A spectroscopy approach to the study of virus infection in the endophytic fungus Epichloë festucae

Table 2 PLS1 method to estimate the correct classification (%) of virus infection in E.festucae isolates

Data pre-treatment	2006 (n= 11)			2008 (n= 31)			2006 + 2008 (n= 42)
	F^a	Virus ( n = 6)	No virus ( n = 5)	F^a	Virus ( n = 16)	No virus ( n = 15)	F^a	Virus ( n = 22)	No virus ( n = 20)
Raw	4	100	80	1	75	47	6	73	65
MSC^b	3	100	80	4	81	60	5	77	70
SNV^c	3	100	80	4	81	60	6	82	75
1D^d	2	100	80	1	62	47	5	73	75
MSC^b+1D^d	2	100	80	2	81	67	4	73	75
SNV^c+1D^d	2	100	80	2	81	67	3	86	75
2D^e	4	100	100	1	62	53	4	73	65
MSC^b+2D^e	1	100	100	3	75	60	4	73	55
SNV^c+2D^e	1	100	100	3	75	60	4	82	75

Results of the external validation for individual and combined years (2006 and 2008) using different data pre-treatments. Bold type indicates the best classifications obtained for detection of virus infection
^a Number of PLS factors
^b Multiplicative scatter correction
^c Standard normal variate
^d First derivative
^e Second derivative

ISSN: 1743-422X