Vertical features of yellow rust infestation on winter wheat using hyperspectral imaging measurements

Yellow (stripe) rust Puccinia striiformis has caused severe losses on wheat in yield and grain quality in China. As the largest land area devoted to wheat production, China has also the largest area prone to yellow rust epidemics. Traditionally, the disease assessment was visually investigated in the field by experienced farmers or pathologists. The emergency of hyperspectral measurements has distinct advantages over conventional visual inspection, and they can collect the information repeatedly and automatically. In comparison with the hyperspectral measurements using a non-imaging spectrometer, the spectral and imaging features of pure yellow rust spores can be simultaneously collected. The study on monitoring the vertical features of yellow rust infestation on winter wheat was performed using ground-based imaging spectrometer. The results show that the infection severities generally show a gradual increasing trend from F-1 (F=Flag leaf) to F-3, while the relative chlorophyll shows an inverse change. The spectral reflectance gradually increases from F-1 to F-3 in the visible spectral region, while it is the very reverse in the near-infrared (NIR) region.