Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2002.1006.1009NuruzzamanM. AlamM. F. M. G. Ahmed A.M. Shohael M.K. Biswas M.R. Amin M.M. Hossain 102002510Genetic variability was studied for eight quantitative traits in fourteen parental lines of hybrid rice. The characters were plant height, flag leaf initiation day, first panicle initiation day, days to 100% flowering, days to maturity, grain yield/10 hills, spikelet fertility/10 panicles and no. of effective tillers/hill. Two additional characters (flag leaf length and spikelet length) were included in heterosis study. In general high component of variation and coefficient of variability were observed for most of the characters. The highest component of variation, coefficient of variability and heritability were noticed in grain yield/10 hills. Characters those with high genetic variability and genetic advance were considered to be important for selecting the desirable lines. Heterosis was studied in ten F1 lines for 10 characters. In general, the hybrids performed significantly better than the respective parents. Mid parent, standard variety and better parent heterosis were observed for all the characters under study. In comparison of F1 hybrids with their respective mid parent, standard variety and better parent showed significant heterosis for most of the studied characters. Among the 10 hybrids three lines viz., IR62829AxIR62036-222-3-3-1-2R, IR58025AxIR61614-38-19-3-2R and IR68888AxIR56381-139-2-2R exhibited the highest heterosis in grain yield/10 hills. In conclusion, there was an ample scope for developing suitable hybrid rice from the studied parental lines as the hybrids exhibited vigour and earliness.]]>Alam, M.F., A.K.M.A.R. Siddiqui, K.M. Kabir and A. Quasem,1998Vigna unguiculata L. Walp.).]]>17277Alam, M.F., M.M. Rahman and K.M. Kabir,1989Curcuma longa L.).]]>23740Alzona, A.V. and M.A. Arraudeau,1995171313Burton, W.G. and E.H. Devane,1953Festuca arundinacea) from replicated clonal material.]]>45478481Davenport, C.B.,190828454455East, E.M.,193621375397Griffing, B.,1990126753767Hanna, H.Y. and T.P. Hernandez,197914120120Hanson, C.H., H.F. Robinson and R.E. Comstock,195648268272Johnson, H.W., H.F. Robinson and R.E. Comstock,195547314318Johnson, T.E. and E.W. Hutchinson,1993Caenorhabditis elegans.]]>134465474Julfiquar, A.W. and N.M. Tepora,19941 hybrid rice (Oryza sativa L.).]]>123036Khaleque, M.A., O.I. Joarder and A.M. Eunus,1977Oryza sativa L.).]]>4137145Ling, X.L., Y.Li and M.J. Wang,198625460Popova, D., M. Konstantinova and N. Petrova,19801 of tomato (Lycopersicon esculentum Mill.).]]>503838Rahman, M.M., M.F. Alam, K.M. Kabir and M.A. Quasem,1988Lablab purpureus L. Seet.).]]>1123128Singh, A.K., N.C. Gautam and K. Singh,1985Lablab purpureus).]]>42252257Singh, B., V.P. Gupta and P.K. Gupta,1986Raphanus sativus L.).]]>43242247Singh, J. and B. Singh,1984Raphanus sativus L.).]]>21174179Xiao, J., J. Li, L. Yuan and S.D. Tanksley,1995140745754Zhang, Q., Y.J. Gao, S.H. Yang, R.A. Ragab, M.A.S. Maroof and Z.B. Li,199489185192Comstock, R.E. and H.F. Robinson,1952pp: 494-516pp: 494-516Hawlader, M.S.H.,19951995Virmani, S.S.,19871987pp: 35-53pp: 35-53Virmani, S.S., J.B. Young, H.P. Moon, I. Kumar and J.C. Finn,1991pp: 12pp: 12Virmani, S.S., B.C. Viraktamath, C.L. Casal, R.S. Toledo, M.T. Lopez and J.O. Manalo,1997Pages: 151Pages: 151