DISEASE INDEX OF BLAST OF RICE AND ITS IMPACT ON SEED TRANSMISSION

S Begum, MM Rahman, R Hasan, A Muqit, MM Islam, IJ Ema and M Asad-ud-Doullah1*
Journal of the Sylhet Agricultural University, Volume 9, Issue 2, 2022, Pages 177-187

Abstract:

Seed—borne infections of rice by Pyricularia oryzae (Teliomorph: Magnaparthe oryzae) were studied during two Boro scasons (2018/19 and 2019/20) with naturally infected seeds of three rice cultivars — namely, BRRI dhan28, BRRI dhan29 and Binadhan—10 in BADC farm of Sylhet of Bangladesh. The objectives of the study were to observe blast disease development in the field, determine seed infection, the subsequent impact of seed transmission, and on planting value of seeds. In this study, the disease index was the highest in the tillering stage of BRRI dhan28 followed by BRRI dhan29, and the lowest was in Binadhan—10 in both years. The moisture content of before-sowing seed samples of three rice varieties ranged from 12.10-13.00%, but samples of harvested seeds were 13.20—-14.50% in the boro season of the years. The purity percentages of before-sowing and after-harvest seeds of Binadhan—10 were the highest in both seasons (91.4, 94.4 and 93.3, 95.90) followed by BRRI dhan29 and BRRI dhan28. Highest normal seedlings were observed in Binadhan—10 in both seasons. Nine sced—borne fungi were recorded in after—harvest seed samples in 2018/19 and eight fungi in 2019/20, but no Pyricularia oryza was identified in tested seed samples. Binadhan—10 showed lower seed infection compared to other varieties. The seedling infection by blast pathogen at the coleoptile indicates seed—to—seedling transmission of the pathogen. The lowest coleoptile infection was observed in Binadhan—10 compared to BRRI dhan29 and BRRI dhan28. In both seasons, the highest planting value (46.33 & 71.56%) was reduced in Binadhan—10 followed by BRRI dhan28 (32.48 & 56.20%) and BRRI dhan29 (38.35 & 58.88%) before sowing seed samples. Binadhan—10 also exhibited the highest planting value (73.89 & 86.50%) in after harvest seed sample. Considering the data recorded from the field and laboratory Binadhan—10 was found to be better for cultivation in the Boro season in Sylhet.

Keywords:

Blast of rice, transmission, planting value, disease index, colcoptiles


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S Begum, MM Rahman, R Hasan, A Muqit, MM Islam, IJ Ema and M Asad-ud-Doullah1*. 2022. DISEASE INDEX OF BLAST OF RICE AND ITS IMPACT ON SEED TRANSMISSION, Journal of the Sylhet Agricultural University 9(2): 177-187.