Estimates of genetic parameters and morphological characterization of red and white rice hybrids

Rice is one of the most widely grown cereals on the planet. It is present in all continents, accounting for 30% of the world’s cereal production. In Brazil, rice has social and economic importance, because the country is the largest western producer of the grain, where it is consumed daily in all regions. Although red rice is an invasive plant in white rice fields, it is important due to its nutritional characteristics. Some traits need to be improved, in those genotypes. Cross‐pollination is a technique that consists of crossing between plants showing desirable traits in a breeding program. After successive self-pollinations, it is possible to select lines that encompass all those traits. Therefore, the present study proposes to compare morphological traits and estimate genetic parameters between genotypes of red rice and white rice. The experiment was conducted at the UFRRJ campus in Seropédica - RJ, in the 2017/2018 crop year. Two red rice genotypes (‘ENA AR-1601’ and ‘Virgínia’), one white rice genotype (‘BRS Esmeralda’), and the ‘Vírgínia’ × ‘BRS Esmeralda’ and ‘ENA AR-1601’ × ‘Virgínia’ crosses were evaluated. The following traits were analyzed: flag-leaf angle, panicle length, stem length, plant height, grain thickness, grain length, number of tillers, leaf thickness, and stem diameter. A randomized-block experimental design with four replicates was adopted. After analysis of variance was performed and estimates of the genetic parameters of coefficient of genotypic determination (H2), genetic coefficient of variation (CVg), and experimental coefficient of variation (CVe) were obtained, means wee compared by Tukey’s test at the 5% probability level. The trait that showed the lowest H2 was number of tillers (29.87%). The hybrid from the cross between ‘ENA AR-1601’ and ‘Virgínia’ had the greatest panicle and stem lengths and, consequently, the greatest plant height. Plant height showed a high H2 value (97.42%). It is possible to select red rice genotypes with a lower plant height by crossing red rice and white rice genotypes.