Appropriate boron (B) availability in soils favors root growth, and a sufficient supply of this micronutrient is very important for adequate rice development and yield in upland fields, depending on the cultivars and soil type. This study aimed at evaluating the influence of B addition on growth of roots and shoot of three upland rice cultivars. The experiment was carried out in a greenhouse, in 10 L pots containing 8 kg of an Hapludox; the experiment was in a completely random 3 x 3 factorial design, with four replications. The treatments consisted of three rice cultivars (Caiapó, Primavera, and Maravilha) and three B rates (0, 3 and 6 mg dm-3), as borax. The B rate of 6 mg dm-3 boron was deleterious to dry matter yield of both roots and shoot in upland rice. Besides the greater absorption capacity, cultivar Maravilha was more tolerant to high B doses in the soil, thus root length, diameter and surface were not negatively affected.
Oryza sativa; absorption; root
