title: Detecting Sugarcane yellow leaf virus infection in asymptomatic leaves with hyperspectral remote sensing and associated leaf pigment changes.
abstract: Sugarcane infected with Sugarcane yellow leaf virus (SCYLV) rarely produces visual symptoms until late in the growing season. High-resolution, hyperspectral reflectance data from SCYLV-infected and non-infected leaves of two cultivars, LCP 85-384 and Ho 95-988, were measured and analyzed on 13 July, 12 October, and 4 November 2005. All plants were asymptomatic. Infection was determined by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Results from discriminant analysis showed that leaf reflectance was effective at predicting SCYLV infection in 73% of the cases in both cultivars using resubstitution and 63% and 62% in LCP 85-384 and Ho 95-988, respectively, using cross-validation. Predictive equations were improved when data from sampling dates were analyzed individually. SCYLV infection influenced the concentration of several leaf pigments including violaxanthin, beta-carotene, neoxanthin, and chlorophyll a. Pigment data were effective at predicting SCYLV infection in 80% of the samples in the combined data set using the derived discriminant function with resubstitution, and 71% with cross-validation. Although further research is needed to improve the accuracy of the predictive equations, the results of this study demonstrate the potential application of hyperspectral remote sensing as a rapid, field-based method of identifying SCYLV-infected sugarcane plants prior to symptom expression.
authors.affiliation: USDA-ARS, Sugarcane Research Laboratory, 5883 USDA Rd., Houma, LA 70360, United States. michael.grisham@ars.usda.gov
authors.forename: Michael P
authors.initials: MP
authors.lastname: Grisham
authors.forename: Richard M
authors.initials: RM
authors.lastname: Johnson
authors.forename: Paul V
authors.initials: PV
authors.lastname: Zimba
mesh_terms: D052679:Luteoviridae / Q000302:isolation & purification*; D010860:Pigments, Biological / Q000032:analysis; D010935:Plant Diseases / Q000821:virology*; D018515:Plant Leaves / Q000737:chemistry / Q000821:virology*; D031786:Saccharum / Q000737:chemistry / Q000821:virology*; D013057:Spectrum Analysis / Q000379:methods*; D014773:Virology / Q000379:methods*
chemical_list: D010860:Pigments, Biological