CONSTRUCTION OF A LYCHEE GENETIC LINKAGE MAP BASED ON RAPD MARKERS

Maguili (Litchi chinensis ‘Maguili’) and Jiaohesanyuehong (a stenospermocarpy mutant of Litchi chinensis ‘Sanyuehong’), two highly divergent cultivars of lychee from Guangdong Province, China, were used as parents to develop an F₁ population with 76 individuals.
Based on this population, an analysis of randomly amplified polymorphic DNA (RAPD) was performed to construct a linkage map.
A set of 500 random oligonucleotide primers were screened and 104 primers were selected to generate RAPD markers with DNAs from the 76 F₁ progenies.
Among the 294 loci identified, only 135 loci from Maguili were used to construct a lychee linkage map, since the others deviated from the expected 1:1 segregation.
The resulting linkage map consisted of 107 marker loci linked in 13 groups with four or more loci per group, 12 in triples and 16 in pairs, in total covering a map distance of about 1982.5 cM. This might be the first molecular linkage map reported on lychee (Litchi Sonn.) or even on the family of Sapindaceae.
Further study is underway to locate some important loci, such as fruit maturation period, seed abortion, etc., based on this map.