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1. Replant Disease-Resistant Rootstocks
Terence Robinson, Gennaro Fazio, Herb Aldwinckle
Dept. of Horticulture, Cornell University Geneva, New York, 14456
USDA-ARS, Plant Genetics Resources Unit, Geneva, NY 14456

2. Keys to Successful New Apple Orchards
• Plant high-tree densities (optimum ~3,000
trees/ha).
• Produce high early yields (150 t/ha over
the first 5 years).
• Grow the trees rapidly to fill the allotted
space in the first 3 years.
• Produce high mature yields (>60 t/ha) of
high quality fruit.
• Poor tree growth due to replant disease in
the first 3 years jeopardizes the economic
success of the new orchard.

3. Strategies to Overcome Apple Replant Disease
Relative Fumigation Effect on Trunk Cross Sectional Area Growth (2004-2007)
• Soil fumigation
-Expensive 50.00%
40.00%
-Environmental concerns
Percent Growth Increment
30.00%
-Short duration of effect 20.00% 2004
2005
• Soil amendments 10.00% 2006
2007
0.00%
-Limited effectiveness -10.00%
-Expensive -20.00%
WAPATO CHELAN
• Replacing soil Location
-Expensive
-Labor intensive
• Genetic tolerance or resistance of
rootstock
-Effective for life of orchard
-Inexpensive

4. The Geneva Apple Rootstock Breeding and Development Program
Cornell University Program 1968-2008
Dr. James Cummins and Herb Aldwinckle
Joint Program with USDA and Cornell University (1998-present)
Dr. Gennaro Fazio, Herb Aldwinckle and Terence Robinson
Goal: Produce a series of dwarfing rootstocks which are resistant to
important rootstock diseases and insects.
• Resistance to fire blight
• Resistance to Phytopthora root rot
• Resistance to woolly apple aphid
• Cold tolerant
• Resistance to apple replant disease.

5. Tolerance of Geneva® Stocks to Replant Disease
(Empire Experiment, NY 1991)
Relative Tree Relative Growth
Vigor (Virgin Site) at Replant Site Replant
Rootstock (% of M.7) (% of Virgin site) Tolerance
M.7 100 +1 Tolerant
M.26 72 -30 Highly Susceptible
G.210 66 +8 Tolerant
G.30 60 +5 Tolerant
G.935 51 -3 Mod Tolerant
G.202 43 +21 Tolerant
M.9 39 -8 Mod. Susceptible
G.41 36 -4 Mod. Tolerant
B.9 26 +3 Tolerant

6. Growth of Un-grafted Stocks in a Pasteurized and a Replant Soil
0.8
0.7
0.6
Relative Biomass I ndex
0.5
0.4
0.3
0.2
0.1
0
G.11 G.4013 G.7707 G.65 G.8189 G.30 G.210
-0.1
Data redrawn from Isutsa and Merwin 2000

7. Rootstock Liner Growth in Pots
St. Laurent et al., 2010

8. Geneva Replant Disease Evaluation of 38 Genotypes
Kviklys et al

9. % I ncrease in Growth due to Pasteurization
100
120
140
160
180
200
220
240
260
280
300
80
CG
CG.4814
CG.6025
CG.5257
.97
7
G. 3 8
0
CG G.11
.68
G.279
CG 02
CG .4011
CG.2406
.65
8
CG G. 4 9
.41 1
CG 72
.60
2
CG G. 6 4
.68 5
G.274
G.814
CG 90
.85
G.934
6
B.19
B.1 0
1
G. 1 8
G 6
CG .935
CG.6143
CG.6001
CG.5179
M. .5
26E 012
CG MLA
.30
B.407
CG 90
CG.6040
.77
07
M. B.9
9
Rootstock Tolerance to Replant Disease in Potted Trees
Kviklys et al
CG T337
.40
02

10. Field Performance of G.4210 and G.202 in New Zealand
60
% I ncrease due to Virgin Soil
TCA
50
Yield
40
30
20
10
0
G.4210 M .26 G.202 M M .106
-10
-20
(White et al., 2002)

11. % I ncrease in TCA due to Fumigation
10
20
30
0
G
.1
6
G
.4
1
G
.4
21
0
B.
9
G
.3
M 0
.9
T3
37
G
.2
10
G
.9
35
G
M .11
.9
Pa
ja
m
2
M
.7
M
.2
6
Field Tolerance to Replant Disease at 8 Locations in North America
Robinson et al.

12. Gala Production Response to Fumigation in North America
120
TCA Cum. Yield
% I ncrease due to Fumigation Efficiency
100
80
60
40
20
0
6
1
0
9
0
10
35
.11
2
6
37
.7
m
.1
.4
21
.3
.2
B.
M
.2
.9
T3
G
G
G
G
ja
M
.4
G
G
Pa
.9
G
M
.9
M

13. What is the definition of a Resistant Rootstock?
• Traditionally resistance has been defined as similar growth in pasteurized soil and
replant soil.
• However, field trials show that even resistant rootstocks respond to fumigation
with improved yield compared to un-fumigated controls.
• Even if a rootstock can grow well in replant disease soil there appears to be a cost
in yield likely due to the need to invest more carbohydrate resources into root
growth and less into fruit growth

14. Growth of Gala in a Replant Soil
Washington State
Data from Auvil et al. 2010

15. % I ncrease in Growth due to
Fumigation
10
20
30
40
50
60
70
80
0
G.
93
5
G.
41
G.
16
B.
9
G.
21
M 4
.9P
aj
2
Washington State
M
.26
Su
pp
2
G.
11
Su
Growth of Gala in a Replant Soil
pp
3
Su
pp
M
.9N 1
ic2
9
Data from Auvil et al. 2010

16. Yield of Gala in a Replant Soil
Washington State
Data from Auvil et al. 2010

17. Early Yield Improvement of Gala due to Fumigation in a Replant Soil
Washington State
WAPATO 2006-2007 Cumulative Yield Per Tree (Kg)
% I ncrease in Yield due to
60
50
Fumigation
40
30
20
10
0
35
14
1
j2
9
6
p1
29
6
.11
p3
p2
.4
.1
.2
d.
Pa
.9
.2
Su
ic
Su
Su
G
Bu
M
G
G
N
G
G
.9
.9
M
M
Rootstock
Data from Fazio

18. Growth of Gala in a Replant Soil
Washington State
Data from Auvil et al. 2010

19. % I ncrease in Growth due to
Fumigation
-10
10
20
30
40
50
0
G.
93
5
G.
41
M
.9P
aj
2
G.
16
Su
pp
1
Washington State
G.
11
B.
M 9
.9N
ic2
M 9
.9T
33
Growth of Gala in a Replant Soil
7
Su
pp
2
M
.26
Data from Auvil et al. 2010

20. Yield of Gala in a Replant Soil
Washington State
Mean Cumulative Yield Per Tree (2006-2007) CHELAN
8
7
6
5
Kg 4
FUMIG
3 NoFUM
2
1
0
M 26
G 11
G 16
B d9
S p1
S p2
S p3
2
83
N ic 29
G 935
G 041
7
N ak 33
P jam
P a u 56
-
-
-
u
u
u
u
b
3
5
a
i
Data from Fazio

21. Yield of Gala in a Replant Soil
Washington State
Mean Cumulative Yield of Highest and Lowest Three Rootstocks
9.6%
8
7
G.935
6
G.935 G.41 60%
G.41 66% G.16
5
G.16 Highest Three
Kg 4 Lowest Three
3
B.9
2 B.9 Supp.2
M.26 Supp.1
1
Nic.29
0
NoFUM FUMIG
Data from Fazio

22. Yield of Gala in a Replant Soil
Washington State
Data From Auvil et al. 2012

23. % I ncrease in Yield due to
Fumigation
-10
100
10
20
30
40
50
60
70
80
90
0
CG
.
CG 2034
.62
10
CG G.16
.3
CG 007
.40
CG 13
.
CG 935
CG .214
.48
1
Washington State
G. 4
22
2
G.
CG 30
.
CG 5046
M .51
.9E 79
M
CG L A
.50
12
Yield Increase of Gala in a Replant Soil
G.
41
B.
9
Data From Auvil et al. 2012

24. Growth of Fuji in a Replant Soil
Washington State
Data From Auvil et al. 2010

25. Growth of Fuji in a Replant Soil
Washington State
Data From Auvil et al. 2010

26. Summary of Replant Resistance Studies
Study G.11 G.41 G.214 G.935 G.210 G.30 M.9 M.26
Robinson 1991 -- T -- T R R S S
Isutsas 2000 S -- -- -- R R -- --
Laurent 2010 -- S -- R R S S R
Kviklys 2012 R R R T -- R S S
White 2000 -- -- -- -- -- -- -- R
Robinson 2012 T R -- T T R T S
Auvil 2010(Wapato) T R T R -- -- -- T
Auvil 2010(Chelan) -- R -- R -- -- S S
Average T R R R R R S S

27. G.11
• Tree size similar to M.9 T337.
• Productivity is similar to M.9.
• Large fruit size
• Tolerant to Replant Disease
Geneva® 11 M9-T337
• Resistant to Fire Blight but not
immune.
• Resistant to Crown Rot
• Not tolerant to replant disease
• Susceptible to Wooly Apple Aphid
• Good rooting in stoolbed
Courtesy of Stefano Musacchi

28. G.41
• M.9 vigor
• Highly yield efficient
• Highly productive
• Very precocious
• Resistant to replant disease
• Very cold hardy
• Does well in warmer climates
(Mexico)
• Immune to Fire Blight and Crown Rot
and Wooly Apple Aphid
• Requires tissue culture mother plants
for stoolbed
G.41 Fuji CIV 2008

29. G.214
 Vigor similar to M.9 Pajam2
 Highly yield efficient
 Highly productive
 Good precocity
 Tolerant to replant disease
 Resistant to Fire Blight, Crown
Rot and Wooly Apple Aphid
 Very good stool bed propagation
 No commercial production of
liners.
G.214 Washington

30. G.935
• Vigor intermediate between M.9
Pajam 2 and M.26
• Very cold hardy
• Resistant to Replant Disease
• Resistant to Fire Blight and Crown
Rot
• Tolerant to Replant Disease
Complex
• Susceptible to Wooly Apple Aphid
• Production in US ~50,000 plants in
2011.

31. G.202
• It is similar in size to M.26
• Precocious, productive
• It is resistant to woolly apple
aphid, fire blight, and crown rot
• In New Zealand it has been a top
performer
• Good choice for weak growing
cultivars like Honeycrisp
• Tolerant to apple replant disease
• Moderate rooting in stoolbed G.202 New Zealand

32. G.210
• Vigor between M.7 and MM.106
• Precocious, productive G.210
• Yield efficiency similar or better
than M.9
• Resistant to apple replant disease.
• Resistance to woolly apple aphid,
fire blight, and crown rot.
• Good rooting in stoolbed few
spines.
• Mostly for Organic Production

33. Released Geneva® Apple Rootstocks Arranged by Tree Size
Seedling Size
M.7-MM106 Size
M.26 Size
M.9 PAJ 2
M.9 T337
M.27 Size
G.65 G.11 G.41 G.935 G.202 G.30
G.16 G.214 New
G.969 G.210 G.890 Releases
G.222 G.213

34. Summary
• Several Geneva® rootstocks appear to have tolerance/resistance to
apple replant disease.
– G.41
– G.214
– G.935
– G.202
– G.210
• The resistance may be due to the initial screening for Phytopthora
disease which may also have selected for tolerance to other soil
microorganisms.
• Resistant rootstocks show an improvement in yield due to
fumigation.
• The variation around the world in soil organisms which cause apple
replant disease may result in variable orchard results with the
resistant rootstocks.

35. Questions?