Prediction of grain protein based on canopy spectra in wheat with different plant types

Canopy spectra varied with plant type in winter wheat. So it is an important approach to improve the prediction of wheat protein according to plant type. The canopy spectral reflectance was measured using a ground-based spectroradiometer(ASD2500). It was analyzed that the vertical distribution of leaf chlorophyll content and the correlations between Difference Chlorophyll Content(DCC) and grain quality indices, spectral parameters. The results showed that gradients of leaf chlorophyll contents at different levels varied with plant type and growth stages. Varieties with planophile leaves presented higher DCC than varieties with erectophile leaves under the same conditions. The correlation DCC and grain quality indices, spectral parameters were improved when plant types were taken into considered. The correlative model of GPC and one of hyperspectral parameters can be constructed indirectly by DCC. The best stage for GPC prediction was at grain filling stage, and the best sensitive parameter is P_Depth560. Furthermore, the models that predicted GPC using P_Depth560 at grain filling stage were constructed and validated preliminarily for two types respectively.