Relationship among root characteristics and differential potassium uptake and use efficiency of selected cotton genotypes under potassium deficiency stress

Potassium (k) uptake and k use efficiency are the most important characters of plant genotypes that determine their biomass production under k deficiency stress. this study reports the influence of some important root characters on the k uptake and use efficiency of three pre-selected cotton genotypes under k deficiency stress. these genotypes included cim-506,niab-78 and nibge-2,selected on the basis of their differential k use efficiency i.e.,low,medium and high,respectively. cotton genotypes significantly (p<0.01) differed for their k use efficiency,k uptake of shoot,root and on total basis,tap-root length,lateral root number and specific k absorption rate based on tap root length. while,k accumulation rate,k translocation efficiency,k transport rate and specific k absorption rate based on root dry weight were non-significant. the genotype nibge-2 was the most tolerant genotype to k deficiency stress and performed best for all the parameters studied followed by niab-78 and cim-506. a significant correlation was observed between k use efficiency and k uptake of cotton genotypes. the root characteristics viz.,tap root length,lateral root number,k accumulation rate and specific k absorption rate directly influence both k uptake and use efficiency of cotton under deficient k condition. k translocation rate and specific k absorption rate,based on root dry weight,directly influence total k uptake but not k use efficiency. these physio-morphological root traits of cotton are highly important while breeding for k-use-efficient cotton genotypes.