Potassium use efficiency of different cotton genotypes in two different soils

Cotton is an important and strategic plant. This plant is susceptible to K deficiency. Some plants i.e. cotton has genetic differences in K uptake and use. The objective of this study was to investigate the K uptake and use efficiency of some cotton genotypes in two different soils and, to introduce the superior genotypes. For this purpose, a pot experiment carried out on 20 different cotton genotypes as a factorial in a completely randomized design with three replications. The first factor consisted of 20 cotton genotypes, the second factor was 3 plants growth media which included of washed sand mixed with soils that predominant in smectite (Kordkouy) and illite (Rahmatabad) and control (washed sand without soil). The plants were grown to 40 days and then harvested. The Amounts of dry matter weight and potassium in the leaves, stems and roots were measured. The results showed that the different cotton genotypes have different responses in different cultivation media. Sepid and N2680 genotypes in the Rahmat abad soil, Tabladila in the Kordkoy soil and Golestan in control had the most K uptake but, Khorshid, Armaghan and M16 genotypes showed the least K uptake in the Rahmat abad and Kordkoy soils and in the blank, respectively. The K uptake in the Kordkoy soil to other two treatments (control and Rahmat abad soil) decreased due to the dominant smectite and, followed by high potassium exhaustion. The results indicated that Khorshid, Armaghan and M16 genotypes with the least dry matter weight and the least potassium uptake categorized as an inefficient genotypes group and, NN2A19, N2680, SKT133 and BC244 genotypes with the most dry matter weight and medium potassium uptake considered as an efficient genotypes group. The genotype Sepid with the most dry matter yield and potassium uptake was efficient in potassium uptake but was inefficient in potassium use. The remaining genotypes with average dry matter weight and potassium uptake classified in a medium efficient group.