Interação genótipo x ambiente em ensaios de valor de cultivo e uso em cultivares de arroz vermelho

Abstract

Red rice is a special type of rice in which the grains have the reddish-colored pericarp that occurs due to the presence of a dominant character that is controlled by the Rd gene on chromosome 1 and Rc on chromosome 7 when these genes are present together Rc_Rd_) there is red grain production. Red rice has greater added value and, consequently, greater market value when compared to white rice, mainly due to its functional characteristics, such as high antioxidant content. A red rice cultivar capable of presenting great productivity, together with the high market value of this product, suggests that this crop may appear as an alternative production for producers who do not have large areas and who need to add value to their production, seeking to increase their productivity income. Research on the cultivation of red rice is still scarce, there is a need to expand the study of the adaptability and stability of the existing red rice strains in order to launch new cultivars, in order to make possible the recommendation of this cultivation for different regions and different production systems. The objective of this study was to morphologically describe two cultivars of red rice and to evaluate their respective agronomic behaviors, comparing them to two cultivars of white rice, in three locations and two consecutive years, in the state of Rio de Janeiro. The experiments were carried out during the agricultural years of 2016/2017 and 2017/2018 in the municipalities of Campos dos Goytacazes, Seropédica and Pinheiral, and were conducted in a rainfed system, with supplementary irrigation, and under organic production management. The morphological characteristics were evaluated: flag feaf angle, leaf color, stem length, presence of edges, panicle length, apiculus color, glumelle color, grain length and grain shape; and the following agronomic characteristics: viable panicles per square meter, panicle spikelets, spikelet fertility, 100 spikelet weight, yield, stem length, panicle length, plant height, cultural cycle and mean flowering; in addition, the classification of the grain and the milling yield and whole grains were evaluated. The experimental design was a randomized block design, with four treatments and five replications. The treatments were registered cultivars of white rice, BRS Esmeralda and IAC 201 and the traditional cultivars of red rice, ENA-AR1601 and Virginia. The data were submitted to analysis of variance, individual for each location and year, the means were compared by the Tukey test (p <0.05), then the analysis of the variance was performed, considering the four cultivars, the three places and the two years A study was carried out in order to know the behavior of the cultivars in the different locations, where the "Productivity" characteristic was evaluated. It was carried out the stratification of environments, the decomposition of interaction in simple parts and estimated the parameters of stability and adaptability. The cultivars of red rice differ to the lengths of stem and panicle, to the presence of edges and to the shape of the grain, presented excellent productive performance and yield of processing. GxA interaction was identified, with a predominance of the simple type and two groups were formed from the stratification of environments. The cultivars ENA-AR1601, Virgínia and BRS Esmeralda presented broad adaptability and high stability.