TY  - BOOK
AU  - Rashmi C R
AU  - Gokulapalan C (Guide)
TI  - Epidemiology and management of false smut of rice (Oryza sativa L) in Kerala 
U1  - 632.3 
PY  - 2014///
CY  - Vellayani
PB  - Department of Plant Pathology, College of Agriculture
KW  - plant pathology
N1  - PhD
N2  - The study entitled 'Epidemiology and management of false smut of rice 
(Oryza saliva L.) in Kerala' was conducted during the period 2010-2013 at College 
of Agriculture, Vellayani, Trivandrum and the field experiments and varietal 
evaluation trials were carried out at the Regional Agricultural Research Station, 
Pattambi, Palakkad, Rice Research Station, Moncompu, Alappuzha and at Farmers 
fields at Vilayur (Palakkad) and Chambakkulam (Alappuzha). 
The results of the surveys conducted at Alappuzha and Palakkad indicated 
that maximum disease was observed at the upper Kuttanad area of Alappuzha. A new 
collateral host for the pathogen, Oryza spontaneum was observed at Alappuzha 
during the survey. Isolation of the pathogen was made from the samples collected 
during the survey. The method of isolation of the pathogen was standardized. Surface 
sterilization of smut balls with 0.1 % HgCb for 3.5-4 minutes followed by three serial 
washings with sterile water and dusting of the chlamydospores over YPPDA, and 
pure culturing after observation under a light microscope after 24 hrs was the method 
devised for isolation. Ideal conditions for culturing of the fungus under in vitro 
conditions were found to be the use of YPPDA medium of pH 6.5 at 28°C under full 
darkness. An indigenous medium viz., rice extract sucrose agar was developed for the 
culturing of the pathogen. 
The pathogen, Ustilaginoidea virens was observed to be producing smut balls 
and chlamydospores in culture similar to that produced under field conditions. 
Stromatic heads of the fungus was observed under in vitro conditions for the first 
time in India. Sequencing of the ITS region of pathogen gave 100% similarity with 
the known sequences of U. virens on BLAST analysis and thus the pathogen was 
conformed to be U. virens. The pathogen isolates were identified and deposited at 
ITCC, New Delhi, and the accession numbers ITCC-7335 (Pattambi, Palakkad) and 
ITCC-7334 (Moncompu, Alappuzha)were obtained for the isolates. 
 
Laboratory trials revealed the efficacy of five chemical fungicides, different 
species of Trichoderma and three bacterial strains for suppression of the pathogen in 
vitro. 
Correlation studies on the influence of weather parameters on the 
development of the disease revealed that the disease was negatively correlated with 
the minimum temperature during SO % flowering. Results of the survival studies of 
the pathogen revealed that the smut balls of the pathogen can survive for eight 
months at room temperature. At field level, the fungus was found to be surviving on 
the ratoon rice emerged from the stubbles of the previous crop. 
Under the varietal evaluation trials conducted at Alappuzha and Palakkad, the 
varieties Vaishak and Harsha were found resistant to the disease and the varieties 
PTB 10 and Makom were moderately resistant. The varieties, Uma, Remanika, Gouri 
and Bhagya were the most susceptible ones. RAPD profiling of the resistant and 
susceptible varieties with 10 random primers showed polymorphism with five 
primers OPK-I4, OPG-I8, OPC-IS, OPB-IO and OPD-I8. 
Field trials conducted at Alappuzha and Palakkad showed that spraying of 
Propiconazole 12Sg a.i./7 SO L or TebuconazoleO.I87 S kg a.i./SOO L or Copper 
Hydroxidel000 g a.i./7S0 L or Pseudomonas flourescens @ 2% of the talc based 
formulationat SO% flowering could control the disease effectively. Tebuconazole 
0.187S kg a.i./SOO L gave significant yield increase over the control. 
Biochemical studies like SDS PAGE and NA TIVE PAGE were conducted. 
SDS PAGE showed conspicuous bands of the pathogen proteins and NATIVE PAGE 
revealed increased activity of peroxidase and polyphenol oxidase on the diseased 
grams. 
Based on the research results, a management package was developed for 
effective control of the disease at the field level as follows: 1) avoiding use of paddy 
grains harvested from severely affected fields as seed material 2) avoiding continuous 
 
cultivation of the most susceptible rice varieties like, Uma, Remanika, Gouri and 
Bhagya 3) use of resistant varieties like Harsha, Vaishak or Makom 4) Weed 
management to control the collateral hosts like wild rice 5) biological control by 
spraying of Pseudomonas flourescens @ 2% of the talc based formulation at 50% 
flowering 6) spraying of Propiconazole125 g a.i./750 L or Tebuconazole 0.1875 kg 
a.i./500 L or Copper Hydroxide 1000 g a.i./750 L at 50% flowering. 


UR  - http://krishikosh.egranth.ac.in/handle/1/5810026916
ER  -