Analysis of relationship between head rice yield and breaking force of Japonica rice grains at different maturity stages

Rice is the most important crop in China and half of the food demand of China is made up of rice products. The rice planting area is 29.694 mln ha and the annual yield of rice was 200 mln t in 2019. Head rice yield (HRY) is among the most important indices for rice production, but there was also an optimal HRY during the rice maturity process. Rice caryopsis was filled with starch and protein matter, and the physical properties changed with the degree of maturity, however the degree of maturity and the physical properties of the rice grains at different maturity stages affected the HRY. The optimal rice harvest time with maximum HRY is only be determined using the rice moisture content (MC) at present, the rice MC is the result of the cultivation, environmental, and meteorological conditions, but it does not represent the real physical properties of rice grains, this is obviously unsatisfactory, instead HRY should be closely related to physical properties such as breaking force. On the other hand, structural differences exist between the dorsal side and ventral side, such as the size and shape of the starch granules (Xiong et al., 2005), the tissues on the ventral side were softer than those on the dorsal side and a higher number of airspaces and less starch were present © 2022 Institute of Agrophysics, Polish Academy of Sciences