International Journal of Agricultural Research1816-48972152-2553Academic Journals Inc.10.3923/ijar.2006.509.521Oryza sativa L.) For Lowland Drought Situation by Association Analyses]]>ManickaveluA. GnanamalarR. P.NadarajanN. GaneshS. K.6200616Rice is the principle food crop and is drastically affected by drought. Breeding for drought tolerance is a challenging task because of the complexity of the component traits, screening technique, environmental factors and their interaction. The major set back in drought tolerance breeding is the poor understanding of genetics and inheritance of drought tolerance traits and complete ignorance about the relationship between traits of physiological drought tolerance and plant productivity under stress. Present study consisted of BIPs, F3 and RIL population screnned under drought condition to know the association nature. Association analysis in BIPs revealed that, if selection pressure is given on the positive side for days to 70% RWC, dry root weight, harvest index, root/shoot ratio and biomass yield and negative side for leaf rolling and leaf drying, it will result in high grain yield under drought situations. From F3 studies it is concluded that selection pressure should be given on harvest index and productive tillers per plant in positive direction and plant height and leaf drying in negative direction for yield improvement in drought resistance breeding programme. The association analysis of RILs showed that, to harness high yield combined with drought tolerance, breeders should give selection pressure on days to 70% RWC, panicle length, grains per panicle, harvest index, biomass yield, root/shoot ratio and root length in positive direction and leaf rolling, leaf drying and drought recovery rate in negative direction. Association studies in three breeding materials combinedly pointed out that there is much scope for selecting high yielding genotypes with drought tolerance in rice, if selection pressure is exerted on days to 70% RWC, root/shoot ratio, biomass yield and harvest index and low scores of leaf rolling and leaf drying.]]>Atlin, G., 20032003pp: 14-22pp: 14-22Bala, A., 200188356357Balan, A., A.R. Muthiah and S.N.M. Ramachandraboopathi, 19998679Comstock, R.E. and H.F. Robinson,19484254266Dewey, D.R. and K.H. Lu,195951515518Fukai, S. and M. Cooper,19961996pp: 123-149pp: 123-149Gomez, S.M. and P. Rangasamy, 2002Oryza sativa L.]]>193334Goulden, C.H., 1952Jeena, H.S. and S.C. Mani, 199027214216Jongdee, B., S. Fukai and M. Cooper,200276153163Lenka, D. and B. Misra, 197343376379Lilley, J.M. and S. Fukai,199437205213Pantuwan, G., S. Fukai, M. Cooper, S. Rajatasereekal and J.C. O'Toole, 200273153168Raju, C.H.S., M.V.B. Rao and A. Sundarshanam, 200390621624Rao, S.S. and R.R. Saxena,1999368284Shanthi, R.M.,1989Oryza sativa L.]]>1989Singh, R.P., C.B. Singh and S.N. Shrivastava, 19949163170Sreedhar, A.,2000Oryza sativa L. ]]>2000Thangaraj, M. and V. Sivasubramanian, 199027493495Tomar, J.B. and S.C. Prasad, 1996Oryza sativa L. varieties.]]>66459465Tyagi, A., K. Narendrakumar and R.K. Sairam,19994302306Unnikrishnan, K.V.,19861986Venkataramana, R. and S. Hittalmani, 20002 segregating populations of rice Oryza sativa L. ]]>20206208Yunus, M. and R.S. Paroda,198262337343