Very little is known of phosphorus availability for upland rice. The objective of this work was to evaluate root growth of upland rice cultivars in different conditions of phosphorus availability. The experiment was carried out in greenhouse, in a completely randomized design, as a 4 x 4 factorial, with four doses of P (0, 50, 100 and 200 mg dm-3) and four cultivars: Maravilha (modern group), IAC 201, IAC 202 and Carajás (middle group). The Carajás root system grew more in low availability of P than other cultivars. In low availability of P the cultivars IAC 201 and IAC 202 priorized root system growth to aerial growth . The Maravilha cultivar needs high Plevels to reach maximum growth. In low availability of P the upland rice cultivars decreased root diameter.
fertilization; root length; dry matter; oryza sativa L.
