Nursery Management for Improving Seedling Length and Early Growth after Transplanting in a Semi-Dwarf Rice Cultivar Hokuriku 193

Nursery management methods for elongating seedlings are needed for stabilization of early growth after transplanting in the semi-dwarf rice cultivar Hokuriku 193, unlike japonica commercial cultivars. This study aimed to investigate how keeping the plants at 28 degrees C for 5 d after sowing (H treatment) and nitrogen top-dressing (N treatment) affects seedling quality and early growth after transplanting. Control plants had seedling lengths of 6.5 cm to 10.9 cm at transplanting. The H and N treatments significantly increased the seedling length, and the increase was greater in the H-treated plants. The H x N treatment elongated seedlings by 2.5 - 3.7 cm compared to the control plants. The N treatments, but not the H treatments, improved biomass production and filleting early after transplanting owing to the high nitrogen concentration in the seedlings. Combining H and N treatments can contribute for improving seedling length and early plant growth after transplanting in Hokuriku 193.