Effect of Low Light Stress on Plant Height, Tiller Number, Panicle Number, Leaf Area and Yield of Long Duration Rice (Oryza sativa. L) Varieties

The purpose of this study was to determine the impact of low light stress on the morphological parameters and yield of long duration rice genotypes. The experiment was carried out in the field of National Rice Research Institute, and the field layout was done as per the split plot design, with the light in the main plot and the varieties in the sub-plot. During Kharif 2019, the experiment was carried out at plot-4, V-block under the Department of Crop Physiology and Biochemistry at the National Rice Research Institute (NRRI), Cuttack. The experiment was carried out with three different light intensities, namely 100% light as treatment-I (Control), 75% light as treatment-II, and 50% light as treatment-III. Eleven long duration rice varieties were chosen based on yield to investigate the effect of low light on their morphology and yield. It was observed that at 50% flowering stage in 75% and 50% light intensities, plant height and leaf area increases but tiller number, panicle number and yield reduces. At 50% light intensity, yield reduction was significantly greater than 75% light intensity. Among the varieties Nasati Sali, Nalini Sali and Swarnaprabha was recorded highest grain yield in 100% (5.10 t ha-1), 75% (4.27 t ha-1) and 50% light intensity (3.05 t ha-1) respectively.