Fig. 3. Principal components (PC) analysis to compare presence of terminal restriction fragments (T-RFs) in corn rootworm (CRW) transgenic corn engineered to express Bacillus thuringiensis toxin (Bt), the non-transgenic isoline (NoBt), and the non-transgenic isoline with tefluthrin (NoBt + I) in 2001 and 2002 after digestion of polymerase chain reaction (PCR) products with (a) HhaI, (b) MspI, and (c) RsaI. Bulk and rhizosphere samples were pooled for this analysis.