New High Quality and Early Maturing Rice Cultivar, “Wonchubyeo” Mutated from Chucheongbyeo

“Wonchubyeo” is a new japonica rice (Oryza sativa L.) cultivar developed by the Korea Atomic Energy Research Institute (KAERI) and was released in 2004. In order to select the mutants of Chucheongbyeo with good traits, the seeds were irradiated with 250 Gy gamma ray (83.3 rad/min) emitted from ⁶⁰Co in a radiation facility at the KAERI in 1992. Compared to the original cultivar, Chucheongbyeo, “Wonchubyeo” has an early heading date, around August 6, and a short culm length. And “Wonchubyeo” has slightly less tillers per hill, and a lower lodging degree and ripened grain ratio, but more spikelets per panicle than those of Chucheongbyeo. It has considerably erect pubescent leaf blades and a tough culm with good canopy architecture. It is moderately resistant to blast, but susceptible to major insect pests. “Wonchubyeo” has medium to small grains with clear non-glutinous endosperm rice without white center and white belly, and its palatability of cooked rice is excellent. The yield performance of “Wonchubyeo” was about 5.56 MT/ha, which was higher than that of Chucheongbyeo with 5.49 MT/ha, in the local regional trials at 3 sites (Pocheon, Pyongtaek and Nonsan) during 2000~2001. It could be recommended for the northern and central plain areas of Korea.