Universidade Federal de Viçosa

About: Universidade Federal de Viçosa is a education organization based out in Viçosa, Brazil. It is known for research contribution in the topics: Population & Biology. The organization has 16012 authors who have published 26711 publications receiving 353416 citations.

Genetic variability and heterotic groups of Brazilian popcorn populations

Abstract: The development of successful advanced lines and cultivars in maize is dependent on parental selection and assignment to defined heterotic groups So, the objectives of this study were to evaluate genetic variability and identify heterotic groups among Brazilian popcorn varieties Thus, diallel crosses of advanced generations of the popcorn hybrids, IAC 112 and Zelia, and of three open-pollinated popcorn varieties, RS 20, Branco, and SAM were performed Ten hybrid combinations, the five parents, and five check treatments were arranged in a block design with four replicates in two tropical-zone locations (CWb climate) Both additive and non-additive effects were important for grain yield, plant height, ear height, and husk cover For popping expansion, only the additive effects were important Hybrid combinations between the local variety (Branco) and F2 populations (IAC 112 and Zelia) resulted in the third and fourth highest values for popping expansion The best grain yields were obtained with hybrid combinations involving SAM Cultivars Zelia, IAC 112, and RS 20 increased popping expansion, whereas cultivar Branco increased grain yield of hybrid combinations The following conclusions may be drawn: Brazilian popcorn populations have reduced heterosis and genetic variability to popping expansion in relation commercial cultivars; there is genetic variability among Brazilian popcorn populations that allows the exploitation of additive and non-additive effects for grain yield; it is possible to increase grain yield by using local varieties; but it would be difficult to obtain commercial hybrids from local varieties because they have poor performance for popping expansion

Species diversity, phylogeny and genetic variability of begomovirus populations infecting leguminous weeds in northeastern Brazil

Abstract: A survey of begomoviruses infecting leguminous weeds (family Fabaceae) was carried out in four states of northeastern Brazil. A total of 26 full-length begomovirus components (19 DNA-A and seven DNA-B, with three pairs of cognate A and B components) were amplified using rolling-circle amplification, then cloned and sequenced. Sequence analysis indicated the presence of six species, four of them novel. In phylogenetic analysis five of the viruses clustered with other Brazilian begomoviruses, but one of them (Euphorbia yellow mosaic virus, EuYMV) clustered with viruses from other countries in Central and South America. Evidence of recombination was found among isolates of Macroptilium yellow spot virus (MaYSV). The MaYSV population had a high degree of genetic variability. Macroptilium lathyroides was revealed as a common host for several of these viruses, and could act as a mixing vessel from which recombinant viruses could emerge. The results indicate that leguminous weeds are reservoirs of several begomoviruses in Brazil, and could play a significant role in begomovirus epidemics, both as inoculum sources and as sources of emerging novel viruses.