Morphological, isoenzimatic and molecular characterization of rice cultivars / CaracterizaÃÃo morfolÃgica, isoenzimÃtica e molecular de cultivares de arroz




Morphological, isoenzimatic and molecular markers were used to characterize commercial rice cultivars. The morphological characterization consisted in two experiments, the first one was done in green house, at Federal University of Lavras, when the cultivars were characterized using the descriptors recommended for the protection cultivar law in Brazil. The second experiment was in a seed production field, in EPAMIG, Lavras. In this experiment, contaminants rice seeds were identified for researchers among studied cultivars. In the isoenzimatic characterization, was analyzed isoenzimes from seeds and tissue of rice plantlets, using horizontal gel electrophoresis. This part of the research was done in Embrapa-cpact, Pelotas, RS. The isoenzimatic systems analyzed were esterase, 6-fosfogluconate dehydrogenase, isocitrate desydrogenase and leucine aminopeptidase. For the similarity analysis was used the Jaccard coefficient. The molecular analyses of microsatellites had the objective to identify microsatellites in or around rice genes, to develop primers to the microsatellites selected and to characterize the rice cultivars using the primers developed. Thirteen microsatellites were selected in upstream region of Mads Box genes and 37 microsatellites in ESTs (Expressed Sequence Tags). To search and to select microsatellites were used the databases from rice genome sequencing and used bioinformatics tools available at Plant Research International, Holland, where this research was developed. To analyze the microsatellites was used polyacrilamide gel 6% and the gel was submitted to silver staining. The similarity analysis was done the same way of isoenzyme analysis. The PIC (Polymorphic Informative Content) of microsatellites markers was among 0,05 and 0,955. The conclusions were that the morphological descriptors were useful, but not enough to characterization and discrimination of rice cultivars, the morphological characteristics observed after the reproductive phase are the more suitable to characterization and discrimination of rice cultivars. Isoenzimatic markers allow to characterize rice cultivars and are capable to differentiate all upland rice cultivars studied, excluded Carisma, IAC 202 and Guarani. The esterase isoenzymes are influenced for the presence of fungus in the seeds and the isoenzymes of 6- fosfogluconate dehydrogenase can be altered according to physiologica quality of the seeds. The microsatellites analyzed allows conclude that is possible to find microsatellites in or around rice genes. The analysis of the microsatellites studied allows separate the cultivars according the subspecies, indica or japonica.


arroz marcador morfologico morphological characterization rice pureza genÃtica genetic pureness fitotecnia

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