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The results of testing the International Maize and Wheat Improvement Center’s (CIMMYT’s) hybrid combinations, developed from hybrid 790 F2:3 lines and 10 parental lines, using two testers (CML451 and CLO2450) under optimal and managed drought conditions in Ninh Thuan, Vietnam, show that the average grain yield of the biparental (BP) groups of heterosis groups A and B is, respectively, 2.58-3.65 tons/ha and 2.56-2.76 tons/ha in drought conditions, and 4.24-5.02 tons/ha and 5.41-5.93 tons/ha in wellwatered conditions, respectively. By genotyping eight BP populations with 39,846 single nucleotide polymorphism (SNP) markers, CIMMYT experts identified 15 important gene regions that regulate grain yield associated with 15 SNP markers on chromosomes 3, 4, 5, 6, 7, 8, 9, and 10 which is useful for applying molecular markers in breeding drought-tolerant maize. On that basis, the Maize Research Institute of Vietnam studied and genotyped three populations, including 450 F2 families, with 96 SNPs using the Kompetitive Allele Specific PCR (KASP) genotyping method. The result was that 57 SNP markers related to drought tolerance were found useful to these populations. In addition, 27 F2 families demonstrating drought tolerance and high grain yield were selected as primary materials for breeding maize hybrids tolerant to stresses and adaptive to climate change.