Grain quality of upland rice cultivars in response to cropping systems in the Brazilian tropical savanna

The industrial quality of grain is an important parameter to determine the commercial value of rice and can be influenced by water availability and type of cultivar. The present study aimed to evaluate the milling yield as well as the protein and nutrient contents of polished grains originated from two upland rice cultivars grown under rainfed and sprinkler-irrigated conditions. A randomized block design was used in a split-plot arrangement with eight replicates. Plots consisted of two cropping systems ( rainfed and sprinkler-irrigated) with subplots consisting of two cultivars recommended for upland ecosystems (IAC 201 and Carajas). The sprinkler irrigation system increased upland rice milling (8.0%) and head rice yield (23.7%), for years with hot and dry weather spells occurring during the reproductive and maturation stages. Under conditions of lower water availability, the Carajas cultivar showed a milled yield value 5.1% higher than that of cultivar IAC 201. Lower water availability provided increases in protein, N, P, Ca, Mg, Fe, and Zn contents but reductions in S and Cu in the polished grains. Cultivars IAC 201 and Carajas had similar nutrient contents in the polished grains.