GENETIC VARIATION IN WILD AND AGRICULTURAL POPULATIONS: GENETIC CONSERVATION

1998 ◽  
Vol 55 (3) ◽  
pp. 329-341 ◽  
Author(s):  
T. R. Allnutt ◽  
P. Thomas ◽  
A. C. Newton ◽  
M. F. Gardner

Fitzroya cupressoides (Molina) Johnston (Cupressaceae), a threatened conifer native to southern South America, has been cultivated in a number of gardens and arboreta in the British Isles since its introduction in 1849. In order to assess the importance of these cultivated trees for ex situ conservation, foliar samples were collected from 48 trees from throughout the British Isles, including five of known wild origin (Chile). DNA was extracted from these samples and assessed using the RAPD technique, in order to examine the extent of genetic variation. All samples from the cultivated trees of unknown origin, with one exception, were found to be genetically identical. In contrast, the five samples of known wild origin revealed pronounced polymorphism, varying from 5.3% to 49.1% between individuals. These results suggest that virtually all of the F. cupressoides trees currently cultivated in the British Isles have been derived from a single individual by vegetative propagation. Their value for ex situ conservation is therefore likely to be extremely limited. The implications of these results for the genetic conservation of other taxa in gardens and arboreta is discussed.


2019 ◽  
Vol 68 (1) ◽  
pp. 73-78 ◽  
Author(s):  
B.I. Aguiar ◽  
M.L.M. Freitas ◽  
Y.R. Tavares ◽  
E.V. Tambarussi ◽  
B. Zanatto ◽  
...  

Abstract The Atlantic Forest has very high levels of biodiversity and is considered one of the most important and threatened biomes in the world. Balfourodendron riedelianum is one of the forest’s characteristic tree species that is currently under considered endangered due to timber extraction and forest fragmentation. With the goal of generating information that may contribute to the genetic conservation of B. riedelianum, genetic parameters are estimated for quantitative traits important for silviculture in a provenance and progeny test located in the Experimental Station of Luiz Antônio, São Paulo State, Brazil. The test was established in 1986 and consists of three provenances, from which open-pollinated seeds from 19 seed trees were collected. The following traits were evaluated at 32 years of age: diameter at breast height (DBH), total height (H), stem height (SH), stem straightness (SS), and forking (FOR). The estimates were carried out using the REML/BLUP method. Significant genetic variation among progenies was detected for all traits (except SH) and between provenances for DBH. The coefficient of individual genetic variation (CVgi) ranged from 2.5 to 9.5 %. The mean heritability among progeny ( $h_f^2$ ) was substantial for DBH (0.44) and FOR (0.36), enabling the selection of families with the highest DBH and lowest FOR for population improvement. Genotypic and phenotypic correlations among traits were also found. We conclude that there is genetic variability in the population that can be exploited in future breeding programs and for the genetic conservation of the species.


2011 ◽  
Vol 49 (01) ◽  
Author(s):  
A Tönjes ◽  
A Tönjes ◽  
T Strauch ◽  
C Ruffert ◽  
J Mössner ◽  
...  

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