Background and aim: Developing genotypes with enhanced performance under phosphorus (P) deficiency can be described as an approach to improving production sustainability. This study investigated the physiological responses of sugarcane varieties to varying P availability and the plant traits...

Background and aim: Developing genotypes with enhanced performance under phosphorus (P) deficiency can be described as an approach to improving production sustainability. This study investigated the physiological responses of sugarcane varieties to varying P availability and the plant traits contributing to P efficiency (shoot dry matter production under low P availability).
Methods: Sugarcane varieties IACSP94-2101, IACSP95-5000, RB86-7515, IAC91-1099, IACSP94-2094 and IAC87-3396 were grown under low (25 mg P kg−1 soil) and high (400 mg P kg−1 soil) P supply, and the leaf gas exchange, photochemical activity, plant growth and P uptake were evaluated.
Results: The sugarcane varieties responded distinctly to a low P supply, as indicated by differences in root and shoot growth, leaf area, net CO2 assimilation, photosynthetic P utilization efficiency, leaf P concentration and P uptake. The following ranking was obtained for P efficiency: IACSP94-2094 = IACSP95-5000 > IAC87-3396 = RB86-7515 = IACSP94-2101 = IAC91-1099.
Conclusion: Greater leaf area, net CO2 assimilation and P acquisition efficiency were combined in the more P-efficient varieties but not in the less efficient ones. Although it was not possible to separate cause and effect, such finding might be explained by the positive effect of improved leaf P concentration on leaf area and net CO2 assimilation, which in turn contributed to sustaining improved plant performance under a low P supply

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2011/18446-0

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