Abstract
Abstract Leaf rust is a major biotic factor affecting wheat yield globally. However, the visual scoring technique to assess fungal disease in breeding programs requires significant expert manual labor and time. Unmanned aerial systems have the potential to scan large acreage in a short time for disease screening. An experiment was conducted at College Station and Castroville, TX, in 2018–2019 and 2019–2020 to assess the performance of normalized difference vegetation index (NDVI), normalized difference red edge index (NDRE), and green chlorophyll index (GCI) in detecting leaf rust infection. Other measurements included proximal canopy temperature, grain yield, and visual screening for infection type and severity. A significant positive relationship ( p < 0.001; R 2 = 0.42–0.62) of grain yield with all three vegetation indices (VIs) was observed in mid‐April 2019 at College Station. At College Station, the highest leaf rust severity coincided with the senescence stage in mid‐April 2020. No relationship between the VIs and grain yield was observed. In mid‐April 2020, when the leaf rust infection was high, the VIs showed a significant negative relationship ( p < 0.05; R 2 = 0.27) with grain yield at Castroville. All three VIs showed a significant linear negative relationship with canopy temperature at College Station ( p < 0.05; R 2 = 0.3–0.34) and Castroville ( p < 0.001; R 2 = 0.52–0.54) in mid‐April 2020. At high leaf rust severity, the repeatability of GCI was less than NDVI and NDRE at both locations in 2019 and 2020. These results may differ if multiple factors affect winter wheat simultaneously.
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Claims 7
Claim · model-written summary
Grain yield was positively related to all three vegetation indices at College Station in April 2019.
- Taxon
- wheat
Triticum aestivumt0 - Outcome
- grain yielde0
- Direction
- positivee0
- Value
- R 2 = 0.42–0.62e0
- Qualifier
- all three vegetation indices (VIs)e0
- Setting
- College Statione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A significant positive relationship ( p < 0.001; R 2 = 0.42–0.62) of grain yield with all three vegetation indices (VIs) was observed in mid‐April 2019 at College Station.”
t0“wheat leaf rust”
Claim · model-written summary
Highest leaf rust severity coincided with senescence at College Station in April 2020.
- Taxon
- wheatTriticum aestivumt0
- Organ / stage
- senescence stagee0
- Outcome
- leaf rust severitye0
- Direction
- higheste0
- Setting
- College Statione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At College Station, the highest leaf rust severity coincided with the senescence stage in mid‐April 2020.”
t0“wheat leaf rust”
Claim · model-written summary
Vegetation indices showed no relationship with grain yield at College Station in April 2020.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- grain yielde0
- Direction
- No relationshipe0
- Qualifier
- VIse0
- Setting
- College Statione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No relationship between the VIs and grain yield was observed.”
e1“At College Station, the highest leaf rust severity coincided with the senescence stage in mid‐April 2020.”
t0“wheat leaf rust”
Claim · model-written summary
Vegetation indices had a negative relationship with yield at Castroville under high leaf rust infection.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- grain yielde0
- Direction
- negativee0
- Value
- R 2 = 0.27e0
- Qualifier
- VIse0
- Setting
- Castrovillee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the VIs showed a significant negative relationship ( p < 0.05; R 2 = 0.27) with grain yield at Castroville.”
t0“wheat leaf rust”
Claim · model-written summary
Vegetation indices had a negative relationship with canopy temperature at College Station.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- canopy temperaturee0
- Direction
- negativee0
- Value
- R 2 = 0.3–0.34e0
- Qualifier
- All three VIse0
- Setting
- College Statione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All three VIs showed a significant linear negative relationship with canopy temperature at College Station ( p < 0.05; R 2 = 0.3–0.34) and Castroville ( p < 0.001; R 2 = 0.52–0.54) in mid‐April 2020.”
t0“wheat leaf rust”
Claim · model-written summary
Vegetation indices had a negative relationship with canopy temperature at Castroville.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- canopy temperaturee0
- Direction
- negativee0
- Value
- R 2 = 0.52–0.54e0
- Qualifier
- All three VIse0
- Setting
- Castrovillee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All three VIs showed a significant linear negative relationship with canopy temperature at College Station ( p < 0.05; R 2 = 0.3–0.34) and Castroville ( p < 0.001; R 2 = 0.52–0.54) in mid‐April 2020.”
t0“wheat leaf rust”
Claim · model-written summary
At high rust severity, GCI repeatability was lower than NDVI and NDRE at both locations.
- Taxon
- wheatTriticum aestivumt0
- Outcome
- repeatability of GCIe0
- Direction
- less thane0
- Comparator
- NDVI and NDREe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At high leaf rust severity, the repeatability of GCI was less than NDVI and NDRE at both locations in 2019 and 2020.”
t0“wheat leaf rust”