~ 2397 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(1): 2397-2400 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(1): 2397-2400 Received: 15-11-2017 Accepted: 16-12-2017 Ashish Kumar Panigrahi Department of Plant Molecular Biology and Bioinformatics, TNAU, Coimbatore, Tamil Nadu, India M Bharathi Department of Plant Molecular Biology and Bioinformatics, TNAU, Coimbatore, Tamil Nadu, India N Kumaravadivel Department of Plant Molecular Biology and Bioinformatics, TNAU, Coimbatore, Tamil Nadu, India Correspondence Ashish Kumar Panigrahi Department of Plant Molecular Biology and Bioinformatics, TNAU, Coimbatore, Tamil Nadu, India Genetic variability and character association studies in advanced backcross generation of rice ( Oryza sativa L.) Ashish Kumar Panigrahi, M Bharathi and N Kumaravadivel Abstract An experiment was designed to know the genetic variability, heritability, genetic advance and character association among the lines homozygous dominant for gall midge resistance genes Gm1 and Gm4 in the genetic background of ADT 38 variety of rice in advanced backcrossed (BC1F5) generation of rice. The Phenotypic coefficient of variation (PCV) was higher than the genotypic coefficient of variation (GCV) for all the characters studied. High heritability coupled with high genetic advance as percent of mean was registered for character like hundred grain weight. Highly significant positive correlation with single plant yield was exhibited by traits like number of tillers, number of productive tillers and number of filled grain per panicle. Positive direct effect was exhibited by number of tillers, number of filled grains per panicle and hundred grain weight towards single plant yield. These characters will be useful for further breeding. Keywords: phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability (h 2 ), genetic advance (GA), correlation, direct effect Introduction Rice (Oryza sativa L.) being the most important cereal food crops in the world which forms the staple diet of 2.7 billion people (Tannidi et al., 2016) [29] . Around 32- 59% of the dietary energy and 25-44% of the dietary protein was obtained from rice in more than 39 countries (Prabhu et al., 2017) [22] . Rice crop losses due to biotic stresses are estimated at 1 to 85 per cent (Rola and Widawsky, 1998) [23] . India has about 433.88 lakh hactre of area under rice with an annual production of 104.32 million ton presently (GOI 2016-17). It is estimated that India needs to produce 120 millions tonnes of rice by 2030 to feed its projected one and half billion plus population by then (Adhya 2011) [1] . The Asian rice gall midge, Orseolia oryzae (Wood- Mason) (Diptera: Cecidomyiidae), a major pest of rice (Oryza sativa L.), forms leaf-sheath gall called ‘silver shoot’. It is the third most economically important pest of rice in India causing an average annual yield loss worth US$ 80 million (Bentur et al., 2003) [5] . Genetic parameter such as heritability offers the information of transmissibility of characters from one generation to consecutive generations (Bello et al., 2012) [4] . High heritability with high genetic advance (%) of mean is used to predict the performance of genotype/progeny for yield and yield contributing traits (Singh et al., 2011 and Govintharaj et al., 2016) [27, 10] . Material and Methods The present investigation comprised of evaluation of BC 1 F 5 population having gall midge resistance genes Gm1 and Gm4 in the background of ADT 38 variety of rice along with un- pyramided ADT 38 as check. The seed material for the present study was obtained from plants homozygous dominant for Gm1 and Gm4 in the BC 1 F 4 population of the ADT 38. Previously the gene pyramiding being done into ADT 38 background where Kavya and Abhaya being the donor for Gm1 and Gm4 gall midge resistance gene respectively. The pyramided ADT 38 (Gm1+ Gm4) backcrossed by taking ADT 38 as recurrent parent and selfed upto F 4 generation. The field experiment was conducted in Randomized Design, with 5 replications by following a standard spacing of 20 cm x 20 cm. The standard agronomical practices were followed to grow healthy crop at wet lands, Tamil Nadu Agricultural University, Coimbatore during the growing season of 2013- 2014. The mean values of 5 replications were used for statistical analysis. The observation were recorded on eleven quantitative traits viz, days to fifty per cent flowering (DFF), plant height (PH), number of tillers (NT), number of productive tillers (NPT), panicle length (PL), number of filled grains (NFG), grain length (GL), grain width (GW), grain length/grain width ratio (GL/GW), hundred grain weight (HGW) and single plant yield (SPY) The descriptive statistics were estimated for each trait studied with the help of MS – EXCEL