Preliminary operational genetic management units of a highly fragmented forest tree species of southern South America

Pastorino, Mario J.; Gallo, Leonardo

doi:10.1016/j.foreco.2009.03.030

Cited by 21 publications

(40 citation statements)

References 18 publications

(18 reference statements)

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“…This supports the idea of an isolation ("isolation by wind", Gallo and Pastorino, 2010) and genetic drift effect on the considered traits in these small populations. In fact, our findings confirm previous reports in other quantitative traits (Aparicio et al, 2010;Pastorino et al, 2010) and also in neutral markers (Pastorino and Gallo, 2009;Arana et al, 2010).…”

Section: Discussionsupporting

confidence: 92%

“…Trees are 4 to 6 m tall, tortuous, centenary, and scattered around the tops of two rocky hills, over an area of about 4 ha each. Previous studies with neutral markers (isozymes: Pastorino and Gallo, 2009; and microsatellites: Arana et al, 2010) have shown that in spite of their physical closeness, they are genetically very distant, which has been interpreted as evidence of genetic drift and isolation.…”

Section: Samplingmentioning

confidence: 99%

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Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

et al. 2012

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Water-use efficiency (WUE) is a physiological parameter that plays a significant role in the evolutionary dynamics of many forest tree species. It can be estimated indirectly through carbon isotope discrimination (Δ). In general, plants of more arid origins have lower values of Δ. In order to study the degree of genetic control of this parameter and the genetic variation in Δ of Patagonian Cypress seedlings, three Argentinean natural populations chosen to represent two contrasting precipitation regimes were sampled in a common garden trial. The dry situation was represented by two neighboring marginal forest patches from the steppe, while the humid condition was represented by a population with 1,200 mm higher mean annual precipitation. Height (H) and Δ were measured in 246 five-year-old seedlings from 41 open-pollinated families. The factor 'family' had a significant effect on both variables; however heritability for Δ was found not to be significant in two out of the three populations. This could be explained by low sample size in one of them and by a real evolutionary effect in the other. An inverse association between H and Δ was verified, which is interpreted as evidence of an adaptation process at the intra-population level. The studied populations were not shown to discriminate carbon isotopes differently; hence evidence of adaptation to current environmental conditions could not be obtained. On the other hand, the arid populations proved to be quite different in terms of genetic variation, which seems to be the consequence of genetic drift and isolation.Key words: Austrocedrus chilensis; differentiation; adaptation; genetic drift. ResumenVariación genética de poblaciones naturales de Ciprés de la Cordillera con regímenes de precipitación contrastados, en la eficiencia del uso del agua de plántulas, a través de la discriminación isotópica del carbono La eficiencia en el uso del agua es un parámetro fisiológico que desempeña un rol significativo en la dinámica evolutiva de muchas especies forestales. Puede estimarse indirectamente a través de la discriminación isotópica del carbono (Δ). En general, las plantas de orígenes más áridos tienen valores de Δ más bajos. Con el propósito de estudiar el grado de control genético de Δ y la variación genética en este parámetro en plántulas de Ciprés de la Cordillera, tres poblaciones naturales elegidas para representar dos regímenes de precipitación contrastados fueron muestreadas en un ensayo de ambiente común. La condición árida estuvo representada por dos fragmentos de bosque esteparios marginales, vecinos entre sí, mientras que la condición húmeda fue representada por una población con una precipitación media anual 1.200 mm superior a la de las áridas. Se midió altura total (H) y Δ en 246 plántulas de 5 años de edad correspondientes a 41 familias de polinización abierta. El factor 'familia' tuvo un efecto significativo en ambas variables; sin embargo, la heredabilidad para Δ no resultó significativa en dos de las tres poblaciones. En una de ellas esto pod...

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Section: Discussionsupporting

confidence: 92%

Section: Samplingmentioning

confidence: 99%

Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

et al. 2012

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“…Previous research has failed to identify a consistent pattern of genetic variation in Austrocedrus . Little genetic structure was documented in a previous study employing isozymes ( F ST = 0.060) (Pastorino & Gallo 2009). Although, relatively high phenotypic plasticity was suggested for morphological traits (Gyenge et al 2005; Pastorino et al 2010), and genetically controlled differences driven by temperature were found in cuticular lipids (Dodd & Afzal‐Rafii 2000).…”

Section: Introductionmentioning

confidence: 88%

Genetic Diversity and Structure in Austrocedrus chilensis Populations: Implications for Dryland Forest Restoration

Souto

Heinemann

Kitzberger

et al. 2011

Restoration Ecology

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In South America, 94% of dry-temperate lands present some degree of environmental degradation, highlighting the need for ecological restoration. We analyzed geographic patterns of genetic variation in Austrocedrus chilensis, a dominant conifer of the steppe-forest ecotone in the eastern Andes, to examine its potential for restoration. We sampled 67 locations in Argentina and estimated genetic parameters to determine the effects of historical factors affecting diversity, together with inbreeding and gene flow, using 12 allozyme loci. Genetic diversity decreased southwards in eastern populations, which are marginal for the range of the species and patchily distributed, while high genetic admixture was detected in continuous western populations, possibly reflecting postglacial migrations from northern and eastern sources. Higher inbreeding (F IS > 0.14) was recorded in northern compared with southern populations, attributed to the impact of recent bottlenecks resulting from anthropogenic fires. Gene flow was found to be moderate overall (F ST = 0.12). The implications of these results for restoration actions focusing on Austrocedrus were explored. Relatively small, inbred yet genetically diverse northern populations should be the subject of passive restoration efforts, while experimental common gardens should be established toward the south, to support active restoration approaches. This illustrates how ahead of time information on patterns of genetic variation can support restoration efforts for dryland tree species.

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“…Souto et al () revealed eight enzymes, whereas Pastorino and Gallo () revealed just seven, of which five were coincident. One of the non‐coinciding enzymes in the set utilized by Souto et al () is cathodal peroxidase (Per Cat E.C.1.11.1.7).…”

Section: The Toolmentioning

confidence: 99%

“…et Bizzarri natural populations in Argentina. However, a previous genetic diversity study also based on isozymes and also including structure analysis (Pastorino & Gallo , ) concluded that at least five seed transfer zones are necessary. These controversial conclusions warrant discussion, which unfortunately was absent from the more recent article.…”

Section: Introductionmentioning

confidence: 99%

How Many Seed Transfer Zones Are Necessary for the Preservation of the Genetic Identity of Austrocedrus chilensis Natural Populations in Argentina?

Pastorino

2012

Restoration Ecology

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Two different studies based on isozymes that include genetic structure analysis have arrived at contrasting conclusions regarding the minimum number of seed transfer zones for Patagonian cypress (Austrocedrus chilensis) in Argentina that are required in order to avoid genetic contamination in restoration programs. Unfortunately, the more recent article lacks discussion on these controversial results, which is, therefore, the purpose of this article. The reliability of the markers used and the sampling performed in these studies are evaluated comparatively. The later study found higher levels of diversity and differentiation but paradoxically suggested that only two seed transfer zones would be enough to preserve the genetic identity of the natural populations of the species, whereas the earlier study concluded that at least five are necessary. Arguments are presented here for the case that definition of fewer than five genetically homogeneous groups is absolutely inappropriate and implies a probable risk of genetic contamination and maladaptation.

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Preliminary operational genetic management units of a highly fragmented forest tree species of southern South America

Cited by 21 publications

References 18 publications

Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

Genetic variation in seedling water-use efficiency of Patagonian Cypress populations from contrasting precipitation regimes assessed through carbon isotope discrimination

Genetic Diversity and Structure in Austrocedrus chilensis Populations: Implications for Dryland Forest Restoration

How Many Seed Transfer Zones Are Necessary for the Preservation of the Genetic Identity of Austrocedrus chilensis Natural Populations in Argentina?

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