Variabilidade genética e fluxo gênico em populações híbridas e silvestres de pupunha acessada com marcadores RAPD

As populações híbridas de pupunha (Bactris gasipaes Kunth) acumularam variabilidade genética provenientes de raças primitivas ao seu redor, o que deveria aumentar sua variabilidade. Para testar esta hipótese, avaliou-se a variabilidade genética de populações híbridas por meio de marcadores RAPD utilizando 176 plantas mantidas no Banco Ativo de Germoplasma do INPA, Manaus-AM, sendo quatro populações híbridas [Belém (n=26); Manaus (n=38); Iquitos, Peru (n=41); Yurimáguas, Peru (n=41)], duas populações silvestres (B. gasipaes variedade chichagui) tipos 1 (n=21) e 3 (n=7), e duas amostras de espécie afim, B. riparia, e compararam-se os parâmetros genéticos com estudos das raças primitivas. Oito iniciadores RAPD geraram 88 marcadores polimórficos e 11 monomórficos. O teste de replicabilidade apresentou uma similaridade de Dice 0,67, considerado aceitável. A heterozigosidade média das populações híbridas foi 0,34 e o polimorfismo foi 87,9%, maiores que nas silvestres (0,31; 74,7%). O dendrograma das similaridades de Dice não apresentou grupos que representassem claramente as populações híbridas. O fluxo gênico entre Iquitos e Yurimáguas (Nm=12,75) e entre Iquitos e Manaus (Nm=9,47) foi alto, enquanto o fluxo entre Belém e Manaus (Nm=7,72) foi menor que o esperado, possivelmente devido à influência da raça Solimões. O alto valor de heterozigosidade em Manaus (0,31) parece ser resultado da união de duas dispersões após a domesticação: a do oeste amazônico, com Iquitos e Yurimáguas, e a do leste amazônico, com Belém, que se juntam em Manaus. No entanto, essas populações não apresentaram acúmulo de variabilidade genética tão expressiva para diferenciá-las das raças primitivas

Padrão geográfico de diversidade genética em populações naturais de Pau-rosa (Aniba rosaeodora), na Amazônia Central

Rosewood (Aniba rosaeodora Ducke, Lauraceae) is an Amazonian evergreen tree and a source of the purest linalool, the main component of its essential oil, which is very valuable in the international perfumery market. After decades of over-exploitation it is currently considered as threatened. We evaluated the genetic diversity and its distribution in four populations in Central Amazonia. Thirty-five reliable RAPD markers were generated, of which 32 were polymorphic (91.4%). Variation was higher within the populations (76.5%; p < 0.0001) and geographic distribution contributed to population differentiation (23.4%; p < 0.0001). The Amazon River had a small influence on gene flow (3.3%; p < 0.0001), but we identified evidence of gene flow across the river. There were significant differences in marker frequencies (p < 0.05), in agreement with the low gene flow (Nm = 2.02). The correlation between genetic distance and gene flow was - 0.95 (p = 0.06) and between geographic distance and gene flow was -0.78 (p = 0.12). There was a geographic cline of variability across an East-West axis, influenced as well by the Amazon River, suggesting the river could be a barrier to gene flow. Although threatened, these Rosewood populations retain high diversity, with the highest levels in the Manaus population, which has been protected for over 42 years in a Reserve.O Pau-rosa (Aniba rosaeodora Ducke, Lauraceae) é uma árvore amazônica fonte do mais puro linalol, o qual é o principal componente do seu óleo essencial e muito valioso no mercado internacional de perfumaria. Após várias décadas de intensa exploração, a espécie foi levada à categoria de ameaçada de extinção. Quatro populações naturais distribuídas na bacia Amazônia Central foram avaliadas quanto ao nível e a distribuição da diversidade genética. Trinta e cinco marcadores RAPD reprodutíveis foram gerados, dos quais 32 foram polimórficos (91,4%). A diversidade foi maior dentro das populações (76,5%; p < 0,0001) e a distribuição geográfica contribuiu para a diferenciação entre as populações (23,4%; p < 0,0001). A AMOVA indicou que pode haver uma influência parcial do Rio Amazonas no fluxo gênico (3,3%; p < 0,0001), mas foram identificadas evidências de fluxo gênico atravessando o rio. Houve diferenças significativas nas freqüências dos marcadores (p < 0,05) e o fluxo gênico estimado foi relativamente baixo (Nm = 2,02). A correlação entre a distância genética e o fluxo gênico foi de - 0,95 (p = 0,06) e para a distância geográfica e o fluxo gênico foi de - 0,78 (p = 0,12). Houve um padrão geográfico de variabilidade ao longo do eixo Leste - Oeste, influenciado também pelo Rio Amazonas, o que sugere que o rio poderia funcionar como uma barreira para o fluxo gênico. Apesar de ameaçadas, estas populações de Pau-rosa possuem alta diversidade, com o maior valor na população de Manaus, que vem sendo protegida por 42 anos em uma reserva

Testing criteria and indicators for assessing the sustainability of forest management : genetic criteria and indicators

This working paper contains proposals for specific genetic criteria and indicators (C and I) which are expected to be part of a more general set of biological C and I These proposals are intended for use in guiding tropical forest management but the indicators and verifiers we describe are not in theform of simple prescriptions where a single measurement can be recommended for a single causal effect. Since genetic dynamics operate at a different time and spatial scale than the events that can be observed at the level of forest stand effects, a single forest stand event can have effects on several genetic processes. In addition, the pattern of genetic diversity that has already evolved is due to a balance of several evolutionary forces that operate at different spatial and temporal scales and forest practices would therefore be expected to affect several genetic factors. To provide guidance on what genetic processes may be affected by forest practices, we therefore first describe the factors that affect genetic processes and then provide a matrix of relationships between types of forest level events and genetically significant factors. Since the intention of the larger project is to steer possible management actions, the report identifies two main concerns of sustainability : first, whether the genetic variation is being maintained, and second, what conservation or enhancement measures can be effective. We state one criterion and for each of these concerns, sets of indicators are defined that would address the issue of sustainability. For each indicator, sets of verifiers are provided which differ in the biologically relevant feature they measure or in the precision and technical facilities they require. Finally, the need for rapid assessment and precision under difficult field conditions requires research and development of efficient direct and surrogate measures of the genetic resource. We therefore include recommendations for shortand medium term research that would improve the scientific value, costeffectiveness, ease of use, and further development of genetic criteria and indicators

Testing Criteria and Indicators for assessing the sustainability of forest management: genetic criteria and indicators

This working paper contains proposals for specific genetic criteria and indicators (C&I) which are expected to be part of a more general set of biological C&I. These proposals are intended for use in guiding tropical forest management but the indicators and verifiers we describe are not in the form of simple prescriptions where a single measurement can be recommended for a single causal effect. Since genetic dynamics operate at a different time and spatial scale than the events that can be observed at the level of forest stand effects, a single forest stand event can have effects on several genetic processes. In addition, the pattern of genetic diversity that has already evolved is due to a balance of several evolutionary forces that operate at different spatial and temporal scales and forest practices would therefore be expected to affect several genetic factors. To provide guidance on what genetic processes may be affected by forest practices, we therefore first describe the factors that affect genetic processes and then provide a matrix of relationships between types of forest level events and genetically significant factors. Since the intention of the larger project is to steer possible management actions, the report identifies two main concerns of sustainability: first, whether the genetic variation is being maintained, and second, what conservation or enhancement measures can be effective. We state one criterion and for each of these concerns, sets of indicators are defined that would address the issue of sustainability. For each indicator, sets of verifiers are provided which differ in the biologically relevant feature they measure or in the precision and technical facilities they require. Finally, the need for rapid assessment and precision under difficult field conditions requires research and development of efficient direct and surrogate measures of the genetic resource. We therefore include recommendations for short- and medium term research that would improve the scientific value, cost-effectiveness, ease of use, and further development of genetic criteria and indicators

Criteria and indicators for sustainability forest management: assessment and monitoring of genetic variation

The paper contains proposals for genetic criteria and indicators wich can form part of a more general set of, economic, environmental and social criteria and indicators for the monitoring of forest sustainability at the scale of forest management units. It proposes one criterion for conservation of forest genetic resources and four indicators related to processes that maintain genetic diversity. For each indicator, sets of verifiers are suggested which differ in the biologically relevant features they measure, in their precision, and in technical facilities they require. Finally, the need for rapid assessment and precision under difficult conditions requires research and development of efficient direct surrogate measures of the genetic resource. We therefore include recommendations for short- and medium term research that would improve the scientific value, cost effectiveness, ease of use, and further development of genetic criteria and indicators

Level and transmission of genetic heterozygosity in apricot (Prunus armeniaca L.) Explored using simple sequence repeat markers

8 pages, 1 figure, 3 tables.-- Published online: 24 June 2005.In this study, 17 peach simple sequence repeat (SSR) sequences were used in the exploration of the genetic heterozygosity level of several apricot cultivars from Spain, France, Greece, and the USA, and 23 descendants. The genotypes can be classified in three groups as a function of their genetic heterozygosity (1) local cultivars from Murcia (Spain) (‘Gitanos’ and ‘Pepito del Rubio’) and several descendants from crosses among these cultivars, with very low genetic heterozygosities (less than 0.30); (2) cultivars from France and Spain (‘Moniquí’, ‘Currot’ and ‘Bergeron’) and several descendants, with intermediate levels of genetic heterozygosity (around 0.45); and (3) cultivars ‘Orange Red’ and ‘Goldrich’ from North America and ‘Lito’ from Greece, with the remaining descendants, having genetic heterozygosities higher than 0.50. The results showed the high increase of genetic heterozygosity in the case of descendants from complementary crosses. The use of cultivars from North America could increase greatly the genetic heterozygosity in the Spanish apricot breeding programs, enlarging the genetic variability of the local cultivars. On the other hand, in the case of transgressive crosses among local Spanish cultivars, the increase of genetic heterozygosity was much lower.This work has been financed by the project AGL2001-112-C02-01 from the Spanish Ministry of Science and Technology. The authors also acknowledge the support of the Spanish Ministry of Science and Technology for the contract of Dr P. Martínez-Gómez.Peer reviewe