A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains Chun-Hua Xiao2,Shao-Kun Li'2.,Ke-Ru Wang2,Yan-Li Lu2,Jun-Hua Bai2 Rui-Zhi Xie2,Shi-Ju Gao2,Qiong Wang",and Fang-Yong Wang' Key Labo ogy Agricu structio Crop/ Xinjiang. ence.Ch pees /N Chinese Academy es.Beijing 100081.P.R.China Tel:+86-010-68918891 lishkemail.caas.net.cn Abstract.The spectral signatures of crop canopies in the field provide much information relating morphological or quality characteristics of crops to their optical properties.This experiment was conducted using two winter-whea (Triticum aestivum)cultivars,Jingdong8(with erect leaves)and Zhongyou950 (with horizontal leaves). We analysiced the relation between the directior s and the laeves nitrogen c ontent(LNC).The result sho at th at the on th e upper canopy a d th ower laye r,the spe 60 the analys and the st leaf blade st with root mea and 0.6461 for Zhong ients of de measured and estimated grain p in contents were 0 7467 and 0 7590 Thus grain protein may be reliably predicted from the leaf layer spectral model. Keywords:wheat canopy,leaf distribution,direction spectra,view angle,model. 1 Introduction The spectral characteristics of a crop canopy are determined not only by biophysical and biochemical features and also plant structural attributes.Leaf optical properties are a main factor for canopy spectral. ·Corresponding author. D.Li,Y.Liu,and Y.Chen (Eds.):CCTA 2010.Part IV.IFIP AICT 347.pp.16-29.2011. IFIP International Federation for Information Processing 2011 D. Li, Y. Liu, and Y. Chen (Eds.): CCTA 2010, Part IV, IFIP AICT 347, pp. 16–29, 2011. © IFIP International Federation for Information Processing 2011 A Leaf Layer Spectral Model for Estimating Protein Content of Wheat Grains Chun-Hua Xiao1,2, Shao-Kun Li1,2,3,*, Ke-Ru Wang1,2, Yan-Li Lu2 , Jun-Hua Bai2 , Rui-Zhi Xie2 , Shi-Ju Gao2 , Qiong Wang2 , and Fang-Yong Wang1 1 Key Laboratory of Oasis Ecology Agriculture of Xinjiang Construction Crop/ Center of Crop High-Yield Research, Shihezi 832003, Xinjiang, China 2 Institute of Crop Science, Chinese Academy of Agricultural Sciences / National Key Facility for Crop Gene Resources and Genetic Improvement, NFCRI, Beijing 100081, China 3 Department of Crop Culture, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China Tel.: +86-010-68918891 lishk@mail.caas.net.cn Abstract. The spectral signatures of crop canopies in the field provide much information relating morphological or quality characteristics of crops to their optical properties. This experiment was conducted using two winter-wheat (Triticum aestivum) cultivars, Jingdong8 (with erect leaves) and Zhongyou9507 (with horizontal leaves). We analysiced the relation between the direction spectral characteristics and the laeves nitrogen content(LNC). The result showed that the spectral information observed at the 0° angle mainly provided information on the upper canopy and the lower layer had little impact on their spectra. However, the spectral information observed at 30° and 60° angles reflected the whole canopy information and the status of the lower layer of the canopy had great effects on their spectra. Variance analysis indicated that the ear layer of canopy and the topmost leaf blade made greater contributions to CDS. The predicted grain protein content (GPC) model by leaf layers spectra using 0° view angle was the best with root mean squares (RMSE) of 0.7500 for Jingdong8 and 0.6461 for Zhongyou9507. The coefficients of determination, R2 between measured and estimated grain protein contents were 0.7467 and 0.7599. Thus, grain protein may be reliably predicted from the leaf layer spectral model. Keywords: wheat canopy, leaf distribution, direction spectra, view angle, model. 1 Introduction The spectral characteristics of a crop canopy are determined not only by biophysical and biochemical features and also plant structural attributes. Leaf optical properties are a main factor for canopy spectral. * Corresponding author