A Preliminary Study On Hyperspectral Reflectance Phenotype Of Rice Genotype Of Different Phosphorus Efficiency

Quantitative phenotype description is becoming increasingly important in the recent post-genome research. This study aimed to pioneerly investigate the difference in leaf hyperspectral reflectance signatures among genotypes of different P efficiency and discriminate the genotypes with spectral data. A hydroponic culture experiment consisting of four rice genotypes (2 wild genotypes and 2 mutants) of different P efficiency and three P levels was conducted from October 8 through December 20 in 2015 in a glasshouse at the Experimental Farm, Zhejiang University, Hangzhou, China. Tiller number, plant height, root length and leaf chlorophyll content were determined at tillering and booting. Reflectance (350-2500nm) of both the upper surface and the lower surface in the flag leaf and the second lowest leaf were measured with a spectrometer. Decreased tiller number, increased root length and decreased plant height were observed at the P-deficient level for all the genotypes, but the effect extend of P deficiencies on the phenotypic parameters varied with the genotypes. It was found that the genotypes had a significant (P=0.05) influence on most of the selected vegetation indices and the VIs could be used to discriminate the genotypes. The VIs tended to keep unchanged with the P level in the wildtype ’Ribenqing’, but remarkably changed in a similar pattern in the two mutants.We also found a significant difference between the leaf upper surface reflectance and the lower surface reflectance in the spectral region of 800-1100nm and 1400-2500nm, and the lower surface reflectance was greater than the upper surface reflectance. The difference values between the two surfaces at the selected wavelength were significantly affected by the genotypes at both tillering and booting, and these spectral parameters could also be used to sensitively discriminate the genotypes.