February, 2014 Research in Environment and Life Sciences 53 Identification of restorers and maintainers for different WA CMS lines in rice (Oryza sativa L.) P. K. Bhati, S. K. Singh*, Amita Sharma and S. Y. Dhurai Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi-221005 (India) *e-mail: shravanranchi@yahoo.co.in (Received: September 18, 2013; Revised received: December 24, 2013; Accepted: December 26, 2013) Abstract: The present observations revealed that F 1 hybrids produced by crossing 40 different rice genotypes with 2 CMS lines (IR79156A and Pusa 6A) behaved differently with regard to pollen fertility. Out of the 80 F 1 hybrids, 12 were completely sterile and 22 completely fertile. The remaining 46 hybrids expressed varying degrees of fertility, within the range of partial restorers (21) and partial maintainers (25). Genotypes; IET 21519, IET 22218, IET 22228, IET 22202, IET 21542, Sarju- 52, BPT 5204 and MTU-7029 produced higher fertile hybrids and are hence considered as common effective restorers for both the CMS lines. Genotypes IET 20524, RPBIO-226 and HUR-8-1 were found to be effective restorer for only IR79156A whereas; NDR-359, IDR763 and Type-3 were found to be effective restorer for CMS line Pusa 6A. These restorer genotypes may be tested for heterosis for development of new rice hybrids. HUR-105 and Pant Dhan-4 produced sterile hybrids when crossed with IR79156A. Pant Dhan-12 and Vandana produced sterile hybrids when crossed with Pusa 6A. Four genotypes (IET 22237, NDR-97, Nagina-22 and Karahani) produced sterile hybrids when crossed with both the CMS lines, IR79156A and Pusa 6A. These genotypes may be used for development of new male sterile lines. Key words: CMS lines, fertility restorers, hybrid rice, maintainer, wild abortive  2014 RELS ISSN: 0974-4908 http://rels.comxa.com Res. Environ. Life Sci. rel_sci@yahoo.com 7(1) 53-56 (2014) Introduction Rice is one of the most important staple crops of India. It contributes to total food grain and cereal production of the country to nearly 43% and 46% respectively. In India, rice is being grown in 42.86 million hectare area with production of 104.32 million tonnes and productivity of 24.34 q/ha (Foreign Agriculture Services/USDA, Office of Global analysis, April 2012). The population of India, is still growing at higher rate, therefore to meet the demand of increasing population, the country has to enhance its rice production up to 135 million tons by 2020. Among several genetic options available to increase the yield, hybrid rice technology is one the strongest tools. But, to exploit this technology, male sterility is a prerequisite. Use of CMS lines and restorer lines which are diverged and locally adapted will not only increase the nuclear diversity but would also help to prevent genetic vulnerability due to the use of a single CMS source (Pradhan et al ., 1992). The restorers and maintainers for WA cytoplasm were reported earlier by Rosamma and Vijayakumar (2005), Sabar et al. (2007), Akhter et al . (2008), Das et al. (2012), Khan et al. (2012), Krishnalatha and Sharma (2012), Sharma et al. (2012), Soni et al. (2012) and Singh et al. (2013). The purpose of diversification requires search for new maintainers and restorers. Hence, the present investigation was undertaken with an objective to identify different restorers and maintainers for three CMS lines from among the local and high yielding rice genotypes. Materials and Methods The experimental material consisting of 80 F 1 hybrids and their parental lines and 2 CMS lines (IR79156A and Pusa6A) were grown in single row of 4.0 m with three replications in Randomized Block Design with spacing of 20 x 15 cm during Rabi 2012-2013 at Central Rice Research Institute (CRRI), Cuttack, Odisha, India. The investigation was undertaken to estimate pollen and spikelet fertility to identify restorers and maintainers. The purpose of identification of maintainers was to isolate locally adopted genotypes which may be converted into new CMS lines through repeated backcross breeding, while the purpose of identification of restorers was to find out suitable fertility restorers among the locally adapted varieties for the existing CMS lines as a short term strategy for hybrid breeding programme. The pollen and spikelet fertility percentage were used as the fertility index Babu et. al. (2010). For pollen fertility, spikelets were collected from the panicle at the flowering stage. Mature anthers from 5 randomly selected spikelets were squashed, smeared and stained with 1% Iodine Potassium Iodide (IKI) solution and examined under light microscope. Pollen grains were counted at three different spots in the microscopic field. Stained, well-filled and round pollen grains were counted as fertile (viable), while unstained, shriveled and empty pollen grains were considered as sterile (non viable). Pollen viability was calculated and expressed in percentage as: