Effect of different chemical priming agents on physiological and morphological characteristics of rice (Oryza sativa L.)

The research was conducted following a Completely Randomized Design (CRD) to investigate the effects of seed priming using various chemical treatments on the germination and growth parameters of two rice cultivars, BRRI Dhan-66 and IR 80991-B-330-U-1. Ten different priming agents, including H(3)BO(3), CaCO(3), CuSO(4), DAP, FeCl(2), MoP, PEG (5 %), PEG (10 %), Urea, and ZnSO(4), were applied to treat the seeds, each treatment being replicated three times. A control group underwent hydro-priming. The seeds were soaked in the treatments for 24 h. After the priming treatments, the seeds were subjected to a redrying process at a temperature of 26 ± 2 °C until they regained their original weight before being transplanted onto blotting paper. Germination parameters such as germination percentage, germination speed, germination energy, and vigor index were recorded for seven consecutive days. Growth parameters including root length, shoot length, fresh seedling weight, and dry seedling weight were measured at 10, 20, and 30 days after sowing. The results indicate significant variations among the treatments for germination parameters (p ≤ 0.001). Similarly, significant variations were observed in growth parameters, including shoot length, fresh weight, and dry weight (p ≤ 0.001). Among the rice varieties, BRRI Dhan-66 exhibited better results for germination percentage (81.58 %), germination speed (62.78 %), germination energy (52.06 %), vigor index (1312), fresh weight (0.807g), and dry weight of seedlings (0.053g). In contrast, the FeCl(2) treatment showed the best results, inducing respective increases of 25.19 %, 93.35 %, 94.95 %, and 29.07 % for germination percentage, speed, energy, and vigor index compared to the control, respectively. For growth parameters, the DAP and CuSO(4) treatments demonstrated better results. Our findings highlight that improved germination of primed rice seedlings is associated with germination energy, speed, vigor index, and the fresh weight of the seedlings. Furthermore, Pearson's correlation coefficient revealed there is significant positive correlation between germination percentage, speed, energy and vigor index but the strongest correlation exists between germination speed and germination energy (R = 0.94***) followed by germination percentage and vigor index (R = 0.92***). Based on our findings, we propose that seed priming significantly enhances rice seedlings' germination and growth parameters. BRRI Dhan-66, along with seed treatment using FeCl(2), can be effectively employed to achieve improved germination and growth in rice cultivation.