Varietal Differences on Growth Characteristics of Direct-sown Rice under No-tillage Paddy Field

In order to establish a labour-saved and environment friendly paddy rice system in southern Korea, no-tillage paddy system was proposed and investigated from 1992 to 1993. Basically this system includes a complete return of crop residules into the soil, and zero-tillage. In an effort to minimize labour requirement in rice farming, several cultivars were directly sown and grown under the system and the characteristics of the growth and yield potential of the cultivars were compared with those grown in an ordinary paddy soil. Joryeongbyeo, Dongjinbyeo, Daeyabyeo and Calose rices showed high level of seedling establishment in the no-tillage padddy system. However, the value was significantly lower than in those of the cultivars direct-sown in an ordinary tillage paddy condition. The rice direct-sown and grown under the no-tillage paddy system showed significantly decreased number of tillers per square meter and plant height, but increased ripened grains. The lodging-related characteristics of rice plant, such as band breaking weight, the length of top 3rd ∼4th internodes, the height of weight center, and lodging index, were observed positive aspects in cultivars such as Hwasungbyeo, Hwayongbyeo, Joryeongbyeo, Calose and Calose 76 and being considered adaptable to direct-sown under the no-tillage paddy system.