There are several CQ-resistant lab strains in widespread use, but DD2 is perhaps the most common. This is, for example, the strain used in the HB3xDD2 genetic cross, see https://www.malariagen.net/projects/parasite/pf-crosses, which was performed in an attempt to map the genetics of CQ resistance by crossing a sensitive strain with a resistant one (http://www.ncbi.nlm.nih.gov/pubmed?term=1970614).
Regarding the number of publications, W2, isolated in 1982 by Oduala, is the first (285 papers). Dd2 isolated from south east asia and cloned in 1990 by Dolan was cited in 196 papers. see http://www.ncbi.nlm.nih.gov/pubmed/25116585.
#catherin #stephen thank you for your valuable suggestion ,Dd2 is multiple drug resistant strain and intermediate for chloroquine is it fine to work with such strain taking chloroquine resistant work concept.??