Effect of seeding date on the tray raised seedling quality for rice transplanter in Boro season

Abstract

Mechanical rice transplanter needs a special type of seedling raised in-tray. Low temperature affected the quality of rice seedlings in Boro season. The purpose of this study was to find out the effect of seeding date on the properties of tray-type seedlings of three rice varieties namely BRRI dhan86, BRRI dhan89 and BRRI dhan92. This study was conducted in three locations namely Tangail, Rangpur and Gazipur in the Boro season of 2019-20. Four sowing date and three locations were considered and two factorial randomized completely block design (RCBD) with three replications was followed in the study. Characteristics of tray-raised rice seedlings suitable for mechanical transplanting in Boro season were revealed by this study. Seedling height and leaf number satisfied the requirement of transplanting. Seedling emergence was completed within 10 days after sowing (DAS). Seedling mortality of the tested three varieties started after 25 DAS in all locations. The seedling survival rate of BRRI dhan92, BRRI dhan89 and BRRI dhan86 exhibited the highest differently in a different location. The highest stem thickness of seedling was observed in all the tested varieties if seeds were sown on the 2nd and 3rd week of December in Gazipur and Rangpur location and 3rd and 4th week of December in Rangpur location. All the tested varieties showed a stem thickness of more than 1.5 mm. The highest stem strength was obtained if seeds were sown in the tray on the 3rd week of December. Variety showed inconsistent results on stem strength. The 2nd and 3rd week of December is an appropriate seeding time for optimum seedling height, stem strength and stem thickness in three locations. Seeding time affected the seedling emergence, mortality and height in the Boro season due to temperature variations and cold waves.