Indian Journal of Plant Sciences ISSN: 2319–3824 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jps.htm 2014 Vol. 3 (2) April -June, pp. 177-179/Anitalakshmi et al. Research Article © Copyright 2014 | Centre for Info Bio Technology (CIBTech) 177 VARIETAL RESPONSE TO VARIOUS CHEMICAL TESTS FOR THEIR CHARACTERIZATION IN RICE (ORYZA SATIVA L.) V. Anitalakshmi, Rame Gowda, *Sathisha C.S. and Rajendra Prasad. Department of Seed Science and Technology University of Agricultural Sciences, G.K.V.K, Bangalore-65 *Author for Correspondence ABSTRACT Eighteen rice genotypes were grouped on the basis of chemical tests (standard and modified phenol test, GA 3 , 2,4-D and KClO 3 ). Among the chemical tests phenol and modified phenol tests gave the stable results and can be effectively used for cultivar differentiation. 100 ppm GA 3 and 2, 4-D gave more variation in shoot length among the genotypes compared to other concentrations. The study revealed that these tests could be effectively used for determining the varietal purity of rice for routine testing in seed testing laboratories as some of the cultivars showed distinct response to these chemical tests. Key words: Chemical Tests, Characterization, Phenol, KOH, 2,4-D, KClo3, Seed, Rice INTRODUCTION The present trend of continuous release of rice varieties from Central and State Varietal Release Committee has warranted to develop suitable techniques for varietal identification at the laboratory level particularly when the seeds have been submitted for seed purity analysis. Maintenance of genetic purity of varieties is of primary importance for preventing varietal deterioration during successive regeneration cycles and for ensuring varietal performance at an expected level. The chemical tests reveal differences among the seeds and seedlings of different varieties. These tests require virtually no technical expertise or training and can be completed in a relatively short time. The results of these tests are usually distinct, easily interpreted and help in grouping of the genotypes. Therefore, an investigation was carried out to study the response of rice genotypes to various chemical tests to explore the possibility of using these tests for determination of cultivar purity in rice. MATERIAL AND METHODS Source of Seed: Standard phenol test: One hundred (25 x 4) seeds were presoaked in distilled water for 24 hours at 25 + 1C. Then they were transferred on to two layers of Whatman No.1 filter paper saturated with four per cent phenol solution and incubated at 25 + 1C for 24 hours. Based on the intensity of colour they were classified as no change in colour (NC), light brown (LB), brown (BR) and dark brown (DB) according to Jaiswal and Agarwal (1995). Modified phenol test: Modified phenol test was conducted similar to standard phenol test except soaking seeds in CuSO 4 (0.5 %) and FeSO 4 (1%) instead of distilled water. Then based on color reaction of seed coat the genotypes were classified as no change in colour (NC), light brown (LB), brown (BR), dark brown (DB) and black (BL). KOH test: One hundred seeds (25X4) were soaked in KOH solution (4%) for three hours and change in solution colour was observed and the genotypes were classified as no change in colour (NC) and reddish brown (RB). GA 3 test: One hundred seeds (25X4) were presoaked in 25, 50 and 100 ppm GA 3 for a period of 24 hours and germinated as per ISTA (1996). Observations were recorded on 14 th day in terms of increase in shoot length over that of control. 2,4-D test: One hundred seeds (25X4) were soaked in 5, 10 and 15 ppm 2,4-D for a period of 24 hours and germinated as per ISTA (1996). Observations were recorded on 7 th day in terms of decrease in shoot length over that of control.