Caracterização e identificação de acessos locais de Avena strigosa da Região Norte do Rio Grande do Sul

Abstract

Local populations of black oats (Avena strigosa Schreb.) are important genetic resources for plant breeding programs which aim to obtain genitors with superior characteristics. The aim of this paper was to characterize a set of 46 local accesses of black oat of undefined origin ( landrace), using morphological and agronomic descriptors.The germplasm was obtained by seeds, in agricultural properties and rural settlements of Rio Grande do Sul state, and next to the Laboratório de Análises de Sementes of the University of Passo Fundo. The experiments occurred in 2017 and 2018, in the field and laboratory. In 2017, the experiment consisted of 46 accesses, established in a randomized complete block design, with three replicates. In this year, the plants were characterized as 26 official descriptors of Avena spp., with addition of 14 morphological and agronomic characters. In 2018 the twenty accesses that, in the previous experiment, showed superiority in yield and weight of 1000 grains, biomass production, number of tillers, stature, cycle and vegetative habit. The experiment consisted of 22 treatments, including the accesses and two cultivars (UPFA 21 Moreninha; IPR Cabocla), which served as witnesses. The experimental design was in randomized blocks, with three replications. The accesses were evaluated for the production and nutritional value of the biomass as well as associated characters. Data were submitted to analysis of variance and, where appropriate, the means were compared by the Skott Knott test at 5% significance. Multivariate analysis was performed to access germplasm dissimilarity, with the use of cluster analysis and dendrograms generation.The accesses presented variation regarding the vegetative habit, flag leaf position, awn type and frequency of plants with curved flag leaf, lengths of floral and glume axis, height and cycle of the plant. Total number of tillers, length of the first internode of main culm and lemma length were the most important characters in the divergence between the accesses. The accesses P2017-48-1-2, P2017-2-1-2 and P2017-47-1-2 are materials which deserve to be evaluated, in continuity to what has been tested in this paper, for the potential in biomass production to cover the ground, forage production and genetic dissimilarity. The seed samples from the accesses are tipped next to the UPF Oat Breeding Program and together with the dissimilarity matrices generated in the two phases of the study represent a possibility of use for black oats plant breeding programs in order to generate variability and to potentiate the black oat cultivars development.