Table 5.

Pearson's correlation matrix showing the relationship between MPN and qPCR approaches for estimation of R. leguminosarum numbers in soils exposed to increasing levels of zinc contamination^a

Predictor used	Correlation between estimates
	Woburn				Watlington
	MPN, bv. trifolii	MPN, bv. viciae	16S rRNA gene	nodD trifolii	MPN, bv. trifolii	16S rRNA gene	nodD trifolii
MPN, bv. viciae	0.734***
16S rRNA gene	0.692**	0.817***			0.637*
nodD trifolii	0.743**	0.698**	0.594*		0.926***	0.785**
nodD viciae	0.871***	0.924***	0.765***	0.687**	0.776**	0.759**	0.770**

^aSignificant correlations are shown as follows: ***, P < 0.001; **, P < 0.001; *, P < 0.05.