Developing and cultivating new promising rice lines with high yield potential and blast disease resistance is an important goal of rice breeding. The study was to evaluate some developed new elite rice lines for high yield, blast resistance, effective resistance genes to Pyricularia grisea and rice stem borer insect as well as assessment of the genetic diversity in these lines using microsatellite markers. Significant differences were found among the studied new promising lines and their parents for yield and its component traits. Promising lines; GZ11190-3-13-1-1 and GZ11190-3-13-4-1 gave the highest grain yield compared with their parents; Giza 178 and GZ6296-12-1-2-1-1 and superiority for all studied traits. Also under this study, twenty six isolates were identified as five main groups i.e., IC, ID, IF, IG and IH, but ID and IH groups were considered the most common race, Pib resistance gene was the most effective gene to blast fungus. Promising lines GZ11190-3-13-1-1 and GZ11190-3-13-4-1 proved resistance for all tested isolates under greenhouse condition and moderately resistant for stem borer insect. For genetic diversity analysis, twenty SSR markers were polymorphic amplifying a total of 102 alleles. Characterization of these markers showed high discriminating power with an average polymorphism information content (PIC) of 0.754. Major allele frequency ranged from 0.475 (RM590) to 0.923 (RM5 and RM5313), with an average of 0.705. The cluster analysis based on microsatellite SSR markers grouped 13 rice genotypes into clear separate groups and was able to reveal close genetic relationships between rice genotypes used in rice breeding program.