Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen

Rice blast disease caused by Pyricularia oryzae is one of the major diseases of rice in Sarawak, Malaysian Borneo. Unfortunately, the documentation and characterization of P. oryzae in Sarawak, resistance of Sarawak rainfed lowland landraces against P. oryzae and crucial information on the populatio...

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Main Author:	NOR AIN, HUSSIN
Format:	Thesis
Language:	English
Published:	2021
Subjects:	Q Science (General) QK Botany QR Microbiology S Agriculture (General)
Online Access:	http://ir.unimas.my/id/eprint/35665/4/Nor%20Ain.pdf
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spelling	my-unimas-ir.356652023-04-10T07:46:10Z Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen 2021 NOR AIN, HUSSIN Q Science (General) QK Botany QR Microbiology S Agriculture (General) Rice blast disease caused by Pyricularia oryzae is one of the major diseases of rice in Sarawak, Malaysian Borneo. Unfortunately, the documentation and characterization of P. oryzae in Sarawak, resistance of Sarawak rainfed lowland landraces against P. oryzae and crucial information on the population genetics of P. oryzae in the Sarawak paddy fields are still lacking. This study aims to: 1) isolate and characterize rice blast fungus from infected paddy leaves collected from four divisions in Sarawak, viz, Miri, Sri Aman, Serian and Kuching, 2) screen the selected Sarawak lowland rice landraces (Bubuk, Pandan, Semanggang, Bario (Bintung), Entangor, Entaba (Lembut), Brunei, Bario Hitam, Perintah, Sebuti, Bario Putih, Sabak Hitam, Kuning, Rendah and Saga) for resistance against different isolates of P. oryzae at seedling stage and 3) analyse the genetic relatedness of P. oryzae in Sarawak with isolates from Peninsular Malaysia. Fifteen succeeded isolates were pre-identified as P. oryzae by morphological characteristics of spores, followed by verification through internal transcribed spacer (ITS) sequence. The isolates were evaluated for morphological characteristics, growth rate and sporulation rate, which were grown on six types of media, oatmeal agar (OMA), potato dextrose agar (PDA), malt extract agar (MEA), cornmeal agar (CMA), rice agar (RA) and barley agar (BA). Morphological characterization showed that the colony surface of the different isolates varied from smooth and fluffy to rough and flattened mycelia; some were with the present of concentric rings and some with aerial mycelia. There were no morphological characters that are unique to a specific location. The growth rate and sporulation rate of each isolate varied based on types of media used. In general, among the six media, four media, viz; OMA, PDA, CMA and BA were found favourable for mycelial growth and sporulation for most of the isolates. Disease test screening were done by inoculating 15 lowland rice landraces against five different isolates of P. oryzae, viz; isolate POK3, POK6, POS2, POMI1 and POSA2. The results showed that all rice landraces were resistance against four P. oryzae isolates namely, POK3, POK6, POS2 and POMI1. Nine rice landraces showed mild resistance against isolate POSA2. Isolate specificity resistance was observed. Phylogenetic tree analysis based on Internal transcribed spacer (ITS) region was constructed by using maximum-likelihood method involving eight isolates from Sarawak and seventeen different isolates from five different states in Peninsular Malaysia. The results found that all isolates from Sarawak except isolate POSA1 were genetically related to isolates from Peninsular Malaysia. Universiti Malaysia Sarawak (UNIMAS) 2021 Thesis http://ir.unimas.my/id/eprint/35665/ http://ir.unimas.my/id/eprint/35665/4/Nor%20Ain.pdf text en validuser masters Universiti Malaysia Sarawak (UNIMAS) Faculty of Resource Science and Technology
institution	Universiti Malaysia Sarawak
collection	UNIMAS Institutional Repository
language	English
topic	Q Science (General) QK Botany QR Microbiology S Agriculture (General)
spellingShingle	Q Science (General) QK Botany QR Microbiology S Agriculture (General) NOR AIN, HUSSIN Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
description	Rice blast disease caused by Pyricularia oryzae is one of the major diseases of rice in Sarawak, Malaysian Borneo. Unfortunately, the documentation and characterization of P. oryzae in Sarawak, resistance of Sarawak rainfed lowland landraces against P. oryzae and crucial information on the population genetics of P. oryzae in the Sarawak paddy fields are still lacking. This study aims to: 1) isolate and characterize rice blast fungus from infected paddy leaves collected from four divisions in Sarawak, viz, Miri, Sri Aman, Serian and Kuching, 2) screen the selected Sarawak lowland rice landraces (Bubuk, Pandan, Semanggang, Bario (Bintung), Entangor, Entaba (Lembut), Brunei, Bario Hitam, Perintah, Sebuti, Bario Putih, Sabak Hitam, Kuning, Rendah and Saga) for resistance against different isolates of P. oryzae at seedling stage and 3) analyse the genetic relatedness of P. oryzae in Sarawak with isolates from Peninsular Malaysia. Fifteen succeeded isolates were pre-identified as P. oryzae by morphological characteristics of spores, followed by verification through internal transcribed spacer (ITS) sequence. The isolates were evaluated for morphological characteristics, growth rate and sporulation rate, which were grown on six types of media, oatmeal agar (OMA), potato dextrose agar (PDA), malt extract agar (MEA), cornmeal agar (CMA), rice agar (RA) and barley agar (BA). Morphological characterization showed that the colony surface of the different isolates varied from smooth and fluffy to rough and flattened mycelia; some were with the present of concentric rings and some with aerial mycelia. There were no morphological characters that are unique to a specific location. The growth rate and sporulation rate of each isolate varied based on types of media used. In general, among the six media, four media, viz; OMA, PDA, CMA and BA were found favourable for mycelial growth and sporulation for most of the isolates. Disease test screening were done by inoculating 15 lowland rice landraces against five different isolates of P. oryzae, viz; isolate POK3, POK6, POS2, POMI1 and POSA2. The results showed that all rice landraces were resistance against four P. oryzae isolates namely, POK3, POK6, POS2 and POMI1. Nine rice landraces showed mild resistance against isolate POSA2. Isolate specificity resistance was observed. Phylogenetic tree analysis based on Internal transcribed spacer (ITS) region was constructed by using maximum-likelihood method involving eight isolates from Sarawak and seventeen different isolates from five different states in Peninsular Malaysia. The results found that all isolates from Sarawak except isolate POSA1 were genetically related to isolates from Peninsular Malaysia.
format	Thesis
qualification_level	Master's degree
author	NOR AIN, HUSSIN
author_facet	NOR AIN, HUSSIN
author_sort	NOR AIN, HUSSIN
title	Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
title_short	Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
title_full	Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
title_fullStr	Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
title_full_unstemmed	Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen
title_sort	characterization of pyricularia oryzae and screening the qualitative resistance of sarawak rainfed lowland rice landraces against the pathogen
granting_institution	Universiti Malaysia Sarawak (UNIMAS)
granting_department	Faculty of Resource Science and Technology
publishDate	2021
url	http://ir.unimas.my/id/eprint/35665/4/Nor%20Ain.pdf
_version_	1783728460813828096

Characterization of Pyricularia oryzae and Screening the Qualitative Resistance of Sarawak Rainfed Lowland Rice Landraces Against the Pathogen

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