Selection strategy for a seedling seed orchard design based on trait selection index and genomic analysis by molecular markers: a case study for Eucalyptus dunnii

Abstract

Molecular genetic analysis was applied to 162 individuals of 37 half-sib selected families belonging to six provenances of Eucalyptus dunnii Maiden in a provenance/family trial. The individuals were selected by a trait selection index and genetic diversity criteria were later applied for designing seedling seed orchards. Genetic diversity and its distribution, as well as relationships among individuals, were assessed on the basis of nine microsatellite loci and 243 amplified fragment length polymorphism markers. High diversity was found with both kinds of markers. Clear-cut genomic patterns of identification (fingerprinting) were obtained for each individual. Genetic differentiation estimates consistently showed low differentiation among provenances (R(ST1) = 0.069, theta(P) = 0.026 and F(CT) = 0.035) and great differentiation among families (R(ST2) = 0.223, theta(S) = 0.174 and F(SC) = 0.164). A high proportion of the total variation was observed within families (around 80% by both marker analyses), suggesting that orchard design should be based on individual or family selection rather than on provenance selection, and that individual ranking by both trait selection index and molecular genetic diversity criteria should be considered. A selection procedure for a seedling seed orchard design is proposed.

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).…”

Microsatellite resources of Eucalyptus: current status and future perspectives

“…Parentage assignments based on microsatellite allele information could lead to the identification of appropriate parents contributing for potential progeny (Grattapaglia et al [2004]a). Microsatellite diversity was considered for the designing of seed orchard in E. dunnii (Zelener et al [2005]) and E. globulus (Dini et al [2011]) thus reducing the risks of inbreeding. Eucalyptus has predominantly outcrossing breeding system, nevertheless the rate of outcrossing varies among the species and populations.…”

Use of SSR-Tools for clone certification in Uruguayan Eucalyptus grandis and Eucalyptus dunniibreeding programs

“…This could generate a labeling system to follow the material traceability in companies with large-scale production of clonal nurseries. Proper identification makes new clones releasing easier and improves the management of seed orchards and controlled pollination breeding programs [4-6]. The aim of this study was to characterise 24 elite clones of several breeding programs in Uruguay, by the use of microsatellites.…”