title: RFLP linkage analysis of the Cf-4 and Cf-9 genes for resistance toCladosporium fulvum in tomato.
abstract: Four different populations segregating for one of the two closely linked (possibly allelic) tomato disease resistance genes to the fungusCladosporium fulvum,Cf-4 andCf-9, were generated and analysed for recombination frequencies between theCf-genes and restriction fragment length polymorphism (RFLP) loci. The population consisting of F2 progeny from the interspecific crossLycopersicon esculentum carryingCf-9 ×L. pennellii was identified as the most useful for RFLP mapping of theCf-4/9 locus and an RFLP map around this locus was constructed mainly using this population. The two closest markers identified were CP46, 2.6 cM distal, and a group of 11 markers including TG236, 3.7 cM proximal toCf-4/9. A polymerase chain reaction (PCR)-based procedure for the rapid identification of recombination events between these two markers was developed. The regions of foreign DNA introgression surroundingCf-4 andCf-9 in near-isogenic lines were delimited.
authors.affiliation: Sainsbury Laboratory, John Innes Centre for Plant Science Research, Colney Lane, NR4 7UH, Norwich, England, UK.
authors.forename: P J
authors.initials: PJ
authors.lastname: Balint-Kurti
authors.forename: M S
authors.initials: MS
authors.lastname: Dixon
authors.forename: D A
authors.initials: DA
authors.lastname: Jones
authors.forename: K A
authors.initials: KA
authors.lastname: Norcott
authors.forename: J D
authors.initials: JD
authors.lastname: Jones