Grain Detachment Strengths and Grain Mass of Three Rice Types

Abstract

Experiments were carried out to find out the characteristics of grain detachment strength due to straight pull (Ss), grain detachment strength due to perpendicular pull (Sp) and grain mass of three rice types. Rice varieties used in the experiment were Arborio (Javanica type), Bluebonnet 50, Jhona 349 (Indica type), and Koshihikari (Japonica type). The samples were cultivated conventionally, and harvested by hand. Panicle construction models featuring the grain position order in the panicle were made to determine the distributions of Ss, Sp and grain mass in the panicle. The distribution of Ss of all tested varieties was smaller toward the outer part of the panicle. The same tendecy was detected to the Sp, except Bluebonnet 50, in which the distribution was almost uniform. Grain mass of Arborio and Koshihikari was distributed uniformly. On the other hand, the distributions of Bluebonnet 50 and Jhona 349 were slightly bigger toward the upper port of the panicle. By using probability ellipse analysis, the characteristics of grain detachment strength were proposed by both Ss and Sp. By using discriminat analysis, it was found that rice was better grouped based on the ricevariety than by the rice type. Among the tested verieties, Koshihikari was the strongest followed by Arborio and Bluebonnet 50 which were almost the same, Jhona 349 was the weakest.