Microsatellite allele length variations in inter-specific hybrids of Eucalyptus

Abstract

-The genus Eucalyptus encompasses several species of industrial importance. Many of these species have been subjected to genetic characterization using different kinds of DNA markers. More than 1000 microsatellites have been identifi ed from the genome of eucalypts and they are highly amenable for cross species transferability. During cross amplifi cation of microsatellites, homoplasy is reported in many species in which although the allele size might be the same, the sequences are not. Thus, it is essential to ascertain the DNA sequence homology with source and target microsatellite repeats. Accordingly, fifty five alleles from six microsatellite loci (ECc1, ECc2, Eg61, Embra100, Embra1468 and Embra2002) were amplifi ed in two inter-specifi c hybrid populations (Eucalyptus tereticornis × E. grandis and E. tereticornis × E. camaldulensis) and sequenced. The results showed that all the microsatellite loci were amplifying the target repeat types except for the loci Eg61 and Embra2002. The locus Eg61 has target repeat of (CAA)(GAT) but the sampled alleles had either (CAA)(GAT) or (GAT) alone. Similarly, the Embra2002 locus was targeting interrupting repeats of (CCA)..(CCA), but the sequenced alleles had repeats of (CCA) with or without interruption. Nevertheless, the allele size estimated in electrophoresis for hybrids was in conformity with that of the parent alleles. This study suggests the need for validation of the repeat characteristics of microsatellites by sequencing of the alleles particularly in cross species amplifi cation.

Biomass productivity and wood chemical composition at different pruning ages of interspecific hybrid Jatrophas

“…Interspecific hybridization is an approach to broaden the genetic base of plants. Other research has shown that interspecific hybridization increased biomass yields in several fast-growing species, including willow (Gramlich et al, 2018), poplar (Barghini et al, 2015), eucalyptus (Sumathi and Ramasamy, 2017) and leucaena (Brewbaker, 2013). Jatropha has low genetic diversity (Laosatit et al, 2014), making it less likely to produce enough trait variability to select new superior genotypes.…”

Biomass yield stability of interspecific Jatropha hybrids through multiple harvest rotations with varying harvest ages

“…Interspecific hybridization is one method for developing plant genotypes; recently, it has been applied to enhance biomass yields in several short-rotation woody crops, such as willow (Gramlich et al, 2018), poplar (Barghini et al, 2015), eucalyptus (Sumathi and Ramasamy, 2017) and Leucaena (Brewbaker, 2013). Jatropha has a low genetic diversity (Laosatit et al, 2014), making it less likely to provide enough phenotypic variability to select new elite genotypes.…”