CONSTRUCTION OF A GENETIC-LINKAGE MAP IN CELERY USING DNA-BASED MARKERS

A F-2 population of two celery cultivated types (Apium graveolens L. v ar. rapaceum and A. graveolens L. var. secalinum) was used to construc t a linkage map consisting of 29 RFLP (restriction fragment length pol ymorphism), 100 RAPD (random amplified polymorphic DNA), four isozyme, one disease resistance, and one growth habit markers. The map contain s 11 major groups and 9 small groups and has a total length of 803 cM with an average distance of 6.4 cM between two adjacent loci. Ten perc ent of the RAPDs segregated as codominant markers and their allelic ho mologies were tested by Southern hybridization. One-quarter of the dom inant RAPDs were linked in repulsion phase, whereas the majority of th em were linked to either codominant or dominant markers in coupling ph ase. About 10% of the markers showed significant segregation distortio n. The detectable level of duplications in the celery genome was relat ively low.