Biomass Production and Phosphorus-Use-Efficiency of Five High-Yielding Wheat Varieties of Sindh at Early Growth Stage

Phosphorus (P) is a finite resource, and improving P-use efficiency is important for crop production under limited P availability. This study compared five modern wheat varieties (Benazir, Khirman, Kiran, Moomal and Sindhu) for growth, biomass production, P acquisition and P-use efficiency under deficient (P0) and adequate P supply (P90; 90 kg P₂O₅ ha⁻¹). The field experiment was conducted in a randomized complete block split-plot design with three replications. Compared with P0, P90 increased shoot fresh weight, shoot length, root length, and root P concentration by 18.2%, 18.8%, 10.7% and 3.8%, respectively, while P level had no significant effect on several other traits. The varieties differed considerably in biomass production and P-related traits. Moomal produced the highest shoot and root fresh and dry weights, with 64.1–218.8% higher values than the respective lowest-performing varieties and also had the highest shoot P accumulation and shoot P-use efficiency. Kiran recorded the highest root P accumulation and root P-use efficiency, and its P-efficiency ratio was 19.2% higher than the mean of the five varieties. Likewise, Moomal maintained relatively high root P accumulation under P deficiency, indicating its better ability to acquire P under limited availability. In conclusion, both Moomal and Kiran appeared to have efficient P relations as compared to their counterparts under study. Moomal particularly appeared to have highest P efficiency under limited P supply.