STANDARDIZATION OF WATER TEMPERATURE AND TIME IN CONTROLLING MAJOR SEED BORNE PATHOGENS OF RICE, WHEAT AND MAIZE

Abstract

An investigation was conducted on hot water seed treatment of rice, wheat and maize seeds in controlling seed infection for proper germination during the period from July 2021 to December 2022, at the central laboratory of the Department of Plant Pathology, Sher-e-Bangla Agricultural University, Dhaka-1207.Suitable temperature and time for seed treatment were determined. Irrespective to the cereal seeds, the temperature and time of treatment had shown significant effect on reduction of seed infection and increase of seed germination. The hot water treatment also had remarkable effect on rotten seeds, dead seeds and abnormal seedlings. The experimental treatments were T 1 = Hot water at 52℃ for 5 and 10 min, T 2 = Hot water at 54℃ for 5 and 10 min, T 3 = Hot water at 56°C for 5 and 10 min, T 4 = Hot water at 58℃ for 5 and 10 min, T 5 = Hot water at 60℃ for 5 and 10 min and T 6 = Control (Using normal water at ambient temperature (25±1°C)). Data were collected on % seed germination, % seed infection, % rotten seed and % dead seed. The experiments were conducted following Completely Randomized Design (CRD) with 4 replications. In case of rice seed, the highest seed germination (91%) and the lowest seed infection (0%) were noted at 56°C for 5 min while (94%) seed germination and (0%) seed infection were recorded at 54°C for 10 min. In case of wheat seed, the highest seed germination (88%) and the lowest seed infection (0%) were recorded at 54°C for 5 min while it was (90%) seed germination and (0%) seed infection at 52°C for 10 min. In case of maize seed, the highest seed germination and the lowest seed infection respectively were (82%) and (0%) at 58°C for 5 min while it was (84%) seed germination and (0%) seed infection at 56°C temperature for 10 min. In case of rice, Fusarium spp and in case of wheat & maize, Bipolaris spp was found. Irrespective to the cereal seeds, the seed infection was found to be reduced with the increase of temperature and time. The percent dead seed also increased with the increase of temperature. Thus, the rice seed should be treated with hot water at 56°C for 5 min or 54°C temperature for 10 min. In case of wheat seed, farmers are suggested to treat with hot water at 54°C for 5 min or 52°C temperature for 10 min while for maize seed, farmers are recommended to go through hot water at 60°C temperature for 5 min or 56°C temperature for 10 min for getting the highest seed germination minimising the seed infection.