Genetic variation affecting agronomic traits in sugarcane in response to high and low phosphorus availability

Abstract

Low P availability in the soils of tropical regions is one of the main factors limiting agricultural production. Improving the efficiency of P use in plants is recognized as a less onerous and more sustainable method of maintaining satisfactory production in P-deficient soil. The aims of this study were to assess the existence of genetic variability for P use efficiency in sugarcane (Saccharum spp.) and to identify useful variables for the selection of efficient and responsive genotypes under low- and high-P conditions. The experiment was conducted in a greenhouse with 23 genotypes and two rates of P (40 and 240 kg ha–1) for 8 mo. We derived variables related to P absorption, accumulation, and utilization efficiency (PUE). Genotypes with similar productivities under high-P conditions varied widely in P-deficient soil. By measuring the production of dry aboveground mass, efficient genotypes under low-P conditions could be identified and classified regarding their efficiency and responsiveness to P. It was possible to classify the genotypes according to their P absorption efficiency (PAE) using the recovery rate of P and the root efficiency ratio. Regarding P accumulation, there was greater accumulation in the roots than in the stalks or leaves under low P. Under optimal P conditions, PUE measurements in the stalks and in the aboveground parts of the plant could be used to effectively select genotypes with superior nutrient use. Under low-P conditions, the PAE was more important in genotype selection.