International Journal of Agriculture Sciences ISSN: 0975-3710&E-ISSN: 0975-9107, Volume 11, Issue 12, 2019 || Bioinfo Publications || 8640 Research Article EFFECT OF HIGH-DENSITY PLANTING ON LIGHT INTERCEPTION, GROWTH AND YIELD OF RICE (Oryza Sativa L.) UNDER MODIFIED SYSTEM OF RICE INTENSIFICATION MOHAN KUMAR S. 1 , THAVAPRAKAASH N. 2* , PANEERSELVAM S. 3 , JAGADEESWARAN R. 4 AND SRITHARAN N. 5 1 Agro Climate Research Centre, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India 2 Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India 3 Director, Water Technology Centre, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India 4 Agricultural College and Research Institute, Kudumiyanmalai, 622104, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India 5 Department of Crop Physiology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India *Corresponding Author: Email - thavaprakaash.n@tnau.ac.in Received: June 06, 2019; Revised: June 26, 2019; Accepted: June 27, 2019; Published: June 30, 2019 Citation: Mohan Kumar S., et al., (2019) Effect of High Density Planting On Light Interception, Growth and Yield of Rice ( Oryza sativa L.) under Modified System of Rice Intensification. International Journal of Agriculture Sciences, ISSN: 0975-3710 & E-ISSN: 0975-9107, Volume 11, Issue 12, pp.- 8640-8642. Copyright: Copyright©2019 Mohan Kumar S., et al., This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. Academic Editor / Reviewer: Introduction Rice (Oryza sativa L.) is the world’s important staple food crop and plays a vital role in food security. It accounts for 25 percent of total cereal grain production next to wheat. By the year 2025, the targeted demand of rice for Indian population is 130 mt. Much of the demand will be arising from Asia, which is the home of two- third of the world’s population and where 90 percent of total rice supply is grown in diverse environments. The productivity of rice per unit area is much lower to satisfy the food to increasing population and food security [1]. Plant density plays a significant role in increasing yields, as it influences the tiller formation, solar radiation interception, nutrient uptake and leaf gas exchange parameters, which ultimately affect its growth and development [2]. Improper plant spacing reduced yield of rice up to 20-30 percent while optimum spacing ensures better plant growth through efficient utilization of solar radiation and nutrients [3]. For attaining higher productivity, proper light interception by each segment of the canopy is important. In rice, the number of panicle per hill also a determinant factor in maximizing the yield. High density planting helps in maintain panicle number and optimum yield level. The rice yield increases as the density of planting increases to some extent and then starts declining [4]. System of rice intensification (SRI) is the method of rice cultivation enhanced the yield of rice by following various principles. However, lower planting density in SRI affected the growth and yield of rice compared to conventional method [5]. Due to poor establishment and vigour, the number of productive tillers may get reduced and in turn grain yield of rice. Hence, modified SRI is one in which modification in certain principles of SRI using scientific knowledge of management practices to adapt to local climatic condition in view of increasing yield and farmers income [6]. In keeping the above principles, the high density planting in rice with some modified SRI principles, the present study was conducted to examine the effect on light interception, growth, and yield of rice. Material and Methods The field trial was conducted at Wetland farm of the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore in late Samba (September to January) season of during 2018-19. The experimental site belongs to Western agro-climatic zone of Tamil Nadu with an elevation of 426.7 m above mean sea level (MSL) and located geographically at 11°83' N latitude, 76°71' E longitude. The soil of the experimental field was clay loam in texture with the nutrient status of the field during start of the experiment was low in nitrogen, medium in phosphorous and high in potassium. The field experiment was designed with randomized complete block design with three replications. The treatments comprised of eight plant spacing levels viz., T1 - 25 × 25cm + 100% RDF (Recommended dosage of fertilizer) (SRI), T2 - 25 × 20cm + 100% RDF, T3 - 25 × 15cm + 100% RDF, T4 - 25 × 15cm + 125% RDF, T5 - 20 × 20cm + 100% RDF, T6 - 20 × 15cm + 100% RDF, T7 - 20 × 15cm + 125% RDF) follows System of rice intensification (SRI) principles and T8 - Conventional cultivation. Latest released variety Rice CO-52 was used in this field experiment. Recommended dose of fertilizers (150: 50: 50 kg N: P2O5: K2O/ha) are applied as urea, single super phosphate and muriate of potash to all the plots as per the treatment. Nitrogen and potassium were given in four equal split doses at basal, active tillering (50 DAT), panicle initiation (70 DAT) and flowering stages (100 DAT). Full dosage of phosphorus, 25 percent of nitrogen and potassium were applied as basal prior to transplanting. International Journal of Agriculture Sciences ISSN: 0975-3710 & E-ISSN: 0975-9107, Volume 11, Issue 12, 2019, pp.-8640-8642. Available online at https://www.bioinfopublication.org/jouarchive.php?opt=&jouid=BPJ0000217 Abstract: Field investigation was conducted during the late Samba (September-January) season of 2018-19 at Wetland farms, TNAU, Coimbatore to study the effect of high density planting on light interception, growth and yield of rice (Oryza sativa L.) under modified system of rice intensification. The treatments comprised of T1 - 25 × 25cm with 100% Recommended Dose of Fertilizer (RDF) (SRI), T2 - 25 × 20cm with 100% RDF, T3 - 25 × 15cm with 100% RDF, T4 - 25 × 15cm with 125% RDF, T5 - 20 × 20cm with 100% RDF, T6 - 20 × 15cm with 100% RDF, T7 - 20 × 15cm with 125% RDF and T8 - Conventional cultivation with 100% RDF. The experiment was arranged in Randomised Complete Block Design with three replications. The result revealed that plant height was significantly higher in T4 and was statistically similar with all other treatment except T8 in all the stages, but not at maturity stage. The LAI was significantly higher in conventional method of planting compared to all other treatments. Higher light interception were recorded with T5 over others but was statistically comparable with T6, T7 and T8, respectively. Grain yield was higher with T5, T4, T2 and T3 compared to other treatments. Keywords: Rice, High Density Planting, Light Interception, Modified System of Rice Intensification, LAI, Grain Yield