Determination of seedling age for rice transplanter

Rice transplanter is a labor saving technology. To find out suitable seedling age for rice transplanter two experiments were conducted in Bangladesh Rice Research Institute, Bangladesh in aman season (Sptember, 2012) and boro season (January, 2013). Seedlings were raising in plastic trays using sandy loam soil mixed with 25% well decomposed cow dung. We evaluated 8, 12, 16 and 20 day’s old seedling of BRRI dhan49 and BRRI dhan46 in aman and 15, 20, 25 and 30 day’s old seedling of BRRI dhan29 and BRRI dhan45 in boro season. BRRI dhan45 and BRRI dhan46 were bold; BRRI dhan29 and BRRI dhan49 were fine grain rice cultivar. Leaf number, shoot and root length, seedling vigor and strength increased with the advances of age in both years in all varieties. But bold type grain rice cultivar produced desirable leaf number and attained suitable height earlier than fine grain rice cultivars. The recommended seedling number (3 leaves per seedling) and suitable seedling height (12cm) could be achieved from 12 to 16 days old seedling in aman and 25 to 30 days old seedling in boro for transplanting using rice transplanter. Farmer’s could be saved 4 to 5 US$ per 33 decimal from seedling raising for transplanting by rice transplanter.