Partitioning and distribution of RAPD variation in a forest tree species, Eucalyptus globulus (Myrtaceae)

Abstract

Eucalyptus globulus is an important species for pulpwood production in many countries. The pattern and partitioning of variation is important baseline knowledge for tree breeding. Currently the species is divided into four subspecies: globulus, bicostata, pseudoglobulus and maidenii. Random Amplified Polymorphic DNA (RAPD) markers were used to analyse variation in 173 representatives of 37 natural populations of E. globulus: 31 localities of ssp. globulus (148 individuals), two localities each of ssp. bicostata (nine individuals), ssp. maidenii (ten individuals) and ssp. pseudoglobulus (six individuals). Ten 10-mer primers amplified a total of 162 scorable bands, of which 149 (91.9 per cent) were polymorphic. AMOVA analysis of a Euclidean distance matrix based on presence/absence of polymorphic bands found most variation within localities, but significant differences between localities and regions. Principal components analysis (PCA) identified a major latitudinal dine in RAPD phenotype that differentiated southern Tasmanian localities from other ssp. globulus localities on mainland Australia. Many localities previously identified as intermediate between subspecies globulus and other subspecies in morphology were not intermediate in RAPD phenotype. In some cases regions which showed marked differentiation between localities in capsule and juvenile leaf morphology showed little RAPD differentiation between localities. RAPDs also provided new insights into the affinities of outlying localities.Although RAPD technology has not yet been applied to many forest tree species, patterns of variation were similar to those found in other outcrossing species studied using both RAPDs and other molecular markers.

Progress in Myrtaceae genetics and genomics: Eucalyptus as the pivotal genus

“…In addition to the use of markers for fundamental population genetics studies in Eucalyptus (see Section "Molecular population genetics"), DNA genotyping data have been valuable to assist in the design of seed collections (Nesbitt et al 1995), improve the structure of breeding populations and seed orchards (Marcucci-Poltri et al 2003;Zelener et al 2005), and assess the levels of genetic diversity in national breeding programs. For example, microsatellite markers were used to compare the Australian National E. globulus Breeding Program (n0140) to that observed in native trees (n0340).…”

Population genetic analysis and phylogeny reconstruction in Eucalyptus (Myrtaceae) using high-throughput, genome-wide genotyping

“…Although attempts have been made to develop high-throughput marker systems, it has been difficult to generate large numbers of polymorphic markers that can be applied efficiently to large numbers of samples using techniques such as RFLP (e.g., Byrne et al 1998;Butcher et al 2002), RAPD (Nesbitt et al 1995) and even microsatellites (Steane et al 2001;Brondani et al 1998Brondani et al , 2006. AFLP markers can be scaled up to produce a high-throughput system (Myburg et al 2001), but even with these relatively abundant markers, developing large numbers of reliable, high-quality polymorphic markers is laborious and expensive due to the requirement for gel or capillary electrophoresis.…”

Microsatellite and morphological analysis ofEucalyptus globuluspopulations

“…Within the two large circles are small intergrade populations. put forward (see Kirkpatrick 1975;Jordan et al 1993;Nesbitt et al 1995), but these are inconclusive as they are based on morphological traits (which may be influenced by selection) or have limited sample size.…”