Optimizing transplanting age for enhanced yield and seed quality of T. Aman rice varieties in Subtropical Bangladesh: A study on varietal responses

A field experiment was conducted during the Aman season (July - December), in a subtropical region of Bangladesh, to address the prevailing challenge of low national T. Aman rice yield and the common farmer practice of using over-aged seedlings. The study aimed to determine the optimal seedling age and genotype combination for maximizing both grain yield and seed quality. Three rice varieties (BRRI Dhan32, BRRI Dhan62, and BRRI Dhan80) were evaluated across four transplanting ages (20, 25, 30, and 35 days), using a two-factor Randomized Complete Block Design (RCBD). Results demonstrated that the variety BRRI Dhan32 was statistically superior, yielding the highest grain (4.68 t.ha-1), and exhibiting the best seed germination (88.33%), primarily due to its robust yield components, including a greater number of effective tillers and filled seeds per panicle. Seedlings transplanted at 30 days old (A3) significantly outperformed other ages, promoting optimal growth and development and resulting in a maximum yield of 4.83 t.ha-1 and germination of 92.01%. Crucially, the interaction between BRRI Dhan32 and 30-day-old seedlings (V1A3) produced the highest combined performance, recording an exceptional grain yield of 5.12 t.ha-1, superior germination (92.86%), and the highest vigor index (2152.49), largely attributable to enhanced 1000-seed weight. This research conclusively recommends cultivating BRRI Dhan32 with 30-day-old seedlings as a practical and effective strategy to significantly boost the productivity and quality of T. Aman rice, thereby enhancing national food security in subtropical environments.