Abstract
Savary, S., Castilla, N. P., Elazegui, E A., McLaren, C. G., Ynalvez, M. A., and Teng, P. S. 1995. Direct and indirect effects of nitrogen supply and disease source structure on rice sheath blight spread. Phytopathology 85~959-965. Effects of nitrogen and type of disease source on focal expansion of rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments. Four disease source types, represented by inoculated individual hills at the center of experimental plots, were obtained by combining two inoculum doses with two heights of inoculation in the canopy. Compared with the low inoculum dose, there was a small but significant increase of disease severity on source hills with the higher inoculum dose, and no disease developed on noninoculated controls. Severity on the sheaths was higher on hills inoculated at the sheath level than on hills inoculated at the leaf level. Conversely, leaf severity was higher on hills inoculated at the leaf level than on hills inoculated at the sheath level. Increased nitrogen supply increased host plant tissue contacts (leaf-to-leaf and leaf-to-sheath), increased the capacity of the canopy to retain moisture, and increased the leaf nitrogen content in both experiments. The size of sheath blight foci was much larger in the rainy (3,000 to 30,000 cmz) than in the dry (250 to 1,100 cm2) season. In both experiments, foci expanded most rapidly in the high nitrogen supply (120 kg per ha) level compared with medium (80 kg per ha) and no nitrogen supply. Positioning of inoculum in the upper layer of the canopy (leaf level) on source hills resulted in faster spread of foci than positioning in the lower layer (sheath level). Multiple regression and path coefficient analyses suggested that nitrogen drives focal expansion in sheath blight essentially via indirect effects: increased tissue contacts in the canopy and higher leaf wetness.
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Claims 11
Claim · model-written summary
A higher inoculum dose gave a small but significant increase in sheath blight severity on source hills compared with the low dose
- Taxon
- rice
Oryza sativae1 - Treatment
- higher inoculum dosee2
- Interactor
- Rhizoctonia solani
Rhizoctonia solanie1pathogen - Outcome
- disease severitye2
- Direction
- increasee2
- Qualifier
- small but significante2
- Comparator
- low inoculum dosee2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Compared with the low inoculum dose, there was a small but significant increase of disease severity on source hills with the higher inoculum dose”
Claim · model-written summary
No sheath blight developed on noninoculated controls
- Taxon
- riceOryza sativae1
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- diseasee2
- Comparator
- noninoculated controlse2
- Setting
- two field experimentse1
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“no disease developed on noninoculated controls”
Claim · model-written summary
Sheath severity was higher on hills inoculated at the sheath level than on hills inoculated at the leaf level
- Taxon
- riceOryza sativae1
- Organ / stage
- sheathse2
- Treatment
- hills inoculated at the sheath levele2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- severitye2
- Direction
- highere2
- Comparator
- hills inoculated at the leaf levele2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Severity on the sheaths was higher on hills inoculated at the sheath level than on hills inoculated at the leaf level”
Claim · model-written summary
Leaf severity was higher on hills inoculated at the leaf level than on hills inoculated at the sheath level
- Taxon
- riceOryza sativae1
- Organ / stage
- leafe2
- Treatment
- hills inoculated at the leaf levele2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- leaf severitye2
- Direction
- highere2
- Comparator
- hills inoculated at the sheath levele2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Conversely, leaf severity was higher on hills inoculated at the leaf level than on hills inoculated at the sheath level”
Claim · model-written summary
Increased nitrogen supply increased host plant tissue contacts between leaves and sheaths
- Taxon
- riceOryza sativae1
- Treatment
- Increased nitrogen supplye2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- host plant tissue contactse2
- Direction
- increasede2
- Qualifier
- leaf-to-leaf and leaf-to-sheathe2
- Setting
- two field experimentse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Increased nitrogen supply increased host plant tissue contacts (leaf-to-leaf and leaf-to-sheath)”
Claim · model-written summary
Increased nitrogen supply increased the capacity of the canopy to retain moisture
- Taxon
- riceOryza sativae1
- Treatment
- Increased nitrogen supplye2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- capacity of the canopy to retain moisturee2
- Direction
- increasede2
- Setting
- two field experimentse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Increased nitrogen supply increased host plant tissue contacts (leaf-to-leaf and leaf-to-sheath), increased the capacity of the canopy to retain moisture”
Claim · model-written summary
Increased nitrogen supply increased the leaf nitrogen content
- Taxon
- riceOryza sativae1
- Treatment
- Increased nitrogen supplye2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- leaf nitrogen contente3
- Direction
- increasede3
- Setting
- two field experimentse1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Increased nitrogen supply increased host plant tissue contacts (leaf-to-leaf and leaf-to-sheath), increased the capacity of the canopy to retain moisture”
e3“increased the leaf nitrogen content in both experiments”
Claim · model-written summary
Sheath blight foci were much larger in the rainy season than in the dry season
- Taxon
- RiceOryza sativat0
- Outcome
- size of sheath blight focie2
- Direction
- much largere2
- Value
- 3,000 to 30,000 cmze2
- Comparator
- dry (250 to 1,100 cm2) seasone2
- Setting
- rainye2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Rice Sheath Blight Spread”
e2“The size of sheath blight foci was much larger in the rainy (3,000 to 30,000 cmz) than in the dry (250 to 1,100 cm2) season”
Claim · model-written summary
Placing inoculum at the upper canopy layer (leaf level) on source hills gave faster foci spread than placing it at the lower layer (sheath level)
- Taxon
- riceOryza sativae1
- Treatment
- Positioning of inoculum in the upper layer of the canopy (leaf level) on source hillse2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- spread of focie2
- Direction
- fastere2
- Comparator
- positioning in the lower layer (sheath level)e2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Positioning of inoculum in the upper layer of the canopy (leaf level) on source hills resulted in faster spread of foci than positioning in the lower layer (sheath level)”
Claim · model-written summary
Foci expanded most rapidly at the high nitrogen supply compared with medium and no nitrogen supply in both experiments
- Taxon
- riceOryza sativae1
- Treatment
- high nitrogen supply (120 kg per ha) levele2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- foci expandede2
- Direction
- most rapidlye2
- Comparator
- medium (80 kg per ha) and no nitrogen supplye2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“In both experiments, foci expanded most rapidly in the high nitrogen supply (120 kg per ha) level compared with medium (80 kg per ha) and no nitrogen supply”
Claim · model-written summary
Path analysis suggests nitrogen drives sheath blight focal expansion mainly via increased canopy tissue contacts and higher leaf wetness
- Taxon
- riceOryza sativae1
- Treatment
- nitrogene2
- Interactor
- Rhizoctonia solaniRhizoctonia solanie1pathogen
- Outcome
- focal expansione2
- Qualifier
- via indirect effects: increased tissue contacts in the canopy and higher leaf wetnesse2
- Setting
- two field experimentse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“rice sheath blight (caused by Rhizoctonia solani) were studied in. two field experiments”
e2“Multiple regression and path coefficient analyses suggested that nitrogen drives focal expansion in sheath blight essentially via indirect effects: increased tissue contacts in the canopy and higher leaf wetness”
The same questions in other papers
inoculation · Rhizoctonia solani · Oryza sativa (rice)Positive and negative results
7 papers in the same direction as this paper · 23 in the opposite direction
- positive
- positive
- positive
27 papers more in this group
See all 31 papers →nitrogen · Rhizoctonia solani · Oryza sativa (rice)Results agree
3 papers in the same direction as this paper
- negative
- negative
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.