Effects of Manganese on Yield and Yield Attributing Parameters of Rice (Oryza sativa L.)

Background: Manganese (Mn) being one of the micronutrients available in acid soils acts crucial role in crop plants. In Assam soil, its concentration is 3-52 ppm whereas in plants the critical limit is 2-3ppm. Although the effects Mn on plants have been well documented, information on its impacts on yield and yield components in upland rice crop grown in Assam was scanty, and deserved its investigation. Method: A pot experiment was carried out to study the effects of Mn (0, 10,20,30 ppm Mn as MnSO4H2O) foliar spray (each 1000cm3) at vegetative stage i.e.70days after sowing, on yield and yield components of ten rice genotypes (Kanaklata, Mulagabharu, Kapilee, Disang, Kolong, Joymoti, Jyoti Prasad, Luit, Lachit and Chilarai) cultivated in Assam. Conclusion: The lower dose of Mn (10ppm) significantly increased panicle length (16.29-37.46%), panicle weight (10.54-19.50%), panicle number per plant (4.54-13.63%), number of seeds per panicle (18.38-36.48%), test weight (7.21-29.15%), high density grains (5.59-30.45%), economic yield (14.40-28.03%), biological yield (32.58-47.70%), and harvest index (3.2-7.90%). 30ppm Mn affected adversely all the physiological attributes in the study. Among the ten genotypes, Kanaklata performed the best followed by Chilarai in the experiment.