UNIVERSITI PUTRA MALAYSIA
EFFECTS OF TRICHODERMA-INDUCED SUPPRESSIVE SOIL ON FUSARIUM WILT OF TOMATO
ROZLIANAH FITRI BTE SAID.
FP 2005 21
EFFECTS OF TRICHODERMA-INDUCED SUPPRESSIVE SOIL ON FUSARIUM WILT OF TOMATO
BY
ROZLIANAH FlTRl BTE SAID
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements for the Degree of Master of
Agricultural Science
May 2005
DEDICATION
SpeciaC&diuatwn to:
My &amst mottiec 6rothers a n d h n for their end&ss ad6ou&s liwe, udmtanding andencour~~ement throughout my study.
Not forgetting, my 6eGwedlhte fattier, t t i a e o u for en&s h u n y o u spent with me. I r e d y missedyou.. .
~bstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment of the requirement for the Degree of Master of Agricultural Science
EFFECTS OF TRICHODERMA-INDUCED SUPPRESSIVE SOIL ON FUSARIUM WILT OF TOMATO
ROZLIANAH FlTRl BTE SAID
May 2005
Chairman : Professor Sariah Meon, PhD
Faculty : Agriculture
Twenty-two isolates of Fusarium spp. were isolated from stems and roots of
tomato plants showing symptoms of foliar wilting and brown discoloration of the
vascular systems. Differentiation of the isolates based on cultural and
morphological characteristics had identified twelve isolates of F. oxysporum, six
isolates of F. solani, two isolates of F. moniliforme, one isolate of F.
chlamydosporum and one isolate of F. lateritium. However, the colonies of
Fusarium oxysporum f. sp. lycopersici (FOL) appearance are not easy to
distinguish from those of the non-pathogenic F. oxysporum even though they
can be differentiated from other species. Species aggregates of Fusarium were
further distinguished based on the DNA polymorphism. Twenty 10-mer primers
were used in the initial screening of the fungal DNA and three (OPC-11, OPC-15
and OPC-18) were selected. Based on UPGMA clustering, two main clusters
were defined. F. oxyspomm were grouped in Cluster I and F. solani were
grouped in Cluster II. The other isolates of F. moniliforme, F. chlamydosporum
and F. lateritium were distinctly isolated from these two main clusters.
Pathogenicity testing was carried out on tomato cultivars Baccarat 322 and
Cherry to further confirmed the differentiation between FOL and other forms of
F. oxysporum. Isolate M I produced symptoms of Fusarium wilt on Baccarat 322
and Cherry, and therefore identified as Fusarium oxysporum f. sp. lycopersici
(FOL). However, percentage of disease incidence was higher on Baccarat 322
variety (65.55%) compared to Cherry (29.44%). Histopathological studies of
infected stems of tomato inoculated by isolate MI further confirmed the
presence of fungal mass in the xylem vessels. Tomato plants with Trichoderma-
induced suppressive soil (UPM 40 and UPM 23) individually and as mixture
(UPM 2340) gave increased in plant height, fresh weight and dry weight of leaf
and root, early flower initiation and increase in yield compared to control.
Disease incidence of Fusarium wilt was significantly lower at week 12 (12%)
when treated with UPM 2340, followed by UPM 40 (21%), UPM 23 (29.5%) and
compost alone (59.5%). Control gave the highest value of disease incidence of
100% at week 12. The experiment carried out in this study indicated that
treatments with UPM 2340, UPM 40 and UPM 23 improved vigor of tomato
plants and was effective in inducing suppressiveness against Fusarium wilt
development, suggesting their potential role as biological control in the
management of Fusarium wilt.
Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan untuk ijazah Master Sains Pertanian
KESAN TANAH PENINDAS ARUHAN TRICHODERMA TERHADAP LAYU FUSARIUM PADA TANAMAN TOMATO
Oleh
ROZLIANAH FlTRl BTE SAID
Mei 2005
Pengerusi : Professor Sariah Meon, PhD
Fakulti : Pertanian
Dua puluh dua isolat Fusarium spp. telah dipencilkan daripada batang dan akar
tanaman tomato yang menunjukkan gejala layu pada daun dan pewarnaan
coklat kemerahan pada sistem vaskularnya. Perbezaan isolat-isolat tersebut
berdasarkan ciri-ciri kultur dan morfologinya telah dapat mengenalpasti dua
belas isolat F. oxysponrm, enam isolat F. solani, dua isolat F. monilifonne, satu
isolat F. chlamydosponrm dan satu isolat F. lateritium. Walau bagaimanapun,
kemunculan koloni Fuserium oxysporum f. sp. lycopersici (FOL) adalah sukar
untuk dibezakan daripada F. oxysponrm lain yang tidak patogenik, walaupun, ia
boleh dibezakan daripada spesies-spesies lain. Spesies agregat Fusarium
seterusnya dibezakan berdasarkan polimorfisme DNA. Dua puluh jenis primer
telah digunakan untuk saringan pada peringkat awal DNA kulat dan tiga
daripadanya (OPC-11, OPC-15 dan OPC-18) telah dipilih. Berdasarkan pada
pengumpulan UPGMA, dua kumpulan utama telah dikenafpasti sebagai F. - - -
oxysporum yang dikumpulkan dalam kumpulan I dan F. solani yang
dikurnpulkan dalam kumpulan II. Isolat-isolat lain seperti F. moniliforme, F.
chlamydosponrm dan F. lateritium adalah dengan jelas terasing daripada dua
kurnpulan utama tersebut. Ujian patogenisiti telah dilakukan pada kultivar
tomato Baccarat 322 dan Cherry untuk pengesahan selanjutnya terhadap
perbezaan di antara FOL dan F. oxysporum yang lain. lsolat M I menghasilkan
gejala layu Fusarium pada Baccarat 322 dan Cherry, dan oleh itu ia telah
dikenalpasti sebagai Fusatium oxysporum f. sp. lycopersici (FOL). Walau
bagaimanapun, peratusan insiden penyakit adalah lebih tinggi pada varieti
Baccarat 322 (65.55%) berbanding Cherry (29.44%). Kajian histologi terhadap
jangkitan pada batang tanaman tomato yang telah diinokulat dengan isolat M I
seterusnya mengesahkan kehadiran kulat di dalam saluran xilem. Tanaman
tomato dengan tanah penindas aruhan Trichodema (UPM 40 dan UPM 23)
secara individu dan campuran (UPM 2340) telah mernberikan peningkatan
terhadap tinggi pokok, berat segar dan berat kering daun dan akar, inisiasi
bunga dan peningkatan hasil berbanding kawalan. lnsiden penyakit layu
Fusarium adalah lebih rendah secara signifikan pada minggu ke-12 (12%)
apabila dirawat dengan UPM 2340, diikuti oleh UPM 40 (21%), UPM 23 (29.5%)
dan kornpos sahaja (59.5%). Kawalan memberikan nilai insiden penyakit yang
paling tinggi iaitu 100% pada minggu ke-12. Eksperimen yang dilakukan dalam
kajian ini menunjukkan bahawa rawatan dengan UPM 2340, UPM 40 dan UPM
23 boleh meningkatkan ketegaran tanaman tomato dan berkesan dalam
merangsang penindasan terhadap kejadian layu Fusarium, mencadangkan
potensinya yang berperanan sebagai kawalan biologi dalam pengurusan layu
Fusarium.
vii
ACKNOWLEDGEMENTS
All praises and thanks to almighty Allah SWT, the most merciful, for His
blessings and the strength to complete this study.
I would like to express my deep appreciation and heartfelt gratitude to my
supervisor, Prof. Dr. Sariah Meon for her invaluable advice, support,
encouragement, patience and understanding that made this study possible. Not
forgetting, my other supervisory committee members, Assoc. Prof. Dr.
Kamaruzaman Sijam and Assoc. Prof. Dr. Siti Khalijah Daud for their continuous
guidance and constructive comments in the on-going of my research work and
the preparation of my thesis.
Heartful thanks are extended to all staffs in Pathology Laboratory; Mr.
Shamsudin, Mr. Johari, Mr. Nazri, Mr. Yusoff, Mr. Gani and Mrs. Asmalina for
their advice and assistance in the preparation of materials.
Special thanks are also extended to my beloved friends, Mohd. Hailmi, Ibrahim,
Zaiton, Niza, Yasmeen and Asgar Ali for their help and moral support towards
the completion of this thesis. Thank you for willing to share my sadness and
happiness throughout the period that we had been together.
viii
I certify that an Examination Committee met on Zth ~ a y 2005 to conduct the final examination of Rozlianah Fitri bte Said on her Master of Agricultural Science thesis entitled "Effects of Trichoderma-induced Suppressive Soil on Fusarium wilt of Tomato" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The Committee recommends that the candidate be awarded the relevant degree. Members of the Examination Committee are as follows:
ZAINAL ABlDlN MlOR AHMAD, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman)
INON SULAIMAN, PhD Lecturer Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner)
WONG MU1 YUN, PhD Lecturer Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner)
NIK MOHD. MASDEK NIK HASSAN , PhD Horticultural Research Centre MARDl (External Examiner)
~ r o f e s s o r l ~ d ~ u t ) D& School of Graduate Studies Universiti Putra Malaysia
This thesis submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Agricultural Science. The members of the Supervisory Committee are as follows:
SARIAH MEON, PhD Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman)
KAMARUZAMAN SIJAM, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Member)
SIT1 KHALIJAH DAUD, PhD Associate Professor Faculty of Science Universiti Putra Malaysia (Member)
AlNl IDERIS, PhD ProfessorIDean School of Graduate Studies Universiti Putra Malaysia
Date: I 1 AUG 2005
DECLARATION
1 hereby declare that the thesis is based on my original work except for quotations and citations, which have been duly acknowledged. I also declare that it has not been previously or concurrently submitted for any other degree at UPM or other institutions.
ROZLIANAH FlTRl BTE SAID
Date: 2 o / o t / 0 5
xii
TABLE OF CONTENTS
Page
DEDICATION ABSTRACT ABSTRAK ACKNOWLEDGEMENTS APPROVAL DECLARATION LlST OF TABLES LlST OF FIGURES LlST OF ABBREVIATIONS
CHAPTER
INTRODUCTION
LITERATURE REVIEW 2.1 Tomato Plant 2.2 Fusarium Diseases of Tomato 2.3 Fusarium Wilt of Tomato
2.3.1 Description of Pathogen 2.3.2 Symptoms
2.4 Fusarium Crown Rot 2.4.1 Description of Pathogen 2.4.2 Symptoms
2.5 Foot Rot of Tomato 2.5.1 Description of Pathogen 2.5.2 Symptoms
2.6 Molecular Assays-The Use of RAPD-PCR 2.7 Control of Fusarium Diseases on Tomato
2.7.1 Cultural Control 2.7.2 Chemical Control 2.7.3 Biological Control
2.8 Compost as Food Source for Biocontrol Agents 2.9 Disease Suppressive Compost
MATERIALS AND METHODS 3.1 Collection of Samples 3.2 Isolation of Fusarium spp. 3.3 Characterization and Identification of Fusarium spp.
3.3.1 Cultural and Morphological Analysis 3.3.2 Molecular Characterization as Expressed by
RAPD-PCR
ii iii v viii X
xii XV xvi xix
... X l l l
Pathogenicity Testing 3.4.1 Disease Incidence and Symptom Development 3.4.2 Histopathological Responses In-vitro Evaluation on the Biological Activities of Trichodenna Isolates Against Fusarium sp. 3.5.1 Dual Culture Test Preparation of lnoculants 3.6.1 Preparation of Trichodema lnoculants 3.6.2 Preparation of Fusarium lnoculants 3.6.3 Preparation of Trichodenna-Induced Suppressive
Soil Effects of Suppressive Soil on Plant Growth and Disease Suppression 3.7.1 Growth Responses of Tomato to Trichodenna
lnoculants Proliferation and Establishment of Trichodenna in the Rhizosphere and on Roots of Tomato 3.8.1 Colony Forming Units (Cfu) of Trichoderma in
Rhizosphere 3.8.2 Colony Forming Units (Cfu) of Trichodema on
Roots Statistical Analysis
RESULTS AND DISCUSSION 4.1 Isolation of Fusarium spp. from Tomato 4.2 Characterization and Identification of Fusarium spp.
4.2.1 Cultural and Morphological Analysis 4.2.2 Variation Between and Within Fusarium spp.
Aggregates as Expressed by DNA Polymorphism Pathogenicity Testing 4.3.1 Histopathological Responses Evaluation on the Biological Activities of Trichodenna Isolates Against Fusarium oxysporum f. sp. lycopersici Effects of Trichodenna-Induced Suppressive Soil on Growth of Tomato Disease Suppression Proliferation and Establishment of Trichoderma in the Rhizosphere and on Roots of Tomato
GENERAL DISCUSSION AND CONCLUSION
REFERENCES APPENDICES BIODATA OF THE AUTHOR
xiv
LIST OF TABLES
Table
3.1
Page
Twenty 10-mer primers used in initial screening of Fusarium spp. DNA.
Treatments in assessing the effect of "induced disease suppressiven soil on growth and suppression of Fusarium wilt on tomato. 3.14
Fusarium isolates isolated from stems and roots of tomato on FSM medium. 4.2
Cultural and morphological characteristics of Fusarium oxysponrm on PDA.
Cultural and morphological characteristics of Fusarium solani on PDA. 4.7
Area Under Disease Progress Curve (AUDPC) and epidemic rate of F. oxysporum (MI isolate) on Baccarat 322 and Cherry tomato, six weeks after inoculation. 4.19
Effect of Trichodena-induced suppressive soil on flower initiation of tomato plants grown in FOL infested and non- infested soil, four weeks after transplanting.
Effect of Trichodena-induced suppressive soil on average number and total fresh weight (g) of fruits in the FOL non- infested soil at week 12.
Effect of Trichodema-induced suppressive soil on average fruit diameter (crn) and total soluble solids (TSS) in the FOL non-infested soil at week 12. 4.43
Effect of Trichoderma-induced suppressive soil on average number and total fresh weight (g) of fruits in the FOL infested soil at week 12.
Effect of Trichodema-induced suppressive soil on average fruit diameter (cm) and total soluble solids (TSS) in the FOL infested soil at week 12. 4.45
Area Under Disease Progress Cuwe (AUDPC) and epidemic rate of Fusarium wilt under different treatments. 4.49
LIST OF FIGURES
Figure
4.la
Page
Cultural and morphological appearances of an isolate (MI) of Fusarium oxysporum on PDA.
Cultural and morphological appearances of an isolate (R18) of Fusarium solani on PDA.
RAPD banding profile of 22 Fusarium Isolates Using Primer OPC-11.
RAPD banding profile of 22 Fusarium Isolates Using Primer OPC-15.
RAPD banding profile of 22 Fusarium lsolates Using Primer OPC-18.
Dendrogram based on RAPD-PCR profiles generated by UPGMA analysis showing the genetic similarity among Fusarium isolates with primers OPC-I 1, OPC-15 and OPC-18.
Infected tomato plant showing development of foliar- associated symptoms of Fusarium wilt of tomato on cultivar Baccarat 322 caused by Fusarium oxysporum f. sp. lycopersici.
Disease development on tomato seedlings cultivar Baccarat 322 and Cherry inoculated with F. oxyspomm (M1 isolate), based on foliar-associated symptoms.
Reisolation of the infected root and stem tissues of cultivar Baccarat 322 on Fusarium selective media (FSM) produced pathogenic form of Fusarium oxysponrm f. sp. lycopersici.
Development of brown ring in the area of the vascular bundles at the stem base of infected tomato plant cultivar Baccarat 322 (arrow).
Brown discoloration in the vascular system progressing into the upper part of the stem (arrow).
Transverse section of healthy stem of tomato showing intact - xylem (X) and phloem (P) vessels. 4.22
xvi
Transverse section of infected stem of tomato showing distribution of fungal mass (FM) in the xylem vessels.
Presence of tyloses (T) in main xylem vessels.
Dual culture test: Showing formation of inhibition zone (arrow).
Effect of Trichoderma-induced suppressive soil on mean height of tomato in the FOL non-infested soil.
Effect of Trichoderma-induced suppressive soil on height of tomato in the FOL non-infested soil at six weeks after treatment.
Effect of Trichodenna-induced suppressive soil on leaf fresh weight (A) and dry weight (B) of tomato plants in the FOL non-infested soil at 12 weeks after treatment.
Effect of Trichodenna-induced suppressive soil on root fresh weight (A) and dry weight (B) of tomato plants in the FOL non-infested soil at 12 weeks after treatment.
Effect of Trichodema-induced suppressive soil on root length of tomato plants in the FOL non-infested soil at 12 weeks after treatment. 4.31
Effect of Trichoderma-induced suppressive soil on root growth of tomato in the FOL non-infested soil at week 12. 4.31
Effect of Trichoderma-induced suppressive soil on mean height of tomato in the FOL infested soil.
Effect of Trichodema-induced suppressive soil on height of tomato in the FOL infested soil at six weeks after treatment. 4.34
Effect of Trichoderma-induced suppressive soil on leaf fresh weight (A) and dry weight (B) of tomato plants in the FOL infested soil at 12 weeks after treatment.
Effect of Trichoderma-induced suppressive soil on root fresh weight (A) and dry weight (6) of tomato plants in the FOL infested soil at 12 weeks after treatment.
Effect of Trichoderma-induced suppressive soil on root length of tomato plants in the FOL infested soil at 12 weeks after treatment.
xvii
Effect of Trichodema-induced suppressive soil on root growth of tomato in the FOL infested soil at week 12.
Flowering of tomato plants grown with the Trichodenna- induced suppressive soil observed at week four after
'
transplanting.
Fruit diameter at week 12 in the FOL non-infested soil.
Fruit diameter at week 12 in the FOL infested soil.
Effect of different treatments (TI -T5) on the development of Fusarium wilt on tomato.
Infected tomato plants showing development of foliar -associated symptoms of Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici. 4.50
Internal symptom of Fusarium wilt in infected tomato plants.
Trichodema population in the rhizosphere, root tips and middle root sections of tomato within treatments grown in FOL non-infested soil at 12 weeks after inoculation.
Trichodenna population in the rhizosphere, root tips and middle root sections of tomato within treatments grown in FOL infested soil at 12 weeks after inoculation. 4.55
Trichodema population in the rhizosphere, root tips and middle root sections of tomato grown in FOL non-infested soil at 12 weeks after inoculation.
Trichodenna population in the rhizosphere, root tips and middle root sections of tomato grown in FOL infested soil at 12 weeks after inoculation.
xviii
LIST OF ABBREVIATIONS
AUDPC bp cfu CRD CTAB Dl DNA EDTA FA0 FOL FSM IPM kb LCB MBC M mM mtDNA ng NPK OPC % OC PCR PDA PDB PlRG PSM RAPD RFLP SDS SPP Taq TME TSS UPM UPM 23 UPM 40 UPM 2340 Pm PI vlv wlw wt
Area Under Disease Progress Curve base pair colony forming unit Complete Randomized Design Cetyltrimethyl ammonium bromide Disease Incidence Deoxyribonucleic acid Ethylenediaminetetra-acetic acid Food and Agriculture Organization Fusatium oxysporum f. sp. lycopersici Fusariurn Selective Medium Integrated Pest Management kilo-base pair Lactophenol Cotton Blue Methyl bromide chloropicrin Molar millimolar mitochondria1 DNA nanogram Nitrogen, Phosphorus, Potassium Oligo-nucleotide Purification Column Primers percent degree Celsius Polymerase Chain Reaction Potato Dextrose Agar Potato Dextrose Broth Percentage Inhibition of Radial Growth Phosphate Solubilizing Microorganisms Random Amplified Polymorphic DNA Restriction Fragment Length Polymorphism Sudden Death Syndrome spesies Thermus aquaticus Trichodenna Selective Medium Total Soluble Solids Universiti Putra Malaysia Trichodema virens Trichodema harzianum Mixture of UPM 23 and UPM 40 micrometer microliter volume per volume weight per weight weight
xix
CHAPTER 1
INTRODUCTION
Tomato is the second most commonly grown vegetable crop in the world, potato
being number one. Per capita fresh market tomato consumption continue to
increase in much of the world. A long-term medical study has revealed that
individuals who consume either fresh tomato or processed tomato products on a
regular basis are less likely to have some forms of cancer than those who do not
(Giovannucci, 1999; Agarwal and Rao, 2000). Tomato is rich in vitamin A and C
and contains an antioxidant, lycopene. However, the demands for high quality
and safe produce (pesticide-free) posses major challenges for agricultural
research.
Nowadays, demand for tomatoes has increased substantially. Based on the
Food and Agriculture Organization (FAO) of the United Nations in 1994, tomato
fruit for the fresh market and processing is produced worldwide on
approximately 2.8 million hectares (ha). In Malaysia, the production of tomato
was reported as 10, 000 million ton in 2001.
The tomato plant is widely adapted to diverse environments. It is a soil-
exhausting feeder and unless the soil is well supplied with plant food the plant
will not yield satisfactorily. Tomatoes should be planted in fertile well-drained
soil that is high in organic matter. They also require plenty of water but not
excessive because tomato roots will not function under waterlogged (anaerobic)
conditions. When the moisture level surrounding the roots is too high, epinasty,
poor growth, fewer flowers and lower fruit set occur. Fruit disorders such as fruit
cracking will occur when water availability is inconsistent (Peets and Willits,
1 995).
In Malaysia, production of tomato tends to be more successful in highland area,
primarily because of the mild temperature. Therefore, large-scale tomato
cultivation was presently carried out in Cameron Highlands. A satisfactory crop
of top-grade tomatoes can only be obtained from well-nourished plants that are
free from diseases. This has prompted the utilization of soilless culture systems
using non-soil materials or agro-wastes compost preparation for optimization of
nutrients and plant growth. Utilization of these potting mixes are considered
environmentally sustainable, and has attracted interest among research
scientists and horticulturists.
The production of tomato is also being threatened by the wide spread of
different Fusarium-associated diseases. Fusarium oxysporum f. sp. lycopersici
is a fungal pathogen commonly associated with wilt of tomato. Other Fusarium
related diseases on tomatoes are Fusarium crown rot caused by Fusarium
oxysporum f. sp. radicis-lycopersici and foot rot of tomato caused by Fusarium
solani (Nunez and Davis, 2000). Fusarium-associated diseases of tomato has
not been extensively studied in this country. Correct identification of the causal
pathogen should be carried out to enable formulation of effective strategy for
disease management.
Methods are lacking to differentiate among strains within Fusarium species or to
determine variability and abundance of strains in natural ecosystem. Different
species or strains may vary in their ability to cause diseases on tomatoes. It is
not always possible to get an accurate and reliable identification of fungi by
using morphological characters. Identification of intraspecific elements are
difficult and more often impossible (Mills, 1994). Recently a number of
techniques comprised biochemical and molecular methods have been
developed. These include intracellular isozyme and DNA-base method:
Restriction Fragment Length Polymorphism (RFLP) analysis, DNA fingerprintin , 9 Polymerase Chain Reaction (PCR) and DNA sequence analysis. The most
rapidly used DNA-based method is PCR, meanwhile Random amplified
polymorphic DNA (RAPD) technique incorporates PCR technique. It is a method
based on incorporation of single arbitrary primers and proved to be able to
distinguish variations within species.
Resistant cultivars have been the most effective means of controlling Fusarium
wilt (Beckman, 1987). However, new races of the pathogen have appeared that
overcome resistance in grown cultivars (Tello - Marquina and Lacasa, 1988).
Methyl bromide chloropicrin (MBC) has also been used as chemical control of
Fusarium wilt. However, the implication in soil and water pollution proved that
MBC is an ozone depletor (Ristaino and Thomas, 1997). Therefore, new
methods have to be developed to control Fusarium wilt on tomato.
One of the alternatives is through the use of suppressive soil. Suppressive soil
is referred to soils in which disease development is suppressed, even when the
pathogen is present with a susceptible host (Schneider, 1984). Soil
suppressiveness could be due to soil physical and chemical characteristics
and/or microbial activity. Soil suppressiveness can further be 'induced' by
inoculating antagonistic microorganisms into the soil, which inhibits the
sporulation and disease development of the pathogen.
The manipulation of the microbial communities in the rhizosphere of crop plants
for increasing yields and the biological control of diseases has been extensively
studied in field crops and greenhouse crops (Menzies and Ehret, 1997).
Introduction of Trichoderma hamianurn strains as granules and wettable powder
has shown significant results, both as plant growth promoter in several crops,
increased in the development of the root system (Ismail, 2001; Franklin, 2002)
and in the prevention against certain root diseases of greenhouse crops
(Heemart and Veenstra, 1997; Jinantana and Sariah, 1998; Ibrahim, 2005).
Combination treatment of Gliocladium virens (T. virens) and Burkholderia
cepacia resulted in improvement in disease severity and fresh weight for pepper
and fruit yield for tomato in the field (Fravel and Larkin, 1997).
This research was undertaken with the following objectives:
1. To establish the causal pathogens of Fusarium-associated disease of
tomato.
2. To study the effects of Trichoderma-induced suppressive soil for the control
of Fusarium wilt of tomato.
The hypothesis of this experiment is that Fusarium wilt of tomato caused by
Fusarium oxysporum f. sp. lycopersici can be controlled by using Trichoderma-
induced suppressive soil.
CHAPTER 2
LITERATURE REVlRN
2.1 Tomato Plant
Tomato belongs to the genus Lycopersicon L. esculentum (Mill.) that is grown
for its edible fruits. Tomato is classified as below:
Division : Anthophyta
Class : Dicotyledons
: Solanaceae
: Lycopersicon esculentum Mill
Family
Genus (Jones, 1999)
Tomato, in the past known as 'Golden Apple', is a valuable raw material for a
wide range of processed foods including canned tomato juice, canned tomato
whole or slice and tomato puree. It is believed to have originated in the coastal
strip of the western South America, from the equator to about 30' latitude south
(Taylor, 1 986).
The botanical classification of tomato had an interesting history, first being
placed in the genus Solanum lycopersicon. However, this designation was
changed to Lycopersicon esculentum, in which Lycopersicon is derived from the