Construction of a high density molecular linkage map for lychee based on AFLP and RAPD markers

A high density molecular genetic linkage map of lychee was constructed with AFLP and RAPD molecular markers, based on 73 individuals of a 'Maguili× Jiaohesanyuehong' F1 population. The parents of the population were highly divergent because the female parent was an extremely late ripening cultivar and the male parent is a stenospermocarpy mutant of a very early maturation cultivar 'Sanyuehong'. According to the linkage analysis by Joinmap 3.0 software, the resulting genetic map formed 16 linkage groups which involved 312 markers (169 AFLP and 143 RAPD markers), covered a total genetic distance of 1040.43 cM and had an average interval of 3.51 cM with 19.5 markers per linkage group. The largest linkage group contained 120 markers and covered 124.8 cM. This map is the highest density molecular linkage map in lychee constructed so far and is much better than the one we constructed in 2003. The new map provides a good foundation for QTL location or molecular marker-assisted breeding.