A potential retardant for lodging resistance in direct seeded rice (Oryza sativa L.)

Sinniah, U. R., Wahyuni, S., Syahputra, B. S. A. and Gantait, S. 2012. A potential retardant for lodging resistance in direct seeded rice ( Oryza sativa L.). Can. J. Plant Sci. 92: 13–18. Yield losses in rice are heavy, particularly when lodging occurs after heading. A major contributing factor towards lodging is the tall phenotypic characteristic of the plant. In rice, application of growth retardant can reduce plant height by means of internode retardation. In this study, paclobutrazol at 50, 100 and 200 ppm was applied as a foliar application at panicle initiation on MR 219 and MR 84 cultivars and its effects on growth, lodging resistance and yield were studied. Foliar-applied growth retardant inhibited plant growth and retarded internode and culm length but increased culm diameter. All treated plants had higher bending resistance compared with the control. A significant positive correlation was observed between increased culm diameter and stem bending resistance (r=0.885). Histological studies showed greater compaction of parenchyma cells with thickening of parenchyma cell walls. Treatments with either 50 or 100 ppm paclobutrazol gave significant retardation of internodes and gave higher stem bending resistance with significant increase in yield.