Abstract: Taking hybrid millet（Setaria italica） Zhangza No.10 as experiment material, the leaf length（maximum length）, leaf width（maximum width）, leaf biomass, stem node length（maximum length）, stem node biomass, spike length and spike biomass of different leaf position of Zhangza millet were dynamically measured through field cultivation experiment. The allometric relationship between the biomass of different organs and their geometric morphological structure characteristic parameters were analyzed, and the geometric morphological structure model of millet organs based on biomass was constructed. The results showed that the allometric relationship between leaf biomass and leaf length, stem node biomass and stem node length, and spike biomass and spike length was expressed by the power exponential equation, and the determination coefficients of the equations were 0.83, 0.77 and 0.98, respectively. The leaf biomass and leaf width showed a quadratic curve, and the determination coefficient was 0.80. The significant test results of equations all showed extremely significant level （P<0.01）. The root mean square errors between the measured and simulated values of leaf length,and leaf width were 5.28 cm and 0.35 cm, respectively. The root mean square error between the measured and simulated values of stem node length was 1.17 cm. The root mean square error between the measured and simulated values of spike length was 2.40 cm. There was a significant statistical correlation between the geometric structure parameters of different organs in millet and their corresponding cumulative biomass, and the prediction of the geometric structure model of millet organs based on biomass had high accuracy.

Key words: millet（Setaria italica）, biomass, allometric relationship, geometric morphological structure, characteristic parameter