Annual Variation of the Grain Shattering Degree in Main Rice Cultivars in Okayama Prefecture, Japan

Abstract

We investigated the annual variation of the grain shattering degree in rice by the grasping method using four rice cultivars cultivated in Okayama prefecture; “Hinohikari” with a hard shattering habit, “Omachi” with a slightly easy shattering habit, “Akebono” with an easy shattering habit, and “Asahi” with a very easy shattering habit. The field experiments were conducted in a high temperature year, 2010 and a low temperature year, 2015. The shedding rate estimated by the grasping method hardly varied with the year in “Hinohikari” and “Omachi”. However, it was higher in 2015 than in 2010 in “Akebono” and “Asahi”, and the annual variation was larger in “Asahi” than in “Akebono”. These results suggest that the shedding rate fluctuates with the year largely in cultivars with an easier shattering habit and that it is increased by a low temperature.