Intra-specific variations among wheat genotypes for phosphorus use efficiency

Phosphorus (P) deficiency in Pakistani soils severely limits the crop production, hence, the development of P-efficient cultivars seems inevitable to uphold the productivity of P-impoverished agricultural systems.Ten wheat genotypes (AA-V1, AA-V2, AA-V3, MSH-3, MSH-5, BWQ-4, EST-28/11, EST-29/9, ESW-9525 and NIA-Sunder) were evaluated for P-efficiency and responsiveness under two phosphorus levels viz., 20 and 200 μM in hydroponic culture. Completely randomized design with two way factorial arrangement was used and the treatments were replicated five times. Seven days old seedlings were shifted to solution culture and grown for four weeks after transplanting. The plants were then harvested for recording growth and phosphorus related attributes.Low P level markedly reduced shoot and root dry weight, P concentration and accumulation in wheat genotypes. However, P utilization index of shoot and root were improved by 30 and 13% at low P supply. Shoot P utilization index was positively correlated (r > 0.43; n = 50) with shoot dry weight and shoot P accumulation at both P levels. Genotypes were grouped into four classes by regressing shoot dry weight at low P level and physiological P-use efficiency. Genotypes AA-V3 and NIA-Sunder were categorized as efficient and responsive (ER) genotypes, while AA-V1, BWQ-4 and EST-28/11 were identified as efficient but non-responsive (ENR). Genotypes AA-V2 and MSH-5 formed the non-efficient but responsive (NER) group. Non-efficient and non-responsive (NENR) category included MSH-3, EST-29/9 and ESW-9525. The results of present study indicated that AA-V3 and NIA-Sunder were the most P-efficient and responsive genotypes as they have the potential to yield more under varying levels of P availability. However, the results should be confirmed under filed conditions.