Evaluation of Claviceps purpurea isolates on wheat reveals complex virulence and host susceptibility relationships

Figures & data

Table 1. Single spore isolates of Claviceps purpurea (Fr.) Tul. assessed for pathogenic variation on lines of hexaploid wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. var. durum).

Isolate	Year of isolation	Location of collection	Host source
7-1^a (250621^b)	1996	MB07^c	Triticale (× Triticosecale)
7-2 (250622)	1996	MB07	Triticale
7-3 (250623)	1996	MB07	Triticale
22 (250627)	1996	MB07	Barley
24 (250628)	1996	AB05	Barley
29-2 (250632)	1996	SK09	Barley
33-2 (250636)	2000	AB05	Barley
38	1997	MB07	Barley
40 (250638)	1997	SK08	Barley
44-2 (250641)	1997	MB09	Barley
77 (250646)	2000	SK03	Wheat
85 (250648)	2000	AB04	Wheat
89-1 (250649)	2000	SK01	Rye
90 (250650)	2000	SK08	Rye
93-2	2000	MB01	Rye
95 (250652)	2000	MB01	Rye
97	2000	AB07	Wheat
98 (250653)	2000	MB01	Durum Wheat
100	2000	MB01	Wheat
101	2000	MB01	Rye
102	2000	MB03	Wheat
115 (250657)	2000	MB07	Winter Wheat
125 (250658)	2000	SK01	Durum Wheat
128 (250659)	2000	SK02	Durum Wheat
138	2000	SK05	Wheat
148	2000	SK07	Rye (Secale cereale L.)
150 (250661)	2000	SK08	Durum Wheat
155	2000	SK08	Durum Wheat
166-1	2000	AB01	Durum Wheat
169-1 (250664)	2000	AB02	Durum Wheat
169-6 (250668)	2000	AB02	Durum Wheat
172	2000	AB02	Wheat
179-1 (250670)	2000	AB04	Rye
179-2 (250671)	2000	AB04	Rye
179-3 (250675)	2000	AB04	Rye
192-1 (250678)	2005	MB07	Oats
192-4 (250679)	2005	MB07	Oats
UK 03-20-1	2003	Cambridge U.K.	Wheat
UK 03-43-1 (250717)	2003	Cambridge, U.K.	Winter Wheat
UK 04-02-1	2004	Cambridge, U.K.	Blackgrass (Alopecurus myosuroides Huds.)
UK 04-97-1	2004	Cambridge, U.K.	Blackgrass

^aMore than one sclerotium could be obtained from one site. The first number represents the collection number and the number following the hyphen represents the number of the sclerotium sampled from that site in the instance of hyphenated isolate designations.

^bNumbers in parentheses are the DAOMC number for those isolates deposited at the Canadian National Mycological Herbarium, Ottawa, ON, Canada.

^cUnless otherwise indicated, the isolates originated in western Canada. Location of collection for Canadian isolates indicates the provincial crop districts in Manitoba (MB), Saskatchewan (SK) and Alberta (AB).

Table 2. The least squares means for the honeydew ratings^a obtained from the inoculation of 41 single spore strains of Claviceps purpurea (Fr.) Tul. onto three lines of durum wheat (T. turgidum L. var. durum) and five lines of hexaploid wheat (Triticum aestivum L.).

	Durum Wheat Line			Hexaploid Wheat Line
Fungal Strain	9260B-173A	‘Kyle’	‘Melita’	HY630	‘Kenya Farmer’	‘Lee’	‘Vista’	‘Cadillac’
7-1	1	3.2	3.7	1.9	1.4	2.7	2.7	2.9
7-2	1	2.7	3.9	1.6	1.2	3.4	2.9	2.4
7-3	2.2	1.9	3.7	2	1.7	2.9	1.9	2.9
22	1	1.4	2.7	1	1	1.4	1.4	1.7
24	1.7	2.2	2.9	1.3	2.4	1.2	1.7	2.9
29-2	1.4	2.4	3.4	1	1.2	2.4	1.7	1.9
33-2	1	1.4	3.4	1.9	1.4	2.7	1.4	2.7
38	1	1	3.2	1	1	1.4	1.9	1
40	1	2.7	2.7	1.9	1	1.4	2.7	1.9
44-2	1	2.2	3.4	3	2.2	2.9	3.4	2.9
77	1	2.5	3.9	1	1	1.5	2.6	2.1
85	1.9	1.9	3.9	2.3	1.7	2.9	2.7	2.9
89-1	1.7	2.7	3.9	3.4	3.2	3.7	3.7	3.9
90	1	2.9	3.4	3.4	2.9	2.9	3.4	3.7
93-2	1	2.9	3.4	3.7	3.4	3.7	3.7	3.9
95	1	2.9	3.7	3.7	2.9	3.7	3.9	3.7
97	1	1.2	1.7	2.5	1	1.2	1.4	1
98	2.4	1.9	2.7	1.5	1	1.7	1.9	2.2
100	1	2.7	2.9	1.5	1	1.2	2.2	1.2
101	1	3.4	3.7	3.4	3.2	3.9	3.9	3.9
102	1	2.2	3.2	2.3	1	2.7	2.7	2.9
115	1	1.2	2.7	1.5	1	1.7	2.7	2.7
125	1	2.4	3.9	2	1.9	3.2	2.9	2.9
128	1	2.4	3.2	1	1.9	2.4	2.7	2.9
138	2.9	1.4	2.2	2.9	1	2.2	2.4	1.9
148	1	3.4	3.4	3.4	3.2	3.4	2.7	3.7
150	1	1.9	3.7	1	1.2	1.4	1	2.7
155	1.2	3.4	3.9	3	2.7	2.7	3.9	3.9
166-1	1	3.4	3.9	1.9	1.7	3.2	3.2	2.9
169-1	3.2	3.2	3.9	3.9	3.2	3.4	3.9	3.9
169-6	1	3.4	3.4	3.7	3.2	3.2	3.4	3.2
172	1	2.4	2.9	2	1	1	1.2	1.2
179-1	1	2.2	3.4	3	2.2	2.9	3.4	2.9
179-2	1	3.9	3.9	3.9	3.4	3.7	3.9	3.9
179-3	2.4	3.5	3.9	2.7	1	1.9	2.2	1.9
192-1	1.9	2.9	3.4	1.9	1	1.2	1.7	1
192-4	1	1.2	3.2	2.9	1.4	2.4	2.9	1.9
UK 03-20-1	2	2.9	3.9	3.4	2.7	2.9	3.7	3.4
UK 03-43-1	3.6	2.6	3.9	2.8	2.9	3	3.6	3
UK 04-02-1	3.5	3	3.8	3.2	2.8	3.4	4	3.6
UK 04-97-1	3.2	2.4	3.7	2.2	2.4	3.2	2.7	3.7

^aHoneydew Rating Scale was 1 = none visible, 2 = honeydew confined within the glumes, 3 = honeydew exuding from the florets in small drops, 4 = large drops of honeydew running down the spikes (Menzies 2004). An isolate of C. purpurea was considered virulent on a wheat line if it caused a honeydew production rating of 2.1 or greater.

Table 3. The least squares means of the weight (mg) of sclerotia per spike obtained from the inoculation of 41 single spore strains of Claviceps purpurea (Fr.) Tul. onto three lines of durum wheat (T. turgidum L. var. durum) and five lines of hexaploid wheat (Triticum aestivum L.).

	Durum Wheat Line			Hexaploid Wheat Line
Fungal Strain	9260B-173A	‘Kyle’	‘Melita’	HY630	‘Kenya Farmer’	‘Lee’	‘Vista’	‘Cadillac’
7-1	3^a	80	78	8	30	93	244	188
7-2	3	10	139	21	34	132	271	97
7-3	48	14	288	104	31	152	192	260
22	0	2	41	13	0	23	95	102
24	22	16	66	9	209	55	155	132
29-2	3	35	155	12	36	186	144	128
33-2	6	6	93	15	46	281	130	99
38	0	4	33	6	4	23	184	19
40	2	10	169	54	33	74	190	75
44-2	71	43	319	93	169	291	536	306
77	2	44	169	2	8	17	125	47
85	10	18	84	60	44	424	489	357
89-1	5	27	185	297	604	368	514	714
90	9	124	337	412	691	538	734	1179
93-2	2	102	260	472	747	444	682	1150
95	18	39	641	218	253	257	579	870
97	17	4	54	94	19	40	82	50
98	20	17	57	92	134	295	246	75
100	18	41	158	28	6	21	191	83
101	40	98	630	323	278	505	543	619
102	0	7	61	29	7	127	57	183
115	0	10	47	19	43	145	149	250
125	23	174	674	25	81	217	380	497
128	3	6	96	24	46	225	231	259
138	80	6	141	146	16	324	109	190
148	2	169	550	371	681	543	335	978
150	0	17	101	0	14	52	75	101
155	2	48	304	184	156	345	397	557
166-1	9	424	777	9	224	371	400	524
169-1	92	77	997	440	399	426	842	911
169-6	16	33	272	290	617	168	580	454
172	4	40	90	113	28	50	130	62
179-1	17	125	638	481	449	420	765	1201
179-2	13	400	925	257	469	535	704	853
179-3	99	206	514	126	4	49	55	204
192-1	59	133	195	24	2	41	83	31
192-4	27	25	287	139	25	82	164	49
UK 03-20-1	59	103	320	118	49	91	420	13
UK 03-43-1	212	31	356	238	272	188	282	250
UK 04-02-1	195	142	278	115	133	130	457	531
UK 04-97-1	129	31	377	107	57	143	64	316

^aAn isolate of C. purpurea was considered virulent on a wheat line if it caused a sclerotial weight per spike of 81 mg or greater.

Fig. 1 (Colour online) Correspondence analysis biplot of the contingency table involving wheat differential line, isolate sampling location and isolate host source for honeydew production (H1 to H4). The graph is derived from the eigenanalysis of these contingency tables. The first eigenvector accounted for 73.2% of the variation in the contingency tables, and the second eigenvector accounted for 23.2% of the variation. The path from H1 to H4 indicates increasing honeydew production with means of 1.0, 2.0, 3.0 and 4.0 for H1, H2, H3 and H4, respectively. Wheat differential lines: 9260B-173A (9260B), ‘Kyle’, ‘Melita’, HY630, ‘Kenya Farmer’, ‘Lee’, ‘Vista’, ‘Cadillac’. Isolate sampling location: United Kingdom (UK), Alberta (AB), Saskatchewan (SK), Manitoba (MB). Isolate host source: rye (Rye), blackgrass (BG), triticale (Tri), durum wheat (Dur), hexaploid wheat (Wht), oats (Oat), barley (Bar).

Fig. 2 (Colour online) Correspondence analysis biplot of the contingency table involving wheat differential line, isolate sampling location and isolate host source for sclerotial weight per spike (Sc1 to Sc4). The graph is derived from the eigenanalysis of these contingency tables. The first eigenvector accounted for 80.9% of the variation in the contingency tables, and the second eigenvector accounted for 16.3% of the variation. The path from Sc1 to Sc4 indicates increasing sclerotial weight with means of 11.2, 80.1, 226.9 and 610.5 for Sc1, Sc2, Sc3 and Sc4, respectively. Wheat differential lines: 9260B-173A (9260B), ‘Kyle’, ‘Melita’, HY630, ‘Kenya Farmer’, ‘Lee’, ‘Vista’, ‘Cadillac’. Isolate sampling location: United Kingdom (UK), Alberta (AB), Saskatchewan (SK), Manitoba (MB). Isolate host source: rye (Rye), blackgrass (BG), triticale (Tri), durum wheat (Dur), hexaploid wheat (Wht), oats (Oat), barley (Bar).

Menzies JG. 2004. The reactions of Canadian spring wheat genotypes to inoculation with Claviceps purpurea, the causal agent of ergot. Can J Plant Sci. 84:625–629.

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