Several studies have expressed concerns about the effects of gene flow from transgenic herbicide‐resistant crops to their wild relatives, but no major problems have been observed. This review describes a case study in which what has been feared in transgenics regarding gene flow has actually changed biodiversity and people's lives. Nontransgenic imidazolinone‐resistant rice (IMI‐rice) cultivars increased the rice grain yield by 50% in southern Brazil. This increase was beneficial for life quality of the farmers and also improved the regional economy. However, weedy rice resistant to imidazolinone herbicides started to evolve three years after the first use of IMI‐rice cultivars. Population genetic studies indicate that the herbicide‐resistant weedy rice was mainly originated from gene flow from resistant cultivars and distributed by seed migration. The problems related with herbicide‐resistant weedy rice increased the production costs of rice that forced farmers to sell or rent their land. Gene flow from cultivated rice to weedy rice has proven to be a large agricultural, economic, and social constraint in the use of herbicide‐resistant technologies in rice. This problem must be taken into account for the development of new transgenic or nontransgenic rice technologies.

Resumo -O objetivo deste trabalho foi avaliar a eficiência bioeconômica de cordeiros F 1 Dorper x Santa Inês para produção de carne. Analisou-se o desempenho de ovinos ½ sangue Dorper x ½ sangue Santa Inês, nas fases de cria e de acabamento. A fase de produção das crias foi realizada em caatinga nativa e a fase de acabamento em confinamento. As matrizes foram suplementadas nos últimos 50 dias de prenhez e nos primeiros 30 dias de lactação. As crias foram desmamadas aos 70 dias de idade, divididas em três lotes e confinadas, alimentadas com capim-elefante (Pennisetum purpureum) ad libitum e concentrado na proporção de 1,5%, 2,5% e 3,5% do peso vivo, respectivamente. O sexo não exerceu influência sobre os pesos no nascimento, no desmame, nem sobre o ganho em peso até o desmame. Não foi observada influência do sexo sobre os pesos e os ganhos em peso aos 30 e 50 dias de confinamento. Nas fases de produção e acabamento em confinamento, os animais de nascimento simples foram superiores aos de nascimento duplo quanto a essas variáveis. Houve efeito linear significativo para peso e ganho em peso aos 30 e 50 dias de confinamento. Os três níveis de uso de concentrado foram economicamente viáveis. As margens brutas de peso vivo, por kg de cordeiro produzido, foram de R$ 0,26 kg -1 , R$ 0,30 kg -1 e R$ 0,36 kg -1 para concentrados a 1,5%, 2,5% e 3,5% do peso vivo, respectivamente. Os melhores resultados econômicos foram obtidos quando o nível de concentrado foi de 3,5% do peso vivo.Termos para indexação: ovino, cruzamento industrial, peso corporal, ganho em peso, confinamento, viabilidade econômica. Bioeconomic efficiency of F 1 Dorper x Santa Inês lambs for meet productionAbstract -The objective of this work was to evaluate bioeconomic efficiency of F 1 Dorper x Santa Inês lambs for meet production. Performance of F 1 Dorper x Santa Inês lambs in raising and fattening phases was analyzed. The production phase of lambs was realized in native pastures ("caatinga") and the finishing phase was in confinement. The ewes were supplemented during the last 50 days of pregnancy and the first 30 days of lactation. Lambs were weaned at 70 days of age, divided into three lots, confined and fed elephant grass (Pennisetum purpureum) ad libitum, and concentrate in the proportion of 1.5%, 2.5% and 3.5% of live weight, respectively. Lambs sex did not have significant influence on birth weight, as well as on weaning weight and weight gain until weaning. In production and confinement phases, lambs of single births were superior to double births ones considering these variables. Linear effect was significant for weight and for weight gain, at 30 and 50 days of confinement. The three inclusion levels of concentrate were economically viable. Gross margins of live weight for each kg of lamb produced were R$ 0.26 kg -1 , R$ 0.30 kg -1 and R$ 0.36 kg -1 of live weight to concentrates of 1.5%, 2.5% and 3.5%, respectively. The best economics results were obtained when the concentrate level was 3.5% of live weight.

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The gains in non-agricultural activities represents a new dynamic in rural Brazil and now has representation in Brazil from the 1990s. In this perspective, the Brazilian countryside is undergoing a reconfiguration, pointing to an intensification of the urbanization of rural areas, especially in peri-urban areas. The installation of industries in rural areas, the deployment of agribusinesses and food exporters and utilization of rural labor for those industries, are tying the stretches between urban and rural areas. Thus, rural households are increasing income through agricultural and non-agricultural activities. The rural environment is no longer exclusively agricultural. It went on to have a diversified productive base and integrated economy in the region. Since there is a growing rural human being mobility, as well as an improvement in communication and access to information and greater integration between markets reducing the dichotomy between urban and rural. On the other hand the expansion of the cultivation of sugar cane on a region can increase the (Gross National Product) GNP per capita of the region and enable an increase economical activity. Thus, the rural household pluri-activity can be an alternative to increase the income of these families as they, increasingly integrate with the local market. It is known that with rising incomes and improving the welfare of the rural population can reduce the rural exodus that became increasing in the country since the 1970s. However, in areas with predominantly or expansion of monoculture, as an example of cane sugar, may be an increased land concentration and a worsening of income distribution in a region, and to record an increasing in rural migration, Environmental degradation and reduced local production diversification. An analysis of several indicators, socio-economic and environmental, through the Dashboard of Sustainability is possible to tell which category has the highest rate of farmer sustainability, whether smallholders or monoculture. However, the secondary data available in Brazil today does not support a thorough analysis of the participation of each actor and to which the interconnection between the actors and their synergy in local economic activity. Since, given the narrowing between urban and rural, the statistical data available are not able to demonstrate the extent to which gives the rural-urban dichotomy. Thus, it is relevant to point out and discuss ways to provide consistent statistical data and be, in fact, able to demonstrate the local reality of a region within the welfare actors.