Host-plant resistance in apple

152 Pages·2008·7.87 MB·English

ETH Library
Host-plant resistance in apple
(Malus x domestica Borkh.) to
common herbivore pests
Doctoral Thesis
Author(s):
Stöckli, Sibylle Carmen
Publication date:
2008
Permanent link:
https://doi.org/10.3929/ethz-a-005711196
Rights / license:
In Copyright - Non-Commercial Use Permitted
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DISS. ETH NO. 17849

Host-plant resistance in apple (Malus x domestica Borkh.) to common
herbivore pests

A dissertation submitted to
ETH ZURICH

for the degree of
Doctor of Sciences

presented by
SIBYLLE CARMEN STÖCKLI
Dipl. Natw. ETH

born 02 October 1976
citizen of Luthern (LU), Switzerland

accepted on the recommendation of

Prof. Dr. S. Dorn, examiner
Dr. M. Kellerhals, co-examiner
Dr. K. Mody, co-examiner

2008
Der Apfelgarten

Komm gleich nach dem Sonnenuntergange,
sieh das Abendgrün des Rasengrunds;
ist es nicht, als hätten wir es lange
angesammelt und erspart in uns,

um es jetzt aus Fühlen und Erinnern,
neuer Hoffnung, halbvergessnem Freun,
noch vermischt mit Dunkel aus dem Innern,
in Gedanken vor uns hinzustreun

unter Bäume wie von Dürer, die
das Gewicht von hundert Arbeitstagen
in den überfüllten Früchten tragen,
dienend, voll Geduld, versuchend, wie

das, was alle Masse übersteigt,
noch zu heben ist und hinzugeben,
wenn man willig, durch ein langes Leben
nur das Eine will und wächst und schweigt.

Rainer Maria Rilke
Table of Contents

1. Summary……………………………………………………………………………….001
2. Zusammenfassung……………………………………………………………………..004
3. General introduction…………………………………………………………………..007
3.1. Insect-plant relationships………………………………………………................. 007
3.2. From the fruit of paradise to the commercial apple………………………………. 007
3.3. Most common apple tree pests……………………………………………………. 009
3.4. Host-plant resistance in apples……………………………………………………. 011
3.5. Molecular approaches in host-plant resistance…………………………………….012
3.6. Thesis outline……………………………………………………………………... 014
4. QTL mapping of resistance in apple to Cydia pomonella and
Lyonetia clerkella, and of two selected fruit traits………………………………….. 015
4.1. Introduction……………………………………………………………………….. 016
4.2. Materials and methods…………………………………………………................. 018
Study site and plant material
Phenotypic data
Data analysis
QTL mapping
4.3. Results…………………………………………………………………………….. 021
Phenotypic data
QTL analysis for C. pomonella and L. clerkella resistance in apple
QTL analysis for fruit number and -diameter
4.4. Discussion………………………………………………………………………… 027
4.5 Supplementary material (SM)……………………………………………………...031
5. Influence of canopy aspect and height on codling moth
(Lepidoptera: Tortricidae) larval infestation in apple,
and relationship between infestation and fruit size………………………………... 032
5.1. Introduction……………………………………………………………………….. 033
5.2. Materials and methods……………………………………………………………. 035
Plant material and orchard locations
Codling moth survey
Measurement of fruit traits
Temperature and wind data
Statistical analysis
5.3. Results…………………………………………………………………………….. 037
Codling moth larval infestation
Canopy aspect
Canopy height
Fruit diameter in uninfested apples
Temperature and wind data
5.4. Discussion………………………………………………………………………… 045
6. QTL analysis for aphid resistance and growth traits in apple…………………….. 048
6.1. Introduction……………………………………………………………………….. 049
6.2. Materials and methods…………………………………………………................. 050
Orchard location and plant material
Aphid survey
Plant-growth characteristics
QTL mapping
Pedigree analysis
Spatial distribution of aphids
Statistical analysis
6.3. Results…………………………………………………………………………….. 055
Aphid infestation
Influence of genotype, site and year on aphid abundance
QTLs for aphid resistance
QTLs for different plant-growth characteristics
Spatial distribution of three aphid species
Relationship between different aphid species
Relationship between different plant-growth characteristics and
aphid infestation
6.4. Discussion……………………………………………………………………….... 069
Genetic background of aphid resistance in apple
Environmental factors related to aphid resistance
Outlook
6.5. Supplementary material (SM)….…………………………………......................... 074
7. Aphis pomi population development, shoot characteristics,
and antibiosis resistance in different apple genotypes……………………………... 079
7.1. Introduction……………………………………………………………………….. 080
7.2. Materials and methods……………………………………………………………. 082
Study site and plant material
Aphid population development in sleeve cages
Shoot characteristics and general tree vigor
Antibiosis-based resistance
Statistical analysis
7.3. Results…………………………………………………………………………….. 084
Aphid population development
Shoot characteristics and general tree vigor
Climatic conditions
Aphid development and shoot characteristics at different sleeve cage positions
Relationship between aphid population development and shoot characteristics
Relationship between aphid population development and general tree vigor
Antibiosis-based aphid resistance
7.4. Discussion………………………………………………………………………… 091
8. Rust mite resistance in apple assessed by quantitative trait loci analysis………….094
8.1. Introduction……………………………………………………………………….. 095
8.2. Materials and methods…………………………………………………................. 097
Orchard characteristics and plant material
Assessment of mites and other herbivores
QTL analysis
Data analysis
8.3. Results…………………………………………………………………………….. 100
Evaluation of rust mite abundance
QTLs for rust mite resistance
Spatial distribution of rust mites
Relationship between rust mite abundance and co-occurring herbivore species
8.4. Discussion………………………………………………………………………… 109
8.5. Supplementary material (SM).……………………………………......................... 112
9. General discussion……………………………………………………………………. 115
9.1. Host-plant resistance……………………………………………………………… 116
9.2. Genetically based resistance in apple to herbivore pests………………................. 117
9.3. Environmental factors influencing the expression of resistance……….................. 119
9.4. Perspectives in apple breeding……………………………………………………. 120
9.5. Conclusion………………………………………………………………………... 121
Appendix: Herbivore resistant and susceptible apple selections:
genetic background and fruit quality…………..…………………………………….... 122
A.1. Objectives………………………………………………………………….......... 123
A.2. Materials and methods…………………………………………………………..123
Plant material and study sites
Herbivore survey and categorization
Fruit quality
Statistical analysis
A.3. Results…………………………………………………………………………… 125
Herbivore resistant apple selections
Genetic background of herbivore resistant and susceptible apple selections
Fruit quality of herbivore resistant and susceptible apple selections
A.4. Conclusion…………………………………………………………………......... 129
10. References……………………………………………………………………………. 131
11. Acknowledgements………………………………………………………………….. 143
12. Curriculum vitae…………………………………………………………………….. 145

Chapters based on:

1 Stoeckli, S., K. Mody, C. Gessler, D. Christen, and S. Dorn. 2009. QTL mapping of
resistance in apple to Cydia pomonella and Lyonetia clerkella, and of two selected fruit
traits. Annals of Applied Biology: in print.
2 Stoeckli, S., K. Mody, and S. Dorn. 2008. Influence of canopy aspect and height on codling
moth (Lepidoptera: Tortricidae) larval infestation in apple, and relationship between
infestation and fruit size. Journal of Economic Entomology 101:81-89.
3 Stoeckli, S., K. Mody, C. Gessler, A. Patocchi, M. Jermini, and S. Dorn. 2008. QTL analysis
for aphid resistance and growth traits in apple. Tree Genetics & Genomes 4:833-847.
4 Stoeckli, S., K. Mody, and S. Dorn. 2008. Aphis pomi population development, shoot
characteristics, and antibiosis resistance in different apple genotypes. Journal of Economic
Entomology 101:1341-1348.
5 Stoeckli, S., K. Mody, A. Patocchi, M. Kellerhals, and S. Dorn. 2008. Rust mite resistance
in apple assessed by quantitative trait loci analysis. Tree Genetics & Genomes doi:
10.1007/s11295-008-0186-5.
1. Summary

In agriculture, arthropod herbivores cause high economic losses by plant feeding and
transmitting plant pathogens. Host-plant resistance is a persistent and environment-friendly
control method, compatible with other integrated pest management methods. The main
objective of the present thesis was to evaluate the genetic basis of resistance in apple (Malus x
domestica Borkh.) to common herbivore pests through quantitative trait loci (QTLs) analyses.
A linkage map of the apple cultivars 'Fiesta' and 'Discovery', saturated with 235 random
amplified polymorphic DNA (RAPD), 475 amplified fragment length polymorphism (AFLP)
and 129 simple sequence repeats (SSR or microsatellite) markers, was the basis for
identifying molecular markers associated with herbivore resistance. A total of 160 highly
heterozygous F progeny plants (genotypes) were investigated for their resistance to two
1
lepidopteran species, the codling moth (Cydia pomonella) and the apple leaf miner (Lyonetia
clerkella); three aphid species, the rosy apple aphid (Dysaphis plantaginea), the leaf-curling
aphids (Dysaphis cf. devecta species complex), and the green apple aphid (Aphis pomi); and
the rust mite (Aculus schlechtendali). Methods for field evaluations comprised quantification
of herbivores per leaf or tree, or a survey of leaves and fruits with damage indicating
infestation by a distinct herbivore species. The field survey was carried out at three orchards
in different regions of Switzerland and during two consecutive years.
The proportion of variation in herbivore infestation that can be explained by the
genetic variation among the apple progenies was analyzed by broad sense heritability (H2). H2
was intermediate and ranged between 15.7% (A. pomi) and 50.2% (D. cf. devecta). The
presence of a genetically based resistance was indicated by genotype being a significant factor
explaining infestation of C. pomonella, D. plantaginea, D. cf. devecta, and A. schlechtendali
(mixed model ANOVA), and confirmed by aggregated occurrence of these herbivores on
individual apple trees (index of dispersion, I values). The comparison of the phenotypic field
D
data and the genotypic markers resulted in a set of QTLs. Except for L. clerkella and A. pomi,
one or more QTLs could be identified for resistance or susceptibility to each herbivore species
investigated. The RAPD marker Z19-350 located at 66.2 cM on the 'Discovery' linkage group
(LG) 10 was associated with higher C. pomonella infestation. The SSR CH04g09y (allele '177
bp'), nearest to this QTL and in coupling with the RAPD marker should be considered to
study resistance to C. pomonella. The QTL explained only 8.2% of the phenotypic variability.
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A QTL associated to D. plantaginea resistance was identified on the 'Fiesta' LG 17. The
AFLP marker E33M35-0269 at 57.7 cM was in close proximity to this QTL, which explained
8.5% of the phenotypic variability. The SSR marker Hi07h02 (allele '255 bp'), which is
coupled with the AFLP marker, was traced back in the pedigree of 'Fiesta' to the apple
cultivar 'Wagener'. A gene region associated to D. cf. devecta resistance on the 'Fiesta' LG 7
was confirmed. The AFLP marker E32M39-0195 (4.5 cM) explained between 10.3% and
20.4% of the phenotypic variability in infestation. The SSR Hi03a10 (allele '216 bp'), which
is coupled with the AFLP marker, was derived from the cultivar 'Blenheim Orange' in the
pedigree of 'Fiesta'. A QTL for A. schlechtendali resistance was identified on 'Fiesta' LG 7.
The AFLP marker E35M42-0146 (20.2 cM) and the RAPD marker AE10-400 (45.8 cM)
explained between 11.0% and 16.6% of the phenotypic variability. An interaction between the
two markers was not found. The SSR Hi03a10 (allele '240 bp') linked to the QTL was traced
back in the 'Fiesta' pedigree to the cultivar 'Wagener'. Host-plant resistance to A. pomi was
studied in more detail by evaluating antibiosis-based resistance. Population development in
sleeve cages was quantified and the results indicated a putative QTL on LG 11 of 'Fiesta'. The
SSR CH02d12 (allele '199 bp') at 21.5 cM explained 14.1% of the phenotypic variability.
As fruit availability and fruit characteristics are of crucial relevance for fruit-feeding
insects, the genetic basis of fruit number and -diameter was evaluated. A putative QTL
associated with fruit number was identified on 'Fiesta' LG 12, with the SSR CH01g12 (43.6
cM) in close proximity. The QTL explained 9.6% of the phenotypic variability and apple
genotypes amplifying the allele '156 bp' produced significantly less apples compared to other
apple genotypes. A significant QTL for fruit diameter was not detected. Besides fruit traits,
also plant-growth traits may influence the expression of herbivore resistance. Knowledge
about the genetic basis of plant-growth traits may elucidate the relationship to herbivore
abundance. Four markers were identified by QTL analysis, and were significantly linked to
stem diameter or shoot length. Increased shoot length was linked to the SSR CH04e05 (allele
'199 bp') at 26.7 cM on the 'Fiesta' LG 7. Increased stem diameter was associated with
markers on the 'Discovery' LG 1, 13, and 14.
Differences in climatic conditions, fruit and plant-growth traits, co-occurring
herbivore fauna, spatial pattern, and infestation level of neighbor trees (neighborhood effect)
effect may have hindered the expression of QTLs for resistance to L. clerkella and A. pomi,
and may have influenced the stability of the QTL associated to C. pomonella infestation. This
is especially supposed for A. pomi and C. pomonella. There was a significant positive
relationship between A. pomi population development and shoot characteristics (measured as
2
shoot length and shoot growth) in spring and early summer, but not in late summer. This
result may be related to a decrease in shoot growth and nitrogen levels, which are highest in
spring and decrease over the growing season. Microclimate conditions may cause within-tree
variability of fruit diameter and of C. pomonella female oviposition preference and blur
differences between genotypes. A significantly lower fruit infestation was observed on the
cooler north- compared with the warmer south- or east-facing tree side. These findings are
important for future monitoring systems focusing on female moths. The complex host-finding
process of arthropod herbivores possibly impeded the evolution of major resistance genes.
Such major resistance genes have been identified for many pathogens, where a host-finding
process is inexistent.
The presented high-resistance-selections have potential to be introduced into apple
breeding combining pest resistance with promising fruit quality. Five selections (13, 22, 189,
265, and 303) have a high potential for breeding apple cultivars with multiple resistance to C.
pomonella, D. plantaginea, D. cf. devecta, A. pomi, and A. schlechtendali.
To conclude, the present thesis provides molecular markers associated with resistance
in apple against herbivores, which can be used in marker-assisted selection or transferred into
new varieties by genetic engineering. The intermediate heritability indicates a partial
resistance, which is of high value in host-plant resistance. The high selection pressure on a
pest of highly resistant plants may lead to adapted biotypes. This risk is minimized in
quantitative traits. Molecular markers are a prerequisite to understand the segregation of
resistance genes among varieties. Furthermore, the resistance in phenotypically evaluated
apple cultivars could be confirmed by testing them for the identified molecular markers.
3