Multiple Disease Resistance in Dogwoods (Cornus spp.) to Foliar Pathogens

M.T. Mmbaga; R.J. Sauvé

doi:10.48044/jauf.2004.012

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Table 1.

Cornus cultivars resistant to powdery mildew under field conditions 1998–2001.

Cornus species	Cultivar	Mean powdery mildew severity^z					Mean
Cornus species	Cultivar	1998	1999	2000	2001	2002	Mean
C. kousa	Agate	0 i^y	0 j	0 j	0 l	0.0 h	0
C. kousa	Autumn Rose	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Big Apple	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Blue Shadow	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	China Girl	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	var. chinensis	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Dwarf Pink	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Emerald Star	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Gold Star	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Lustgarten Weeping	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Moonbeam	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Satomi	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Square Dance	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Wolf Eyes	0 i	0 j	0 j	0 l	0.0 h	0
C. sericea	Cardinal	0 i	0 j	0 j	0 l	0.0 h	0
C. sericea	Isante	0 i	0 j	0 j	0 l	0.0 h	0
C. mas	Redstone	0 i	0 j	0 j	0 l	0.0 h	0
C. mas	Golden Glory	0 i	0 j	0 j	0 l	0.0 h	0
C. alternifolia	Pagoda	0 i	0 j	0 j	0 l	0.0 h	0
C. kousa	Trinity Star	0 i	0 i	____	____	0.0 h	0
C. kousa	Japanese Cornel	0 i	0 i	____	____	0.0 h	0
C. kousa	Milky Way	0.7 hi	0.5 hij	0 j	0 l	0.2 h	0.
C. kousa	Snow Flake	0.3 i	0.6 hij	0 j	0 l	0.0 h	0.2
C. kousa × C. florida	Stellar Pink	0.0 i	0.3 i	0.1 j	0.3 kl	0.5 h	0.2
C. kousa × C. florida	Celestial	0.7 hi	0.5 hij	0.1 j	0.3 kl	0.3 h	0.4
C. kousa × C. florida	Constellation	1.0 hi	0.5 hij	0.5 j	0.5 jkl	0.5 h	0.6
C. kousa × C. florida	Aurora	1.0 hi	1.0 fghij	0.5 j	0.8 jkl	____	0.8
C. florida	Fragrant Cloud	1.0 hi	0.4 ij	2.5 ghi	1.5 fgh	3.0 def	1.4
C. kousa × C. florida	Ruth Ellen	1.0 hi	1.0 fghi	2.4 i	2.5 cde	0.5 h	1.7
C. florida	Cherokee Brave	2.3 ef	0.5 hij	2.1 ef	2.9 cd	1.8 g	1.9
	LSD_(0.05)	1.1	1.1	0.9	0.8	1.1

↵^z Disease severity readings 1 = 1% to 10%, 2 = 11% to 25%, 3 = 26% to 50%, 4 = 51% to 75%, and 5 = 76% to 100% plant infection.
↵^y Statistical differences between cultivars are presented across Tables 1–2. Numbers followed by same letters in the same column are statistically similar at P = 0.05 according to t-tests between pairs of means calculated by Statistical Analysis Systems (SAS).

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Table 2.

Cornus cultivars susceptible to powdery mildew under field conditions 1998–2002.

Cornus species	Cultivar	Mean powdery mildew severity^z					Mean
Cornus species	Cultivar	1998	1999	2000	2001	2002	Mean
C. florida	Little Princess	1.0 hi^y	0.4 ij	2.5 ghi	3.3 ab	3.0 def	2.0
C. kousa	Bush Pink	2.0 fgh	0.4 ij	2.9 efgh	2.6 cde	____	2.0
C. florida	World’s Fair	2.0 fgh	0.5 hij	2.6 fgh	2.5 cde	2.7 efg	2.1
C. nutalli	Boyd	____	1.0 fghi	3.0 i	2.1 ef	2.5 fg	2.2
C. kousa	Spring Grove	1.7 fghi	0.5 hij	2.3 hi	2.5 cde	4.3 ab	2.3
C. florida	Pink Beauty	2.0 ef	2.5	2.5 cde	3.0 bc	2.5 efg	2.5
C. florida	Pygmy	1.7 gh	2.4	3.5 bcde	2.6 bcd	2.3 fg	2.5
C. florida	Sterling silver	____	2.3	1.8 i	3.3 ab	2.8 ef	2.6
C. florida	Plena	1.0 hi	2.2	3.0 defgh	3.0 bc	4.0 ab	2.6
C. florida	Red Beauty	3.3 bcd	2.7	3.5 bcde	2.3 cde	2.3 fg	2.8
C. florida	Cherokee	3.0 bcd	2.5	____	____	____	2.8
C. florida	Barton	2.3 def	2.3 bcd	2.4 hi	2.0 ef	5.0 a	2.8
C. florida	Cherokee Chief	3.3 bc	2.7	3.6 bcd	1.4 gh	3.8 abc	3.0
C. florida	Cherokee Princess	3.0 bcd	3.0	3.4 bcde	3.1 bc	2.7 efg	3.0
C. florida	Wonderberry	3.0 bcd	3.1	3.0 defh	____	____	3.0
C. florida	Cloud 9	2.7 def	3.0	3.5 bcde	2.1 efg	4.5 a	3.2
C. florida	Rainbow	3.0 bcd	2.8	3.8 bcd	2.0 efg	4.3 ab	3.2
C. florida	Rubra	3.7 bc	3.3	2.9 abc	2.9 bcd	3.2 cde	3.2
C. florida	Cherokee Sunset	5.0 a	2.5 bcd	3.3 cdef	2.5 cde	4.0 ab	3.5
C. florida	Ozark Spring	2.3 ef	3.2 ab	4.6 a	3.5 ab	3.5 bcd	3.4
C. florida	Purple Glory	4.0 ab	3.6 a	4.0 abc	4.0 a	5.0 a	4.1
	LSD_(0.05)	1.1	1.1	0.9	0.8	1.1

↵^z Disease severity readings 1 = 1% to 10%, 2 = 11% to 25%, 3 = 26% to 50%, 4 = 51% to 75%, and 5 = 76% to 100% plant infection.
↵^y Statistical differences between cultivars are presented across Tables 1–2. Numbers followed by same letters in the same column are statistically similar at P = 0.05 according to least significant differences calculated by Statistical Analysis Systems (SAS).

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Table 3.

Cornus cultivars that showed different levels of susceptibility to spot anthracnose and Septoria leaf spot under field conditions 2001–2002.

Cornus species	Cultivar	Mean disease severity^z
		Spot anthracnose		Septoria leaf spot
		2001	2002	2001	2002
C. sericea	Cardinal	0.0 o^y	0.0 o	4.8 a	5.0 a
C. sericea	Isante	0.0 o	0.0 o	4.9 a	4.6 a
C. kousa	Lustgarten Weeping	1.5 fghij	3.7 b	0.0 o	0.0 o
C. kousa	Satomi	2.8 b	2.5 c	0.0 o	0.0 o
C. mas	Golden Glory	2.8 bc	2.2 cd	0.0 o	0.0 o
C. kousa	Wolf Eyes	2.8 b	2.3 c	0.0 o	0.0 o
C. florida	Cherokee Sunset	2.5 bcd	2.3 c	0.0 o	0.0 o
C. florida	Little Princess	2.3 bcde	1.3 def	0.0 o	0.0 o
C. kousa	Dwarf Pink	1.0 hijklm	3.3 b	0.0 o	0.0 o
C. florida	Cherokee Chief	1.4 fghijk	2.0 cd	0.0 o	0.0 o
C. florida	Rainbow	2.6 bc	1.3 def	0.0 o	0.0 o
C. florida	Pink Beauty	2.0 bcde	1.3 def	0.0 o	0.0 o
C. kousa	Spring Grove	1.8 defgh	2.0 cd	0.0 o	0.0 o
C. mas	Redstone	1.4 fghijk	2.2 cd	0.0 o	0.0 o
C. florida	Cherokee Brave	1.3ghijkl	1.3 def	0.0 o	0.0 o
C. florida	Rubra	1.9 cdefg	0.7 efg	0.0 o	0.0 o
C. florida	Purple Glory	1.8 defgh	1.0 efg	0.0 o	0.0 o
C. kousa	Emerald Star	1.0 hijklm	1.1 def	0.0 o	0.0 o
C. florida	Sterling Silver	1.6 efghi	0.3 gh	0.0 o	0.0 o
C. florida	Red Beauty	1.4 fghijk	0.3 gh	0.0 o	0.0 o
C. kousa	Agate	0.0 o	1.5 cde	0.0 o	0.0 o
C. kousa	China Girl	0.4 mno	1.3 def	0.0 o	0.0 o
LSD_(0.05)		0.8	0.8	0.8	0.8

↵^z Disease severity readings 1 = 1% to 10%, 2 = 11% to 25%, 3 = 26% to 50%, 4 = 51% to 75%, and 5 = 76% to 100% plant infection with spot anthracnose (Elsinoe corni) and Septoria leaf spot (Septoria cornicola).
↵^y Numbers followed by same letters in the same year are statistically similar at P = 0.05 according to t-tests between pairs of means calculated by Statistical Analysis Systems (SAS). Similar data were obtained in 1999–2000; data were not taken in 1998.