Comparison of Eucalyptus grandis Provenances and Seed Orchards in a Frost Frequent Environment

Abstract

SYNOPSISAn international provenance trial of Eucalyptus grandis was established in southern Florida in 1980 and measured for growth and frost-tolerance through 8,8 years. The trial compared 20 Australian provenances 1) among themselves and 2) with seed orchard stock from Florida and South Africa. Florida orchard seedlots grew better than nearly all other material, including a South African clonal seed orchard bulklot. Provenance variability was significant for growth, survival. and frost-tolerance. with some provenances notably more frost-tolerant than provenances previously introduced into the Florida breeding population. Only the Herberton provenance was comparable to advanced-generation Florida seedlots in all critical traits. Importation of some provenances from the northern part of the species range may be warranted to broaden the genetic base of E. grandis in Florida. Further comparisons in a supplemental study and a Florida genetic base population also noted variation between relatively close provenances and provenances by site interaction for growth characteristics. Provenances superior as early as age one year in the field were usually best at 8,8 years, but the tallest seedlings in the nursery did not maintain superiority in the field. Soil types influenced growth significantly, and provenance x soil type interactions were common. Single-tree plots evaluated provenances much more efficiently than block plots.

Genome scans for divergent selection in natural populations of the widespread hardwood species Eucalyptus grandis (Myrtaceae) using microsatellites

“…Of note, E. grandis displays significant variation in adaptive phenotypic traits, such as growth and frost tolerance (e.g. Rockwood & Meskimen 22 ). A relatively low level of population differentiation has been revealed in E. grandis by isozyme markers ( G ST = 0.12) 23 , suggesting a weak population structure.…”

Genomic consequences of artificial selection during early domestication of a wood fibre crop

“…Cultivation of E. grandis as a timber and wood fibre crop has been ongoing for over 100 yr in various exotic environments around the world (Bennett, 2011). From its origins in Australia, the species has been transplanted to every continent except Antarctica (Marco, 1991; Rockwood & Meskimen, 1991; Huoran et al ., 1992; Chaix et al ., 2003; Hunde et al ., 2003; Dos Santos et al ., 2004; Verryn et al ., 2009; Luo et al ., 2010; Boulay et al ., 2012; Santos et al ., 2017). Its fast growth has been further improved in exotic breeding programmes where artificial selection resulted in trees reaching harvestable age 10–15% earlier (Verryn, 2002), and produced increases of 16% in stem volume per generation of breeding (Meskimen, 1983).…”

“…Its fast growth has been further improved in exotic breeding programmes where artificial selection resulted in trees reaching harvestable age 10–15% earlier (Verryn, 2002), and produced increases of 16% in stem volume per generation of breeding (Meskimen, 1983). These improvements in growth resulted, in part, from the selection of genotypes better adapted to the exotic environment (Rockwood & Meskimen, 1991) and an expanded range of genotypes produced by intraspecific hybridization resulting from crosses between individuals from different provenances. Other economically important traits such as stem form and wood properties were also improved by artificial selection (Verryn et al ., 2009).…”

History and Status ofEucalyptusImprovement in Florida

“…Including the genetic base populations that served as large open-pollinated progeny tests, some 25 smaller progeny tests of E. grandis in GO73 and GO77 were planted in southern Florida since the 1970s [7,12,16,17,[20][21][22][23][24][25]. GP77 and eight of these smaller tests with appropriate tree size and freeze responses, in combination with the multigeneration pedigrees that have been maintained, have recently contributed to the calculation of breeding values for 2,174 trees for stand basal area and/or freeze resilience (the ability to reestablish vigorous vertical growth after freeze damage).…”

“…In the early 1970s, a eucalyptus research cooperative was formed by seven companies to provide financial and research support to the Forest Service. This effort led to the selection of E. grandis, E. robusta, E. camaldulensis, and E. tereticornis from 67 species tested and to the development of cultural practices for raising seedlings and establishing commercial plantations in southern Florida [1][2][3][4][5][6][7][8][9][10][11][12][13].…”