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.