Seleção de linhas puras dentro da cultivar de aveia preta (Avena strigosa Schreb) IAPAR 61

Abstract

Even thirty years after its release, the black oat cultivar IAPAR 61 presents the best resultsfor forage production and soil coverage in the Southern region. However, the successiveuse of the grain as seed by the producer can cause natural variability due to mechanical mixing, natural hybridization and mutation. In view of the great importance of this cultivar in the market, the interest of producers and researchers has been aroused to launcha new cultivar derived from its genotype, which maintains the phenotype of the main characteristics, enhancing its forage use and valuing a good seed production. Consideringthe above, the selection of inbred lines within the IAPAR 61 cultivar may provide the launch of an improved black oat cultivar. Thus, the main objective of this work was to perform a cycle ofselection ofinbred lines within the cultivar IAPAR 61, aiming to obtaina new cultivar to replace the existing one with advantage and at the same time obtain estimates of genetic and phenotypic parameters that can assist in the selection, seeking the identification and exploitation of genetic variability through the estimation of geneticparameters. The work was conducted at the IDR-Paraná Research Hub, in Ponta Grossa (PR), during the 2021 harvest. We evaluated 209 lines of black oats from the cultivar IAPAR 61. The characters analyzed were: performance, resistance to leaf rust and leaf spot, frost tolerance, total green dough, percentage of dry dough, plant height, panicle mass, number of grains per panicle, mass of one thousand grains, and panicle weight. Phenotypic data were subjected to univariate analysis of variance (p ≤ 0.01) and genetic parameters were estimated using the mathematical expectation of mean squares. The estimates of the variance component between strains were significant showing that thereis a difference between the pure lines. The estimates of phenotypic variance among line means (σ̂ 2 F), environmental variance (σ̂ 2 e),

genetic variance (σ̂

2G), heritability (h 2 ), coefficient of genetic variation (CVG), coefficient of environmental variation (CVe), ratio between genetic and environmental coefficients of variation, quotient b̂ (CVG/CVe) and accuracy (rgg') indicated a very favorable situation for selection for all traits analyzed inthe 209 black oat lines. Given these results it was possible to verify that there is genetic variability in the heterogeneous black oat cultivar IAPAR 61, enabling the selection of 100 pure lines based on the values obtained for heritability, for continuity in the selectionprocess. The selected pure lines associate good seed production, high forage and soil coverage potential and resistance to leaf rust and leaf spot.