Assessment of Gene Flow to Wild Relatives and Nutritional Composition of Sugarcane in Brazil.

The commercial release of genetically modified organisms (GMO) requires a prior environmental and human/animal health risk assessment. In Brazil, the National Biotechnology Technical Commission (CTNBio) requires a survey of the area of natural occurrence of wild relatives of the GMO in the Brazilian ecosystems to evaluate the possibility of introgressive hybridization between sexually compatible species. Modern sugarcane cultivars, the focus of this study, derive from a series of hybridization and backcrossing events among Saccharum species. The so-called "Saccharum broad sense" group includes around 40 species from a few genera, including Erianthus, found in various tropical regions, particularly South-Eastern Asia. In Brazil, three native species, originally considered to belong to Erianthus, were reclassified as S. angustifolium (Nees) Trin., S. asperum (Nees) Steud., and S. villosum Steud., based on inflorescence morphology. Thus, we have investigated the potential occurrence of gene flow among the Brazilian Saccharum native species and commercial hybrids as a requisite for GMO commercial release. A comprehensive survey was carried out to map the occurrence of the three native Saccharum species in Brazil, concluding that they are sympatric with sugarcane cultivation only from around 14°S southwards, which precludes most Northeastern sugarcane-producing states from undergoing introgression. Based on phenology, we concluded that the Brazilian Saccharum species are unable to outcross naturally with commercial sugarcane since the overlap between the flowering periods of sugarcane and the native species is limited. A phylogenomic reconstruction based on the full plastid genome sequence showed that the three native Saccharum species are the taxa closest to sugarcane in Brazil, being closer than introduced Erianthus or Miscanthus. A 2-year study on eight nutritional composition traits of the 20 main sugarcane cultivars cultivated in Brazil was carried out in six environments. The minimum and maximum values obtained were, in percent: moisture (62.6-82.5); sucrose (9.65-21.76); crude fiber (8.06-21.03); FDN (7.20-20.68); FDA (4.55-16.90); lipids (0.06-1.59); ash (0.08-2.67); and crude protein (0.18-1.18). Besides a considerable amount of genetic variation and plastic responses, many instances of genotype-by-environment interaction were detected.

Correlação entre floração, frutificação e variáveis ambientais em Solanum lycocarpum. A. St. Hil, Solanaceae / Correlation between flowering, fructification and environmental variables in Solanum lycocarpum A. St.-Hil, Solanaceae

A lobeira (S. lycocarpum) é uma espécie típica e abundante do Cerrado, que ocupa principalmente ambientes antropizados. Possui características interessantes do ponto de vista da biologia reprodutiva, que provavelmente estão favorecendo a ampla ocupação pela espécie. Tendo em vista que a planta floresce e frutifica durante todo o ano, o presente estudo teve por objetivo verificar se existe correlação entre floração, frutificação e variáveis ambientais (temperatura, umidade e precipitação), como suporte para estudos futuros referentes à biologia reprodutiva e ecologia de espécies de plantas do Cerrado. Foi escolhida uma população de lobeira situada no município de Morrinhos, Sul do estado de Goiás, composta de 34 plantas em fase reprodutiva. Todas as plantas foram georreferenciados com um aparelho GPS. Foram feitas observações mensais durante 13 meses (junho de 2005 a julho de 2006) e quantificados flores abertas e frutos produzidos nos intervalos entre observações. Pode-se inferir alta conversão de flores hermafroditas em frutos. Por meio da correlação de Spearman, pode-se constatar correlação positiva entre floração e precipitação e umidade, o mesmo, aparentemente, não ocorre para frutificação.

Solanum lycocarpum (lobeira) is a typical and abundant species of brazilian Cerrado, which occupies mainly surrounding disturbed areas. It has interesting characteristics from the point of view of reproductive biology, that probably are favoring the large occupation of habitats by the species. Based on the fact that the species produces flowers and fruit during all the year, the present study had the purpose to verify the association between flower and fruit production with environmental variables (temperature, relative humidity and precipitation), aiming to support future studies referring to reproductive biology and ecology of plant species from Cerrado biome. A population of S. lycocarpum composed of 34 plants in reproductive phase, situated in Morrinhos, south of the State of Goiás, Brazil, , was evaluated. All the plants were geographically referenced with a GPS receptor. Observations were made monthly during 13 months (June, 2005 to July, 2006) quantifying open flowers and fruits produced in the intervals between the observations. It was possible suggest high conversion of flowers in fruits. The Spearman rank correlation showed positive correlation of flower number with precipitation and relative humidity. Fruit number was not correlated with the environmental variables.

Morphoagronomic genetic diversity in american wild rice species

To characterize the genetic variability among species and populations of South American wild rice, eleven populations of Oryza glumaepatula, seven of O. grandiglumis, four of O. latifolia and one of O. alta, from Brazil and Argentina, were evaluated. A greenhouse experiment was conducted in completely randomized blocks with 23 treatments. Twenty morphoagronomic traits were assessed. Univariate analyses were performed with 16 quantitative traits with the partitioning of populations within species. Significant differences (p<0.001) between species were observed for all the traits as well as among populations within the species. The most variable was O. glumaepatula followed by O. latifolia. Multivariate discriminant canonical and cluster analyses confirmed the separation of the highly diverse O. glumaepatula populations from the tetraploid species, and the high genetic variation among O. latifolia populations. Morphological differences among the three tetraploid species seemed to be enough to ascribe them at least the condition of species in statu nascendi.

Visando caracterizar a diversidade genética entre espécies e populações de arroz selvagem da América do Sul, foram avaliadas 11 populações de Oryza glumaepatula, sete de O. grandiglumis, quatro de O. latifolia e uma população de O. alta, originárias do Brasil e Argentina. Foi conduzido um experimento em casa-de-vegetação em blocos ao acaso com 23 tratamentos. Vinte caracteres agro-morfológicos foram avaliados. Análises univariadas foram realizadas para 16 caracteres quantitativos, desdobrando-se o efeito de populações dentro de espécies. Diferenças significativas (p<0,001) entre espécies foram observadas para todos os caracteres bem como entre populações dentro de espécies. A mais variável foi O. glumaepatula seguida de O. latifolia. Análises de agrupamento e discriminante canônica confirmaram a separação das populações de O. glumaepatula das espécies tetraplóides, e a grande variação genética entre populações de O. latifolia. Diferenças morfológicas entre as três espécies tetraplóides parecem suficientes para classificá-las como espécies pelo menos na condição statu nascendi.