Retrieval of biophysical parameters and assessment of Alternania disease severity in safflower using ground ground based hyper spectral radiometry.

Abstract

This study demonstrated the utility of ground based hyperspectral remote sensing for assessing certain biotic and abiotic traits associated with safflower. Experiment was conducted with 8 cultivars grown under three depths. Results showed that Normalised Pigment to Chlorophyll Index (NPCI) had highest correlation (r= 0.78) with the measured chlorophyll. Regressing the NPCI upon measured chlorophyll resulted in a linear functional relationship (Rl = 0.6086, p < 0.001), which when validated with independent data set showed promising results. NDVI and LAI measured during flower initiation stage showed strong relation with dry matter, biomass and seed yield. Mean reflectance spectra between healthy and Alternaria diseased plants showed a distinct separation of bands in visible, NIR and SWIR regions. Among several hyperspectral indices tested, Red edge Normalised Difference Vegetation Index, Normalised Pigment Chlorophyll Index and Normalised Difference Vegetation Index were found superior for detection of Alternaria disease at early stages of infestation.