Influence of rising atmospheric CO2 and phosphorus nutrition on the grain yield and quality of rice (Oryza sativa cv. Jarrah)
1996
Seneweera, S. | Blakeney, A. | Milham, P. | Basra, A.S. | Barlow, E.W.R. | Conroy, J.
Raising the atmospheric CO2 concentration from 350 microliter of CO2 per liter to a level expected by the end of the next century (700 microliter/L) influenced both the grain yield and quality of the short-duration rice (Oryza sativa) cultivar, Jarrah. Yield was enhanced by up to 58%, primarily due to an increase in grain number, although grain size was also greater at high CO2. Varying the supply of phosphorus influenced the magnitude of the CO2 response with greatest responses occurring at medium rather than luxury or low phosphorus supplies. However, yield enhancement by high CO2 was observed even when phosphorus supply was severely growth limiting. Chemical (amylose and nutrient concentration) and physical (relative paste viscosity) measurements made on the ground grain indicated that cooked rice grain from plants grown under high levels of CO2 would be firmer. The nutritive value of grain was also changed at high CO2 due to a reduction in grain nitrogen and, therefore protein concentration. However, total nitrogen content per grain was unaffected by high CO2. In contrast, phosphorus content per grain was greater at high CO2 and there was a strong correlation between magnesium and phosphorus concentrations. These results indicate that there is a need to plan for the inevitable rise in atmospheric CO2 concentration by selecting genotypes that will maintain suitable quality characteristic under global change.
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