Universität zu Köln

Yu, Kang ORCID: 0000-0002-0686-6783, Leufen, Georg, Hunsche, Mauricio, Noga, Georg, Chen, Xinping and Bareth, Georg (2014). Investigation of Leaf Diseases and Estimation of Chlorophyll Concentration in Seven Barley Varieties Using Fluorescence and Hyperspectral Indices. Remote Sens., 6 (1). S. 64 - 87. BASEL: MDPI. ISSN 2072-4292

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Abstract

Leaf diseases, such as powdery mildew and leaf rust, frequently infect barley plants and severely affect the economic value of malting barley. Early detection of barley diseases would facilitate the timely application of fungicides. In a field experiment, we investigated the performance of fluorescence and reflectance indices on (1) detecting barley disease risks when no fungicide is applied and (2) estimating leaf chlorophyll concentration (LCC). Leaf fluorescence and canopy reflectance were weekly measured by a portable fluorescence sensor and spectroradiometer, respectively. Results showed that vegetation indices recorded at canopy level performed well for the early detection of slightly-diseased plants. The combined reflectance index, MCARI/TCARI, yielded the best discrimination between healthy and diseased plants across seven barley varieties. The blue to far-red fluorescence ratio (BFRR_UV) and OSAVI were the best fluorescence and reflectance indices for estimating LCC, respectively, yielding R-2 of 0.72 and 0.79. Partial least squares (PLS) and support vector machines (SVM) regression models further improved the use of fluorescence signals for the estimation of LCC, yielding R-2 of 0.81 and 0.84, respectively. Our results demonstrate that non-destructive spectral measurements are able to detect mild disease symptoms before significant losses in LCC due to diseases under natural conditions.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Yu, Kang UNSPECIFIED orcid.org/0000-0002-0686-6783 UNSPECIFIED Leufen, Georg UNSPECIFIED UNSPECIFIED UNSPECIFIED Hunsche, Mauricio UNSPECIFIED UNSPECIFIED UNSPECIFIED Noga, Georg UNSPECIFIED UNSPECIFIED UNSPECIFIED Chen, Xinping UNSPECIFIED UNSPECIFIED UNSPECIFIED Bareth, Georg UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-450357
DOI:	10.3390/rs6010064
Journal or Publication Title:	Remote Sens.
Volume:	6
Number:	1
Page Range:	S. 64 - 87
Date:	2014
Publisher:	MDPI
Place of Publication:	BASEL
ISSN:	2072-4292
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Geosciences > Geographisches Institut
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SUPPORT VECTOR MACHINES; LASER-INDUCED FLUORESCENCE; NUTRIENT DEFICIENCIES; NITROGEN DEFICIENCY; VEGETATION INDEXES; BIOTIC STRESS; GREEN PLANTS; REFLECTANCE; PLS; REGRESSION Multiple languages Environmental Sciences; Geosciences, Multidisciplinary; Remote Sensing; Imaging Science & Photographic Technology Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/45035