REGENERATION CAPACITY OF INBRED AND HYBRID RICE INFLUENCED BY PLANT GROWTH REGULATORS AND CUTTING MANAGEMENT

Abstract

An experiment was carried out at the Agronomy Field, Sher-e-Bangla Agricultural University, Dhaka during the period from November 2021 to July 2022 with a view to study the effects of variety of main crop and N dose (applied after the harvesting of main crops) on the performance of ratoon crop of boro rice. The experiment was carried out in a Split Plot Design, where three factors were selected as variety, plant growth regulators and cutting managements. The plot size was 3 square meters (1 m ×0.5 m). The plots were replicated three times and thus the total number of plots was 36 per split with 2 splits containing different boro rice variety. V 1 = BRRI hybrid dhan 5 (hybrid), V 2

= BRRI Dhan 47 (Inbred); C 0 : Cutting at ground level, C 1 : 10 cm above ground (second node), C 2 : 15 cm above ground (third node); G 0 : Control, G 1 : 100 ppm auxin, G 2 : 100 ppm gibberellin, G 3 : 100 ppm auxin+100 ppm gibberellin were selected treatments. For main crop the highest grain yield (7.53 t/ha.) was observed from the variety BRRI hybrid dhan 5. The lowest grain yield (6.53 t/ha.) was found from the variety BRRI Dhan 47. In ratoon crop the highest grain yield (0.79 t/ha.) was observed from the variety BRRI hybrid dhan 5 which is 10.53% of the main crop. The lowest grain yield (0.41 t/ha.) was found from the variety BRRI Dhan 47 which is 6.31% of the main crop. The interaction of variety and cutting height of main crop and application of PGRs had significant effect on any of the crop characters of ratoon crop. The interaction of variety and cutting height of main crop had highly significant effect on final grain yield of ratoon crop along with other yield contributing factors and found the highest grain yield (0.75 t/ha.) observed from the treatment combination of V 1 C 1 G 3 : BRRI hybrid dhan 5; 10 cm above ground (second node) and 100 ppm auxin+100 ppm gibberellin and the lowest grain yield (0.35 t/ha.) was found from the treatment combination of V 1 C 0 G 0 : BRRI Dhan 47; Cutting at ground level and Control. Yield of ratoon crop for BRRI hybrid dhan 5 was found 10.53% of the main crop and 10 cm above ground (second node) and 100 ppm auxin+100 ppm gibberellin combination can be considered for commercial ratoon crop cultivation.