GENETIC-LINKAGE OF RANDOMLY AMPLIFIED POLYMORPHIC DNA (RAPD) MARKERS IN SWEET-POTATO

RAPD marker analyses were completed on parents and progeny of two swee tpotato [Ipomoea batatas (L.) Lam.] crosses to determine the feasibili ty of genetic linkage map construction. A total of 100 primers was tes ted and 96 produced amplified genomic DNA fragments. The average numbe r of polymorphisms per primer was 0.69. A total of 134 polyphorphic ma rkers was observed and 74 (60%) segregated 1 band present : 1 band abs ent as needed for use in genetic linkage mapping of polyploids. The 60 % of RAPD markers that segregated 1 : 1 shows that genetic linkage map ping of the hexaploid sweetpotato by RAPD marker analysis is feasible. Linkage was determined for all markers that segregated 1 : 1 and five pairs of linked markers were found. These were the first linked molec ular markers found in sweetpotato and they show that construction of a genetic linkage map is feasible. A genetic linkage map will be a valu able tool to assist in genetic improvements.