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UNIVERSITI PUTRA MALAYSIA
EFFECTS OF FOLIAR AND ROOT APPLICATION OF SILICON ON RICE BLAST FUNGUS IN MR219 RICE
FARNAZ ABED ASHTIANI
FP 2012 16
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EFFECTS OF FOLIAR AND ROOT APPLICATION OF SILICON ON RICE BLAST FUNGUS IN MR219 RICE
By
FARNAZ ABED ASHTIANI
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirements for the Degree of Master of
Agricultural Science
October 2012
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Dedication
This Thesis is dedicated to
My Most Beloved Father, Yousef
My Gracious Mother, Saphoura
My Lovely Sister, Sarvnaz
Without your love, patience, understanding, financial and
emotional support this work could never been completed.
Likewise, many faced problems during this study were a lot
ease through your compassion.
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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirement for the degree of Master of
Agricultural Science
EFFECTS OF FOLIAR AND ROOT APPLICATION OF SILICON ON RICE BLAST FUNGUS IN MR219 RICE
By
FARNAZ ABED ASHTIANI
October 2012
Chairman: Associate Professor Jugah B Kadir, PhD
Faculty : Agriculture
Rice blast caused by fungus Magnaporthe grisea (Hebert) Barr [teleomorph]
Pyricularia oryzae Cavara is among the most devastating diseases of rice
worldwide. In modern agricultural practices it is highly important to manage
diseases and pests using efficient methods with minimum harm to the
environment. Although silicon has been reported to significantly reduce foliar
diseases in crops, its application has not been widely adopted in Malaysia.
Hence studies were conducted to determine the effects of silicon on
Pyricularia oryzae. Rice variety MR219 was grown in the glasshouse and the
function of silica gel and sodium silicate in conferring resistance against
blast was investigated. Silica gel was applied to soil prior to planting (0, 60,
120, 180 g/5 kg of soil) while sodium silicate was used as foliar spray (0, 1,
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2, 3 mL/L). The treatments were arranged in a completely randomized
design with three replications. The severity of disease and silicon content of
leaves were compared between the non-amended controls and rice plants
receiving the different rates and sources of silicon. Silicon at all rates of
application significantly (α=0.05) reduced the severity of disease with the
highest reduction (75%) recorded in treatments receiving 120 g of silica gel.
The relationship between leaf blast severity (Y) and amount of silicon
applied to the plants (X) could be explained by the exponential decay curve
using equation y=Ae-bx indicating that leaf blast severity was lower with
higher rates of silicon application. Scanning Electron Microscopic
observations showed that there were two types of silicified cells on the
adaxial surface of rice leaves which included dumbbell-shaped and small
scattered silica cells. The X-ray spectra analysis demonstrated a significant
difference in weight concentration of silicon in silica cells on the leaf
epidermis between silicon treated (25.79%) and non treated plants (7.87%)
as well as among plants treated with different rates of silica gel and sodium
silicate, indicating that silicon-fertilization resulted in higher deposition of
silicon in both kinds of silica cells. Application of silicon also led to a
significant increase (25.3 g/kg) in silicon content of leaves compared to non-
treated plants (6.28 g/kg). The rate of photosynthesis of silicon treated plants
(11.98 µmolm-2s-1) was significantly higher than plants in the control group
(6.36 µmolm-2s-1). Shoot dry weight of rice plants increased significantly
(1.50 g) with silicon fertilization as compared to non-treated plants (0.90 g).
Contrast procedures indicated higher efficiency of silica gel in comparison to
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sodium silicate in almost all parameters assessed. The results suggest that
mitigated levels of disease were associated with fortification of rice leaf
epidermal cells through silicon fertilization. Although both foliar and root
application of silicon were effective in decreasing the intensity of blast,
greater effectiveness was achieved through root application. In conclusion,
the study supports the hypothesis that silicon is able to confer resistance
against blast disease. This could make silicon a useful tool for managing rice
diseases, possibly in conjunction with reduced rate of fungicide, and may
provide alternative to rice growers in areas where blast resistant cultivars
have become susceptible.
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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagi memenuhi keperluan untuk ijazah Master Sains Pertanian
KESAN APLIKASI BAJA SILIKON MELALUI PENYEMBURAN DAUN DAN AKAR TERHADAP PENYAKIT KULAT KARAH PADA PADI MR 219
Oleh
FARNAZ ABED ASHTIANI
Oktober 2012
Pengerusi: Profesor Madya Jugah B Kadir, PhD
Fakulti : Pertanian
Penyakit karah yang disebabkan oleh kulat Magnaporthe grisea (Herbert)
Barr [teleomorph] Pyricularia oryzae Cavara merupakan antara penyakit
padi paling serius di seluruh dunia. Dalam amalan pertanian moden,
pengurusan penyakit dan perosak dengan menggunakan kaedah yang
dapat memberi perlindungan kepada tumbuhan secara maksimum di
samping mengurangkan kerosakan kepada alam sekitar amat
dititikberatkan. Walaupun banyak kajian tentang silikon telah menunjukkan
pengurangan pelbagai jenis penyakit daun, namun pengunaan nutrien
tersebut masih tidak dipraktikan secara meluas di Malaysia. Dengan itu,
kajian telah dijalankan untuk mengkaji kesan silikon dari sumber yang
berlainan terhadap Pyricularia oryzae. Kajian dijalankan di rumah kaca UPM
dengan menggunakan silika gel dan sodium silikat untuk mengkaji kesan
sumber silikon yang berlainan terhadap penyakit karah pada padi varieti
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MR219. Silika gel dicampurkan dengan tanah sebelum penanaman padi
dengan kadar 0, 60, 120, 180g/5kg tanah manakala sodium silikat
disemburkan pada daun dengan kadar 0, 1, 2, 3 mL/L. Severiti penyakit dan
kandungan silika pada daun dibandingkan antara tanaman kawalan dan
tanaman yang mendapat aplikasi silikon. Kesemua aplikasi silikon (α=0.05)
dapat mengawal penyakit secara berkesan dengan pengurangan keterukan
penyakit tertinggi (75%) untuk kadar aplikasi 120g silika gel. Hubungan
antara keterukan penyakit karah (Y) dan kadar aplikasi silika pada padi (X)
dapat dirumuskan dengan ‘exponential decay curve’ dengan mengunakan
persamaan y=Ae-bx (di mana A dan b adalah pemalar dalam regresi yang
tidak linear). Cerapan melalui imbasan mikroskop elektron menunjukkan
bahawa terdapat dua jenis sel silika pada permukaan daun padi iaitu, bentuk
“dumbbell” dan taburan sel silika yang kecil. Analisis spektrum sinar-X
menunjukkan perbezaan yang signifikan bagi kepekatan berat silikon dalam
sel silika pada epidermis daun yang dirawat dengan silikon (25.79%) dan
juga tanaman kawalan (7.87%). Perbezaan yang signifikan juga boleh
diperhatikan bagi tanaman yang dirawat dengan pelbagai kadar silika gel
dan sodium silikat. Hal ini menunjukkan bahawa baja silikon menyebabkan
peningkatan kandungan silikon pada kedua-dua jenis silika sel berbanding
dengan tanaman kawalan. Berbanding dengan tanaman kawalan (6.28
g/kg), aplikasi silikon juga menyebabkan peningkatan kandungan silikon
pada daun dengan mengunakan kaedah kolorimetrik molybdenum biru.
Kadar fotosintetik padi yang dirawat dengan silikon (11.98 μmolm-2s-1) jelas
lebih tinggi berbanding tanaman kawalan (6.36 μmolm-2s-1). Berat padi yang
dikeringkan secara signifikannya meningkat (1.50g) dengan aplikasi baja
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silikon berbanding dengan tanaman kawalan (0.90g). Kaedah statistik
bandingan menunjukkan silika gel adalah lebih efektif berbanding dengan
sodium silikat dalam semua parameter yang diuji. Hasil kajian ini
mencadangkan bahawa pengurangan kadar penyakit dikaitkan dengan
kandungan silika yang tinggi dan ketahanan sel daun epidermis padi
terhadap penyakit karah. Walaupun aplikasi silikon melalui penyemburan
daun dan akar adalah berkesan, namun aplikasi silikon pada akar adalah
lebih efektif. Secara keseluruhannya, kajian ini menyokong hipotesis
bahawa silikon dapat meningkatkan daya pertahanan terhadap penyakit
karah. Hal ini menunjukkan bahawa silikon berpotensi dalam pengurusan
penyakit padi. Dalam masa yang sama, penggunaan racun kulat boleh
dikurangkan di samping menjadi sumber alternatif kepada petani di mana
kultivar padi yang rintang penyakit karah menjadi kultivar yang rentan
kepada penyakit tersebut.
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ACKNOWLEDGEMENTS
First of all I am thankful to GOD that showered me with strength and
patience during completing this marvelous study and made me worthy of
love and support of those who helped me impatiently. I would like to express
my heartfelt and deep appreciation to the chairman of my supervisory
committee Associate. Prof. Dr. Jugah Kadir for his bounteous advices and
suggestions during this study. My profound gratitude is also extended to
members of the supervisory committee, Dr. Ahmad B. Selamat for his
valuable guidance and advices on the statistical analyses and to Associate.
Prof. Dr. Ahmad Husni Mohd. Hanif for his suggestions and assistance on
the soil chemical and physical analyses. My appreciation is also extended to
Dr. Farshid Mahmodi for his helpfulness and all his valuable guidance during
this study. Special thanks to all staff of Pathology Lab., to Mr. Mohd. Yusoff
Mohd. Yassin, assistant science officer of Microbiology Lab, and to all dear
friends and labmates for their kindness and beautiful bond of helpfulness. I
also would like to express my sincere thank to Dr. Khadijah Rambe, a
wonderful friend who for always being with me whenever help is needed.
Last but not least I would like to offer my heartfelt thank to my husband
“Reza” to give me the motivation to perform to my maximum ability.
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I certify that a Thesis Examination Committee has met on 5 October 2012 to conduct the final examination of Farnaz Abed Ashtiani on her thesis entitled “Effects of Foliar and Root Application of Silicon on Rice Blast Fungus in MR219 Rice” in accordance with the Universities and University Colleges Act 1971 and the Constitution of the Universiti Putra Malaysia [P.U.(A) 106] 15 March 1998. The Committee recommends that the student be awarded the Master of Agricultural Science. Members of the Thesis Examination Committee were as follows: Kamaruzaman bin Sijam, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman) Ganesan A/L Vadamalai, PhD Senior Lecturer Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner) Abdul Shukor bin Juraimi, PhD Professor Faculty of Agriculture Universiti Putra Malaysia (Internal Examiner) Latiffah binti Zakaria, PhD Associate Professor School of Biological Sciences Universiti Sains Malaysia (External Examiner)
SEOW HENG FONG, PhD
Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia
Date: 29 November 2012
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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfillment of the requirement for the degree of Master of Agricultural Science. The members of the Supervisory Committee were as follows:
Jugah bin Kadir, PhD Associate Professor Faculty of Agriculture Universiti Putra Malaysia (Chairman) Ahmad bin Selamat, PhD Senior Consultant Fellow Faculty of Agriculture Universiti Putra Malaysia (Member) Ahmad Husni bin Mohd Haniff, PhD Associate Professor Faculty of Agriculture University Putra Malaysia (Member)
BUJANG BIN KIM HUAT, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia
Date:
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DECLARATION
I declare that the thesis is my original work except for quotations and citations which have been duly acknowledged. I also declare that it has not been previously, and is not concurrently, submitted for any other degree at Universiti Putra Malaysia or at any other institution.
FARNAZ ABED ASHTIANI
Date: 19 October 2012
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TABLE OF CONTENTS
Page
DEDICATION ii ABSTRACT iii ABSTRAK vi ACKNOWLEDGEMENTS ix APPROVAL x DECLARATION xii LIST OF TABLES xvi LIST OF FIGURES xviii LIST OF ABBREVIATIONS xx
CHAPTER
1 INTRODUCTION 1
1.1 Justification 3
1.2 Objectives 3
2 LITERATURE REVIEW 5 2.1 Rice cultivation in Malaysia 5
2.2 MR 219 rice variety 7
2.3 Rice diseases 8
2.4 Rice blast disease 8
2.4.1 Life cycle of blast disease 10
2.4.2 Leaf blast symptoms 11
2.4.3 Leaf collar symptoms 12
2.4.4 Node symptoms 12
2.4.5 Panicle and grain symptoms 12
2.5 Economic importance of blast disease 13
2.5.1 Economic importance of blast disease in Malaysia 14
2.6 Epidemiology 14
2.7 Control 15
2.7.1 Cultural management 16
2.8 Silicon 18
2.8.1 Benefits of silicon-based fertilizers 19
2.8.2 Blast suppression by Si application 23
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3 MATERIALS AND METHODS 27 3.1 Source of plant materials 27
3.2 Rice plant cultivation 28
3.3 Soil preparation 30
3.4 Silicon sources and growth condition 30
3.5 Inoculum source 31
3.6 Conidia suspension preparation 33
3.7 Plant inoculation 33
3.8 Pathogenicity test 34
3.9 Morphology and size of conidia 35
3.10 Experimental design 36
3.11 Disease severity assessment 36
3.12 Microscopy observation 37
3.13 Plant assessment 38
3.13.1 Plant height 38
3.13.2 Shoot and root dry weight 38
3.13.3 Photosynthesis measurement 39
3.13.4 Leaf temperature measurement 40
3.13.5 Determination of silicon content in leaves 41
3.13.5.1 Sample preparation 41
3.13.5.2 Pretreatment of Samples 41
3.13.5.3 Silicon determination in samples 42
3.13.5.4 Setting up standard curve 43
3.14 Data analysis 44
4 RESULTS 45 4.1 Morphology and size of Pyricularia oryzae conidia 45
4.2 Disease severity assessment 46
4.3 Microscopy observation 50
4.4 Plant assessment 56
4.4.1 Plant height 56
4.4.2 Leaf temperature 57
4.4.3 Photosynthesis rate 57
4.4.4 Shoot and root dry weight 58
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4.4.5 Silicon content in leaves 60
5 DISCUSSION 62
6 SUMMARY, CONCLUSION AND RECOMMENDATIONS FOR FUTURE REFUTURE RESEARCH 68
REFERENCES 72
APPENDICES 82 BIODATA OF STUDENT 86
LIST OF PUBLICATIONS 87