Abstract: Bemisia tabaci biotype B has been an invasive agricultural pest worldwide during the past two decades. Compared with the biotype B, biotype Q is a new invasive biotype. However, biotype Q has invaded into numerous countries and caused severe losses. The genetic structure of biotype B and biotype Q was analyzed using random amplified polymorphic DNA （RAPD） markers here. The results showed that:（1）the specific amplified patterns using the primer H16 could distinguish biotype B populations from biotype Q populations and non-B/Q biotype population in Zhejiang province;（2）the genetic diversity of biotype Q was higher than that of biotype B;（3）biotype Q more likely originated from Iberian peninsula than from Middle Eastern regions. Our results also suggest that RAPD markers seem to be unsuitable to be used in analysis of the relationships of different biotypes, though they could be used to distinguish the different biotypes.

Key words: Bemisia tabaci biotype B, Bemisia tabaci biotype Q, genetic structure, RAPD