Differential accumulation of deoxynivalenol in two winter wheat cultivars varying in FHB phenotype response under field conditions

Figures & data

Fig. 1. Rainfall in May and June of 2007–2009 at Mead, Nebraska, USA where experiments were conducted to determine the phenotypic reaction of three winter wheat cultivars (‘2137’, ‘Harry’ and ‘Jagalene’) to Fusarium head blight and the differential accumulation of deoxynivalenol in two winter wheat cultivars (‘2137’ and ‘Harry’). The white arrow indicates the beginning of anthesis in ‘2137’ and ‘Jagalene’ whereas the black arrow indicates the beginning of anthesis in ‘Harry’.

Table 1.  Weather parameters at Mead, Nebraska, USA where experiments were conducted in 2007–2009 to investigate the accumulation of deoxynivalenol (DON) in two winter wheat cultivars: ‘Harry’ (moderately resistant to Fusarium head blight (FHB), high DON accumulator) and ‘2137’ (susceptible to FHB)

Year	Month	Total rain (mm)^a	Average RH (%)	RH range	Average min temp (°C)	Average max temp (°C)	Average temp (°C)
2007	May	160	68.1	46.3–91.1	12.4	25.0	18.7
	June	40	70.2	43.4–90.6	15.4	28.1	21.8
2008	May	137	65.6	35.5–93.8	8.4	22.2	15.3
	June	234	70.0	48.0–90.9	15.4	28.4	21.9
2009	May	25	58.4	37.7–85.8	9.5	24.5	17.0
	June	107	75.5	40.1–94.8	15.2	27.1	21.1
^aThe 30-year (1981–2010) average rainfall at Mead was 101 mm in May and 105 mm in June (High Plains Regional Climate Center, School of Natural Resources, University of Nebraska-Lincoln, Lincoln, Nebraska, USA).

Table 2.  Fusarium head blight (FHB) index (%) ^a in three winter wheat cultivars subjected to three inoculation treatments (early anthesis, mid anthesis and non-inoculated) in an experiment to determine the phenotypic reaction (moderately resistant or susceptible) of the three cultivars to FHB in 2007 and 2008

		Inoculation treatment and index (%)
Year	Cultivar	Early anthesis	Mid anthesis	Non-inoculated
2007	Harry	19.6 c^b	36.6 b	22.1 b
	2137	44.5 a	55.6 a	41.9 a
	Jagalene	35.0 b	62.5 a	38.8 a
2008	Harry	5.8 b	14.0 c	7.2 b
	2137	18.6 a	31.5 b	18.0 a
	Jagalene	24.4 a	42.8 a	22.5 a
^aIndex was assessed 21 days after inoculation. Index in the non-inoculated treatment was assessed 21 days after the early anthesis inoculation treatment. Each index value is a mean of two planting dates and three replications per cultivar (n = 6).
^bMeans within a column in a year followed by the same letter are not significantly different according to the least significant difference test at P = 0.05.

Table 3.  Plot Fusarium head blight (FHB) index, Fusarium-damaged kernels (FDK), and deoxynivalenol (DON) concentration in two winter wheat cultivars, 2007–2009

Year	Cultivar	Index (%)	FDK (%)	DON (ppm)
2007	Harry	16.7 b^a	19.7 a	1.1 a
	2137	45.7 a	12.7 a	1.5 a
2008	Harry	12.0 a	64.0 a	11.9 a
	2137	19.7 a	46.0 b	9.3 a
2009	Harry	6.5 a	30.4 a	1.7 a
	2137	0.4 a	29.8 a	1.0 a
^aMeans within a column in a year followed by the same letter are not significantly different according to the least significant difference test at P = 0.05.

Fig. 2. Average deoxynivalenol (DON) concentration in grain from tagged spikes in experiments conducted at Mead, Nebraska, USA in 2007–2009 to investigate the accumulation of DON in two winter wheat cultivars: ‘Harry’ (moderately resistant to Fusarium head blight (FHB), high DON accumulator) and ‘2137’ (susceptible to FHB). Spikes were tagged according to severity categories ranging from 0 to 50% in 2007 and 2009 and according to severity categories ranging from 20 to 90% in 2008. Means (bars) with the same letter within a year are not significantly different at P = 0.05 according to the t-test.

Table 4.  Analysis of covariance with cultivar as a categorical factor, deoxynivalenol (DON) as a dependent variable and FHB severity as a covariate. Data were obtained from field experiments conducted at Mead, Nebraska, USA in 2007–2009 to investigate the accumulation of DON in symptomatic spikes tagged in increasing FHB severity categories in two winter wheat cultivars (‘2137’ and ‘Harry’)

		2007		2008		2009
Source of variation	d.f.^a	MS^b	P > F	MS	P > F	MS	P > F
SeverityLinear (SL)^c	1	3.37	0.0001	348.9	0.0021	189.2	0.0001
Cultivar (C)^d	1	61.5	0.0043	1947.6	0.0358	167.8	0.0203
SL x C^e	1	7.7	0.0008	55.5	0.1910	1.5	0.6929
^aDegrees of freedom.
^bMean square.
^cTest for linear effect of severity.
^dThe F-test for comparing cultivar least squares means was based on pooling replication sums of squares with error sums of squares.
^eTest for different cultivar slopes.

Table 5.  Analysis of covariance with year as a categorical factor, deoxynivalenol (DON) as a dependent variable and FHB severity as a covariate. Data were obtained from experiments conducted at Mead, Nebraska, USA in 2007–2009 to investigate the accumulation of DON in symptomatic spikes tagged in increasing FHB severity categories in two winter wheat cultivars (‘2137’ and ‘Harry’)

		Harry		2137
Source of variation	d.f.^a	MS^b	P > F	MS	P > F
SeverityLinear (SL)^c	1	202.9	0.0005	326.2	<0.0001
Year	2	7594.5	<0.0001	3331.1	< 0.0001
SL x Y^d	2	9.2	0.7330	120.3	<0.0001
^aDegrees of freedom.
^bMean square.
^cTest for linear effect of severity.
^dTest for different slopes across years.

Fig. 3. Regression of deoxynivalenol (DON) concentration on Fusarium head blight (FHB) severity by cultivar within year. Data were obtained from experiments conducted at Mead, Nebraska, USA in 2007–2009 to investigate the accumulation of DON in two winter wheat cultivars: ‘Harry’ [moderately resistant to Fusarium head blight (FHB), high DON accumulator] and ‘2137’ (susceptible to FHB).

Fig. 4. Regression of deoxynivalenol (DON) concentration on Fusarium head blight (FHB) severity by year within cultivar. Data were obtained from experiments conducted at Mead, Nebraska, USA in 2007–2009 to investigate the accumulation of DON in two winter wheat cultivars: ‘Harry’ [moderately resistant to Fusarium head blight (FHB), high DON accumulator] and ‘2137’ (susceptible to FHB). Regression equations: ‘Harry’, 2007: Y = 1.13 + 0.07X; R² = 0.55, P = 0.0087; ‘Harry’, 2008: Y = 29.9 + 0.07X; R² = 0.32, P = 0.1092; ‘Harry’, 2009: Y = 5.04 + 0.12X; R² = 0.60, P = 0.0053; ‘2137’, 2007: Y = 0.41 + 0.02X; R² = 0.36, P = 0.0687; ‘2137’, 2008: Y = 13.6 + 0.17X; R² = 0.57, P = 0.0192; ‘2137’, 2009: Y = 2.33 + 0.10X; R² = 0.54, P = 0.0101.