The possible alteration in plant growth, productivity and phosphorus (P) demand of wheat under rising atmospheric CO2 and temperature is expected to influence the partitioning of P to different plant parts of wheat. A phytotron experiment was conducted to study the effects of elevated atmospheric CO2 (650 µmol mol-1) and elevated temperature (ambient + 3 °C) on phosphorus harvest index of wheat at various levels (control, 100% and 200% of recommended P) of P fertilization. While there was a slight increase (5.6%) in P harvest index of wheat under elevated CO2, the reverse trend (12.7% decline) was observed under elevated temperature with no consistent effect at various levels of P fertilization. Interestingly, there was a moderate decline (7.7%) in P harvest index of wheat under combined elevation of CO2 and temperature as compared to their ambient combination. The results suggest that temperature could be the dominant factor as compared to the atmospheric CO2 in deciding the overall impact of projected increase in atmospheric CO2 and temperature on P harvest index of wheat. As there is logically possible relationship between P harvest index of wheat and various physical and nutritional qualities of wheat grains such as grain Zn and Fe content and their bio-availability, grain protein content, seedling vigour, etc., the decline in wheat’s P harvest index under projected levels of CO2 and temperature in our study underscores the need of undertaking elaborate experimentations to investigate the probable effects of climate change on quality parameters associated with P harvest index of wheat.
Climate change, Elevated CO2, Global warming, Grain nutritional quality, Phosphorus demand, Phosphorus partitioning