GENETIC AND PHYSICAL MAPPING OF THE LATERAL SUPPRESSOR (LS) LOCUS IN TOMATO

Tomato plants homozygous for the recessive lateral suppressor (ls) mut ation show a number of phenotypic abnormalities among which the lack o f lateral meristem initiation during vegetative growth and the absence of petals on the flower are the most prominent. As a first step towar ds the isolation of the Ls gene by means of map-based cloning, we have determined its position on the restriction fragment length polymorphi sm (RFLP) map of tomato. RFLP analysis of 527 F2 plants segregating fo r the ls allele allowed us to define an interval of 0.8 cM in which th e Ls gene is located. Analysis of the physical distance between the tw o flanking RFLP markers by pulsed field gel electrophoresis revealed t hat they lie no further than 375 kb apart. Knowledge of the physical d istance together with the availability of a tomato yeast artificial ch romosome (YAC) library, makes it feasible to isolate the Ls gene by a map-based cloning approach.