Differences of Grain Amylose Contents at Different Positions within a Panicle Between the Compact-and Loose-Panicle Rice Varieties

The variation of amylose content(AC)among grains at different positions within a rice panicle was investigated with compact and loose panicle types of japonica rice varieties Zhejing 22 and Zhejing 27 as materials.The differences between the maximum and minimum of grain AC in Zhejing 22 and Zhejing 27 reached 13.53 and 10.30 percent point,respectively.The variation range of AC in compact panicle is larger than that in loose panicle.The AC for each grain in a panicle followed a normal distribution.The correlation coefficients between grain AC and its position in the primary and secondary branches of the panicle in compact and loose panicle types were-0.1167 and-0.3140,respectively,showing that the coefficient of relationship in the loose panicle type was more significant than that in the compact type,and in addition,the coefficient of relationship between AC and grain position in the primary branch was higher than that in the secondary one.The AC of the grains from the top of branch was higher than that of the second grain under the first top one.The distribution of grain AC in a panicle was similar between the loose panicle type and the compact panicle type.It was better to choose the third or forth grains in the panicle branch for AC analysis if whole or half a grain sample should be determined.