Fruit tree canker in apple, caused by the fungus Nectria galligena, is

Fruit tree canker in apple, caused by the fungus Nectria galligena, is

Screening for Partial Resistance to
Fruit Tree Canker in Apple Cultivars
1*
1
1
1
2
M. Ghasemkhani , J. Sehic , M. Ahmadi-Afzadi , H. Nybom and L. Garkava-Gustavsson
1
Swedish University of Agricultural Sciences, Department of Plant Breeding and Biotechnology, Balsgård, Fjälkestadsvägen 459, 29194 Kristianstad, Sweden
2
Swedish University of Agricultural Sciences, Department of Plant Breeding and Biotechnology, Box 101, 230 53 Alnarp, Sweden
*
Corresponding Author: [email protected], [email protected]
Introduction
Fruit tree canker in apple, caused by the fungus Nectria galligena,
is considered as a serious economic problem in apple orchards
especially in northwestern Europe. Not even chemical control with
fungicides is sufficient for protecting the trees. Apple cultivars
show variable levels of partial resistance to the fungus whereas
complete resistance is not known. Therefore the aim of this study
was to identify partially resistant cultivars that can be used in plant
breeding as sources of resistance to N. galligena.
90
Åkerö
80
Elise
70
Gloster
60
Gyllenkrok's Astrakan
50
Jonathan
40
Röd Gravenstainer
30
Rödluvan
20
Rubinola
10
Sävstaholm
William's pride
0
Time 1
Time 2
Time 3
120
Time 4
Time 5
Åkerö
Elise
100
Gloster
80
Gravensteiner, Red
Gyllenkrok's Astrakan
60
Jonathan
40
Rödluvan
Rubinola
20
Sävstaholm
0
Time 1
Time 2
Time 3
Time 4
Time 5
Time 6
William's Pride
Fig. 3. Canker development on cut shoots
100
Fig. 4.Canker development on potted trees
‘Rödluvan’ was the most resistant cultivar in both
experiments, while ‘Jonathan’ was the most susceptible
cultivar in the cut-shoots experiment (Fig. 3) and
‘Åkerö’ in the potted-trees test (Fig. 4). The other
cultivars showed varying levels of resistance when the
two different methods were compared. Results may be
used for furthur studies to select resistant cultivars for
breeding programs.
Infection average (mm)
Results
Ten cultivars were used in two experiments.
Expriment 1. Cut shoots were inoculated and then kept
under a plastic tent in a greenhouse while symptoms
developed (Fig. 1).
Expriment 2. One-year-old potted trees were inoculated in a
greenhouse (Fig. 2).
In both experiments, lesion length was measured and sum of
the values for each assessments were calculated. Area under
the curve (AUC) was then calculated and used for ANOVA.
Infection average (mm)
Fig. 2. Potted apple trees
Fig. 1. Cut shoots
Material and Methods