Abstract: A F2 population including 136 individuals derived from the crossing of non-lateral branch line 419（P1）and branch line SB-2（P2），using this F2 population as materials to research on non-lateral branch（nlb）gene mapping of cucumber. We found that F2 population may be divided into lateral branch
individuals and none lateral branch individuals by field investigation and genetic analysis，and their proportion fit for 3︰1. Constructing none branch and branch gene pools by taking bulked segregant analysis（BSA）which select 10 individuals from F2 non-branch population and branch population
randomly and mix their DNA respectively. We found 9 simple sequence repeat（SSR）markers which have polymorphism between two gene pools was linked to nlb gene. The F2 population was used on further verification and found molecular marker SSR19673 which is closer to nlb gene with genetic distance 15.9 cM through analysis of software MAPMAKER 3.0，therefore，nlb gene was mapped on the first chromosome of cucumber.

Key words: cucumber, nlb gene, gene mapping, SSR marker