This study focused on evaluation of introgressed population for earliness in flowering and productivity under rainfed upland rice ecosystem. The population was derived from inter-varietal cross between early maturing Africa upland land rice WAB-450, an inter-specific derivative as donor and Swarna, a mega rice variety from India, as recurrent parent. One hundred and eighty eight (188) backcross inbred lines (BILs) with the two parents were evaluated during kharif 2011 at Mugad Agricultural Research Station (ARS), University of Agricultural Sciences Dharwad. The BILs showed significant improvement over Swarna for earliness in flowering and productivity under natural rainfed condition. The frequency distribution of days to 50% flowering observed in this study showed continuous variation. The distribution was normal indicating inheritance of a quantitative trait and influence of WAB-450 genome contribution in one backcross in the expression of this trait. The BILs which flower between 90 and 100 days and mature around 120 to 135 days with high yield coupled with other desired traits such as grain quality have been identified for upland rice ecosystem.

Key words: Backcross inbred lines, WAB-450, population, flowering.