Performance of different cultivars in direct seeded rice (Oryza sativa L.) in response to various seeding densities

Optimum seeding density is necessary to achieve the production potential of a cultivar in all crops. To investigate the performance of different cultivars in direct seeded rice in response to various seeding densities, a field experiment was conducted at Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan during the kharif 2012. The experiment was laid out in randomized complete block design (RCBD) under factorial arrangement with three replications. Super Basmati and KSK-133 were sown using seeding densities of 30, 45, 60 and 75 kg per ha. Results indicated that leaf area indices, leaf area duration, crop growth rate, total dry matter accumulation and net assimilation rate varied among rice cultivars as well as various seeding densities. The growth of rice at seeding density of 75 kg per ha, was higher than rest of treatments. The response of rice yield and its components like number of productive tillers, number of branches per panicles, number of kernels per panicle and 1000-kernal weight differed significantly under the influence of cultivars and various seeding densities. Seeding density of 75 kg per ha, remained superior for both rice cultivars regarding final yield. This treatment furnished kernel yields of 3.83 and 5.49 t per ha, in fine and coarse rice, respectively which were significantly higher than other treatments. However, kernel quality was improved in terms of lower number of sterile, abortive, opaque and chalky kernels at lower seeding densities (30 kg per ha). Nonetheless, Water absorption ratio was also higher in these kernels. Higher net return (Rs. 69426 per ha) was associated with Super Basmati sown at 75 kg per ha. Based on these findings, it is concluded that using seeding density of 75 kg per ha, for direct seeded fine and coarse rice cultivars is beneficial in terms of better growth and higher yield but kernel quality is reduced by increasing the seeding density.