Effect of Selection for High Yield, Drought and Salinity Tolerances on Yield-Related Traits in Rice (Oryza sativa L.) Preliminary Identification of Genetic Overlaps between Sheath Blight Resistance and Drought Tolerance in the Introgression Lines from Directional Selection Genetic Overlap of Drought-Tolerance Loci between Germination Stage and Seedling Stage Analyzed Using Introgression Lines in Soybean