QUALIDADE DO GRÃO FORMADO NO COLMO PRINCIPAL E NOS PERFILHOS DE PLANTAS DE ARROZ ( Oryza sativa, L.) EM FUNÇÃO DE DIFERENTES ARRANJOS DE DISTRIBUIÇÃO DE PLANTAS NO SOLO QUALITY OF THE GRAIN FORMED EITHER IN THE PRIMARY STEM OR SECONDARY STEMS OF THE RICE PLANT (Oryza sativa L.) AS A FUNCTION DIFFERENT SYSTEM OF PLANTS DISTRIBUTION ON SOIL

Similar to crop yield (kg.ha -1 ) grain quality is also fundamental in rice production. However, grain quality determining factors remain to be better identified and understood. In this context, grains from the primary and secondary stem of rice plants (BRS Firmeza and BRS Pelotas cultivars), cultivated under six different arrays of plant distribution on soil (two distances between plant rows (12.5 and 17.5 cm) combined with three planting densities (90, 120 and 150 kg.ha -1 )), were evaluated in terms of whole grain, white-core grain and chalky grain occurrence, amylose content, and starch gelatinization temperature. The fieldwork was developed at Embrapa Clima Temperado, a research center in Pelotas, RS, Brazil, in the agricultural years of 2006-2007 and 2007-2008. For both rice cultivars, for the majority of plant arrays tested, the primary stem produced more whole grains and less white-core and chalky grains than the secondary stem. Grains from the primary stem were not different from grains from the secondary stem in terms of amylose content and starch gelatinization temperature.