INTRODUCTION Rice is the most important cereal crop and around 3 billion people, half of the world’s population, depend on rice for survival (Khush, 2004). More than 90% of the rice in the world is grown in Asia (FAO, 2009) which accounts for 35- 75% of total calorie intake (Khush, 2004). Rice ranks as second after wheat among the most staple food grain crops in Pakistan. The geographical area of Pakistan is 79.61 million hectares and its total cropped area is 22.51 million hectares (Govt. of Pakistan, 2005). Rice sowing area is estimated as 2.79 million hectares with production of 6.80 million tons during the year 2012-13 in Pakistan. Rice accounts 3.1% of the value added in agriculture and 0.7% of the GDP (Govt. of Pakistan, 2014). The total quantity of rice (rice milled equivalent) exported was 3.41 million tons and the export value was 2.06 billion US dollars during the year 2011 (FAO, 2013). Rice is an excellent food source as it has been found easy in digestion and has high nutritional contents. The energy needs obtained from rice accounts 80% for more than 2 billion peoples in Asia as it contains 80% starchy carbohydrate, 7 to 8 % protein contents, 3% fat, and 3% fiber (Juliano, 1985). Until recently, rice was considered only a starchy food with abundant quantity of carbohydrates and some amount of protein (Umadevi et al., 2012). Though rice contains small amounts of protein even then it is of high nutritional value (Chaudhary and Tran, 2001). A campaign organized by FAO under the motto “Rice is Life” reveals the importance of rice as primary source of food and it focus on an understanding that rice based systems are necessary for food security, poverty alleviation and better livelihoods. The system of rice intensification (SRI) originated from the uplands of Madagascar during 1980s and the originator was a French Priest Henri de Laulanie. Initially this system has faced many controversies ever since the effectiveness of its methods was confirmed in China and Indonesia seven years ago (Wang et al., 2002; Gani et al., 2002). It is not necessary that rice produces more under flooded conditions (Hatta, 1967). Other studies which have been conducted to evaluate the manipulation of depth and interval of irrigation has shown that rice does not necessarily need a continuously submerged conditions for high yields (Guerra et al., 1998). System of rice intensification has been supported as a set of agronomic management practices for the cultivation of rice from more than a decade as that it offers high yield (Namara et al., 2008; Zhao et al., 2009), decreases the irrigation requirements (Satyanarayana et al., 2007), enhances the productivity of inputs (Sinha and Talati, 2007), is handy for smallholders (Stoop et al., 2002). In case of SRI intermittent irrigation is carried out to keep the soil just moist or saturated while organic matter application is carried out rather using inorganic fertilizers which reflects SRI is more favorable for the environment (Uphoff, 2003). Pak. J. Agri. Sci., Vol. 52(1), 27-36; 2015 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 http://www.pakjas.com.pk EVALUATING THE ROLE OF SEED PRIMING IN IMPROVING THE PERFORMANCE OF NURSERY SEEDLINGS FOR SYSTEM OF RICE INTENSIFICATION Farhan Khalid* 1 , Azraf-Ul-Haq Ahmad 1 , Muhammad Farooq 1 and Ghulam Murtaza 2 1 Department of Agronomy, University of Agriculture, Faisalabad, Pakistan 2 Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, Pakistan * Corresponding author’s email: farhan1727@gmail.com There is a dire need to explore the potential of seed priming in different aged rice nursery seedlings under system of rice intensification. The field experiment was executed to evaluate the role of seed priming in improving the performance of nursery seedlings for system of rice intensification during the 2 nd week of June, 2010 and 2011 at Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan. The experiment was laid out into randomized complete block design with split split plot arrangement having three replications. The experimental treatments were comprised of two rice varieties (Super Basmati and Shaheen Basmati), three seedling ages (2, 3 and 4 weeks old) and seed priming (non-primed seeds; control and primed with 1.5% solution of CaCl 2). The results showed that rice cultivars, seedling age and seed priming significantly improved the leaf area index, crop growth rate, leaf area duration and net assimilation rate during both the years. Two weeks old seedlings performed better than 3 and 4 weeks old seedling by improving tiller production, kernels per panicle, 1000 grain weight, kernel yield, straw yield and harvest index. Two weeks old seedlings raised from seeds osmoprimed with CaCl2 improved kernel quality and remained best by giving higher net benefits (Rs. 136124 & 144933) and marginal rate of return (35 & 39) during the year 2010 and 2011. Key words: SRI, intensification, CaCl2, seedling age, oryza sativa