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