Suscetibilidade à quebra e qualidade tecnológica de genótipos de arroz submetidos ao atraso da colheita

Abstract

Most of the rice genotypes grown in southern Brazil present an ideal harvest point between 30 and 35 days after full flowering, and when the grains have a moisture content in the range of 16 to 22. However, environmental and/or operational conditions do not always allow for the harvest at the optimal time, making the grains often remain in the field for a longer time with variable environmental conditions. This delay period can lead to a reduction in the industrial quality of rice grains, especially in the whole grain yield, due to the susceptibility to breakage during industrial processing associated with the presence of cracks in the grains. Climatic conditions are uncontrollable and influence rice quality, making it necessary to develop and study rice varieties resistant or tolerant to the formation of cracks from the field to storage. Therefore, this study aimed to evaluate the technological quality and susceptibility to breakage of eight rice genotypes based on the effects of harvest delay. With these relations, ideal harvest points were estimated to obtain the maximum whole grain yield of the genotypes. It was concluded that the delay in harvest tends to increase cracked grains and reduce the degree of moisture and whole grain yield. The lowest yield of wholes occurred at 90 days after flowering (DAF) and the highest between 30 and 35 DAF and optimum moisture content between 18.6 and 21%. The effects of the delay in harvest are very significant, even for genotypes with high yield of head in the optimal harvest period.