Sterility of Japanese Rice Variety “Shinrei” Grown under Short-day Conditions

Abstract

The Japanese rice variety “Shinrei” from the Kyushu region was subjected to short-day (9-h daylength) and long-day (14-h daylength) treatment in a phytotron with a day/night temperature regime of 30/22°C. Under the long-day and short-day conditions, the heading time was 85 days and 60 days, respectively; and, the percentage of sterility was 3% and 28%, respectively. Under the short-day condition, the anther was bent and was about 1.2 mm in length, while under the long-day condition the anther was about 1.7 mm in length. An increase in sterility was observed when the anther was shorter than about 1.5 mm and the number of pollen grains per anther was less than about 600. The anther length was affected by day-length from 3 to 9 days after panicle initiation as well as by days to panicle initiation. Short-day treatment during this period decreased the panicle length and number of pollen grains per anther, resulting in an increase in the percentage of sterility.