Avaliação do ganho genético de mutantes-sem m4 em Urochloa brizantha cultivar Marandu

Abstract

Currently, pastures are of great importance, as cattle herds are raised almost exclusively on pasture. For a more competitive livestock and less impacting the environment, it is necessary to use superior cultivars, which offer better productivity and quality. The improvement of forages of the genus Urochloa is extremely complex since these plants basically perform asexual reproduction by agamospermy, making it difficult to obtain new variations to be selected. A viable alternative is the induction of mutations, which can produce variants of a material in cultivation with real gains in some characteristics, such as productivity, architecture and nutritional contents; however it is still a very recent activity. The objective of this work was the morphological characterization of five accessions of mutants of Urochloa brizantha cv. Marandu and evaluations to assess the genetic gain obtained by the mutation process in relation to the original cultivar. Growth characteristics, production of fresh and dry matter and nutritional contents in summer and winter were evaluated. At the end, the genetic gain of these materials was evaluated in relation to the original material, the cultivar Marandú. The following evaluations were carried out: Fresh Matter, Number of tillers; Tiller length; Total dry matter (MSTot); Nutritional assessments and estimated productivity of fresh and dry matter (PEMF and PEMS). The evaluations were carried out at UNOESTE's experimental campus II. The experiment was designed in completely randomized blocks, in a combination of five materials each with 3 replications. The results found were genetic gains in number of tillers of 4.41% in material F3 and for the characteristic of plant height, material 19C showed the highest gain of 3.11%. We can say that the 19C, F3 and 10M2 materials stood out from the other materials, where the 10M2 material, even with similar characteristics to the witness, stands out mainly in its ground cover and in its resistance to low temperatures, it is also noticed that the 19C material presents a genetic gain in plant height and F3 a genetic gain in tiller production, and all had the highest results in fresh mass gain.