BIOMASS PARTITIONING AND POTASSIUM ACCUMULATION OF FIVE SORGHUM GENOTYPES UNDER DEFICIENT AND ADEQUATE POTASSIUM NUTRITION

Abstract

Potassium (K) has been reported to positively influence sorghum growth and productivity. This field study was conducted to evaluate the effect of K nutrition on the growth, biomass allocation and K accumulation of five sorghum genotypes. The experiment was launched in a two factor randomized complete block split plot design with three replicates. Five sorghum genotypes were grown at two levels of soil applied K2O, i.e. 0 kg ha-1 (control) and 72 kg K2O ha-1. The crop also received recommended doses of nitrogen (120 kg ha-1) and phosphorus (70 kg ha-1). The results revealed that the two sources of variance highly significantly affected all the growth and yield parameters. Sorghum genotypes did not significantly differ for K accumulation. The interaction between two sources of variance significantly affected biomass allocation of shoot, root and total biomass only, but did not affect on leaf and flower (head) biomass, length of root and flower, number of leaves, shoot and root diameter and K concentration of plants. The genotype Sarokartuho had maximum root biomass, leaf biomass and number of leaves under both the levels of K. The genotype Red Janpur had maximum flower biomass, flower length and K concentration under both the K levels. The genotype Ghotki Turi produced maximum total biomass, shoot biomass, shoot length and shoot diameter under both K conditions, coupled with maximum number of leaves under deficient K condition. The genotype Rehmani had maximum root biomass under K deficiency stress, coupled with maximum root length under both the K regimes. The genotype Kundri had maximum root biomass under K deficiency stress, while maximum root diameter under both the K levels. The study concluded that the sorghum genotypes varied widely for their growth and biomass production, however, this variation was independent of their K accumulation. The sorghum genotype Ghotki Turi appeared to be a potential candidate to perform well both under low and high K input agriculture.

Keywords

• sorghum
• potassium
• genotypic variation
• K-use-efficiency