Abstract: Tabacco (Nicotiana tabacum) has a relatively high requirement for potassium (K). The difference in root characteristics and ability to release K from minerals of fluecured tobacco in four genotypes ND202, NC628, G28 and NC628×ND202 were analyzed. The results showed that the more available K released from minerals by roots, the more K would be accumulated by plants. ND202, which was Kenriched genotype, had well developed root system and was easily influenced by K content in the environment. Compared with ND202, NC628 significantly enhanced the effectiveness of K in substrate by releasing K from minerals, though the ability to absorb K was weak. Moreover, the hybrid of NC628×ND202 had a higher ability to release K and to tolerate lowlevel K than maternal parent. It was higher in dry matter accumulation and K enrichment than male parent. So hybridization had the utility value in highK variety cultivation. These results provided evidence that parents should have the ability to enhance available K from soil besides the high combining ability for breeding the highK variety.