 cM QTL region. If the presence of the L. hirsutum allele at stm 9 also confers chilling-tolerance in L. esculentum plants grown under field conditions, it has the potential to expand the geographic areas in which cultivated tomato can be grown for commercial production.
authors.affiliation: Department of Plant Sciences, University of California-Davis, Davis, CA 95616-8780, USA.
authors.forename: F
authors.initials: F
authors.lastname: John Goodstal
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Kohler
authors.forename: Leslie B
authors.initials: LB
authors.lastname: Randall
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Bloom
authors.forename: Dina A
authors.initials: DA
authors.lastname: St Clair
mesh_terms: D000064:Acclimatization; D001483:Base Sequence; D002874:Chromosome Mapping; D017931:DNA Primers; D018551:Solanum lycopersicum / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D040641:Quantitative Trait Loci; D019657:Solanaceae / Q000235:genetics* / Q000502:physiology
chemical_list: D017931:DNA Primers