Skip to main content Skip to navigation


A linkage map has previously been produced at WHRI based on F5 Saladin x Iceberg recombinant inbred lines (RILs) using radioactive markers.
This intra-specific cross is potentially of high importance for crop breeding programmes as it combines two lettuce cultivars, compared to other linkage maps based on crosses of a cultivar with a wild relative. However, the use of two cultivars generally results in reduced levels of polymorphism.
An F7 population has been produced from 130 of the most informative RILs that represent the major recombination events found within the population via single seed descent. The production of a linkage map from this population would be more advantageous due to increased homozygosity within the genotypes.
A selection of 94 of the most informative RILs from the F7 population has been selected for analysis. However, the selection at F7 to maximise number of recombination events could result in a bias throughout the research. This will be verified by comparing the loci segregation distortion between the F5 and F7 population.
A previous Defra/HortLINK Project ‘Improving the quality and shelf-life of cut salad products has shown significant variation between the mapping parents for both browning and pinking. Several breeding companies have expressed an interest in the genetic analyses for discolouration of this population.
See more information:



Mapping Parents


WHRI mapping parents - iceberg x saladin