MANOHAR REDDY , N.SARITHA , A.2019-08-092019-08-092004D7084http://krishikosh.egranth.ac.in/handle/1/5810120609The study on seed dormancy duration and breaking methods in rice genotypes was carried out during kharif; 2002. Seed dormancy of fifty one popular rice cultivars was estimated with a simultaneous study of physical and chemical methods of breaking seed dormancy. The mean seed dormancy among the genotypes varied from cultivar to cultivar (0 - 42 days) indicating the variation due to genetic make up of the seed. The maximum seed dormancy of 42 days was recorded in Vijetha and there was an absolutely no dormancy in seven cultivars viz., Tellahamsa, Erramallelu, Keshava, KMR 3R, Shiva. Kavya and Phalguna. The data on the comparative efficacy of the different physical and chemical treatments used for breaking the seed dormancy indicated that all the methods brought a considerable degree of improvement in germination by eliminating seed dormancy. However, seed treatment with GA3 at all concentrations (100, 250 and 500 ppm) appeared to be the best followed by pre-heat treatment at 40°C for 24 h and seed treatment with HN03 0.3% in breaking the seed dormancy. eed dormancy indicated that seed dormancy was not associated with any of the morpho-physiological characters except L/B ratio of the seed which exhibited negative correlation with dornlancy duration.ennullThesis