Navegando por Autor "Flôr, Mateus Ferraz"

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Avaliação do indice de germinação em diferentes genótipos de cana-de-açucar
(2018-08) Flôr, Mateus Ferraz; Silva, Gheysa Coelho; http://lattes.cnpq.br/5485750178709039
The Simplified Selection System (SSS) has the objective of reducing the time for releasing a new variety. However, it presents limitations as to the composition of base populations for selection of families, which must contain the same number of seedlings. The objective of this work was to compare and evaluate the germination index of caryopses obtained by means of different crossing methods and to determine the quantitative of seeds to be used to compose the base population for selection among families by the SSS method. The experiment was conducted under a completely randomized design. Caryopses of 27 crosses between energy cane breeders were evaluated, being eight biparental, ten polycrossing and nine self-fertilization. Sowing of four 0.5 gram samples of caryopses was done by crossing. The number of caryopses germinated five and thirty days after sowing was evaluated. The general averages were grouped by the Scott-Knott method and the comparison between the averages of the different crossing methodologies were performed by the Tukey’s test at 5% of probability. It was verified that the C27 crossing presented the highest germination average of the caryopse in the first evaluation. At the second evaluation, the crosses C8 (76.74%), C27 (61.02%), C3 (53.99%) and C13 (49.65%), although they were statistically different, were shown with high averages. It was observed that, in the first evaluation, the caryopses obtained through self-fertilization presented the highest germination average (12.82%), followed by the polycrosses (10.88%) and the biparental crosses (9.99%), while in the second evaluation, the highest percentage of germination was verified in the biparental crosses (31.10%), followed by the self-fertilization (21.35%) and polycrosses (20.43%). It was verified that the majority of the evaluated crosses presented low germination, being necessary of 2.71 to 800 grams of seeds to homogenize the number of individuals by family. Therefore, it was concluded that only crosses with high germination are recommended to compose the families that will be evaluated through the SSS. Caryopses obtained through self-fertilization germinate rapidly in comparison to the other methods, once that biparental crosses between selected energy cane parents tend to present higher fertility of caryopses. Families C1, C3, C8, C13, C26 and C27 can be used to compose the base populations in the simplified selection system.