A hemp landrace from southern Yunnan was selected to study the chemotype and genotype of two main cannabinoids (tetrahydrocannabinol,THC;cannabidiol,CBD) by chemical test and gene cloning,respectively.The results are:(1)Chemical test revealed that all 21 plants contained THC,and the THC content ranged from 0.07% to 1.35%.In this population,9 plants contained THC alone,5 plants contained THC and trace CBD,and the other 9 plants included both THC and CBD,while the CBD content ranged from 0 to 0.58%.(2)Accordingly to the content ratio of CBD/THC,only drug-type and intermediate-type were existed in the landrace.There was also a positive correlation between THC and CBD contents in the plants of intermediate-type.(3)Gene amplification and sequence alignment showed 5 base variations and 2 base variations in THCA synthase genes and CBDA synthase genes,respectively,and the variations had no direct relations with the contents of THC and CBD.(4)The genotype completely matched with chemotype in 21 plants,and the two synthase genes can be made as molecular marker to identified chemotype in a single plant.