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STUDIES ON INFECTION, HOST RANGE AND VARIABILITY OF Sarocladium oryzae (Sawada) W. Gams and D. Hawksworth, THE INCITANT OF SHEATH ROT OF RICE

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Title STUDIES ON INFECTION, HOST RANGE AND VARIABILITY OF Sarocladium oryzae (Sawada) W. Gams and D. Hawksworth, THE INCITANT OF SHEATH ROT OF RICE
 
Creator Yadav, Vijay Kumar
 
Contributor Thrimurty, V.S.
Kotasthane, A.S.
Thakur, M.P.
Pophaly, D.J.
Lakhera, M.L.
 
Subject Sarocladium oryzae (Sawada) W. Gams and D. Hawksworth,SHEATH ROT,RICE
Plant Pathology
 
Description The present investigations entitled “Studies on infection, host range and variability of Sarocladium oryzae (Sawada) W. Gams and D. Hawksworth, the incitant of sheath rot of rice” were conducted at the Department of Plant Pathology laboratories and mist chamber and experimental sites and glass house of the Entomology Department, for the insect related studies.
Isolation of the causal organism Sarocladium oryzae from different varieties; extent of seed borne infection in two popular varieties, Bamleshwari and Chapti; role of seed borne infection in disease development; progress of infection from seed to seedling and boot stage; the importance of infected plant debris as a source of inoculum; host range studies; impact of brown plant hopper feeding in the incidence of sheath rot; resistance in elite cultivars identified at different locality against the local virulent isolate; variability within the isolates of the pathogen; effect of medicinal plant leaves extracts on S. oryzae growth and association of any other pathogen in causing sheath rot were studied.
The isolations made from the infected sheath rot samples of the 21 varieties and 1 departmental isolate collected previously, clearly showed that the pathogen associated was S. oryzae. This was confirmed with standard reports through comparisons and pathogenicity tests.
Seed borne infection was detected in the two varieties Bamleshwari and Chapti. The component plating of husk and dehusked grain of the varieties also revealed that the per cent invasion of the fungus was more in husk as compared to endosperm and embryo (collectively the dehusked grain).
The present studies on seed borne infection and its transmission to the plant clearly revealed that infected seed plays an important role in contributing for more disease incidence. Further, the pathogen could be detected at seedlings, tillering and at early boot stages from the plants raised from infected seed, though the per cent samples recorded with positive results varied in these growth stages. The present studies also confirmed the seed transmission of the fungus.
The infected plant debris also significantly contributed for the increase in disease incidence. Most of the wild rices of O. nivara and O. sativa f. spontanea which are common in Chhattisgarh region were found to be susceptible to the S. oryzae. Similarly some weeds species such as Digitaria sanguinalis, Leersia hexandra, Elusine indica, Echinocloa spp. and Setaria glauca also showed sheath rot disease, caused by S. oryzae under natural condition. Under artificial inoculated conditions 7 weeds out of 40 tested viz., Cyperus iria, C. rotundus, C. deformis, Fimbristylis miliaces, Saccharum spontaneum, Ischaemum rugosum and Echinochloa colona showed symptoms of sheath rot.
Brown plant hopper feeding enhanced the sheath rot incidence. The injury caused at the time of feeding might have helped as a portal for the entry of S. oryzae.
The elite resistant varieties identified at different locations of the country showed susceptible reaction with a local virulent isolate. This indicates that Chhattisgarh isolates might be more virulent. Variations were observed in the isolates (22 isolates) studied for different morphological characters including spore sizes, variation to growth at three temperatures (20oC, 25oC and 30oC) and relative virulence on 4 varieties inoculated, confirming that variability exists within S. oryzae.
 
Date 2016-12-06T14:24:50Z
2016-12-06T14:24:50Z
2003
 
Type Thesis
 
Identifier 160 p.
http://krishikosh.egranth.ac.in/handle/1/89295
 
Language en
 
Format application/pdf
 
Publisher Indira Gandhi Krishi Vishwavidyalaya, Raipur