Varietal improvement and participatory selection of promising spring rice genotypes by study of the genetic variability, character association between yield traits and farmer preference analysis help in rice breeding for development of best spring rice varieties in western hill of Nepal. This book describes brief procedure to estimate the extent of association of yield attributing traits. It also gives idea to estimate phenotypic and genotypic coefficient of variation and heritability of some yield and yield related traits. Participatory variety selection facilitates development of varieties suitable for marginal soils and farmers' interests. In participatory varietal selection, farmers became a part of selection procedure and testing process in order to incorporate their preferences, which were crucial for the large-scale adoption of the selected varieties.