Abstract
Dry weight, concentration and the amount of phosphorus, potassium, magnesium, calcium, and zinc in each brown rice grain (Oryza sativa L. japonica) from different grain positions on the panicle were analyzed. From each of “Nipponbare”, “Koshihikari” and “Snow peal”, 308-368 grains/3 panicles were collected, and each item was investigated in relation to the grain position on the panicle. The results were analyzed by non-parametric tests using each panicle, because the values for a single grain did not show normal distribution and showed significant difference among panicles in each variety (P<0.05). When the grains on the panicle were divided into nine groups depending on the position of the primary and secondary rachis branches, almost all of the analytical values varied with the grain position significantly (P<0.05). Dry weight, and total amounts of phosphorus, potassium and magnesium in the rice grains on the secondary rachis branches were lower than those on the primary rachis branches. On the other hand, phosphorus, potassium, magnesium and zinc concentrations were higher in the rice grains at the second and third positions from the top of the secondary rachis branches, which flowered later, than at other positions. Rice grains on the rachis branches at the basal position of the panicle, which flowered later, had lighter dry weight and higher phosphorus, potassium, magnesium and zinc concentrations than those at the apical position of a panicle. When the primary rachis branches (including secondary rachis branches) were classified into 8-13 positions from the apex to the base, the lower the branch position, the lighter the dry weight and the higher the mineral concentration of the grains, with a significant difference (P<0.05) in most items.
