Genomic breeding for accelerated improvement of growth, wood properties and plant defence in Eucalyptus grandis

Abstract

A significant benefit of genomic selection (GS) in forest trees is to reduce breeding cycle times and increase gains per unit time. Flowering time (seed-to-seed) of many forest tree species is a crucial factor contributing to the length of breeding cycles. In this study, we investigated the benefits of combining GS with transgenic Flowering locus T (FT)-scion for early floral induction (GS-FT) transgrafting approach in the precocious Eucalyptus grandis and non-precocious E. dunnii, two economically important plantation species. We simulated traditional breeding (TB), GS and GS-FT in the species and compared their transitional cost ratio and their benefit-cost ratio in terms of genetic gain. Implementation of GS and GS-FT compared to TB strategy was 10 to 13.8 fold more expensive for both species. Whereas the transition from GS to GS-FT strategy in both species is 1.2 fold more expensive. This resulted in a punitive benefit-cost ratio implementing GS and GS-FT strategies compared to the TB strategies. The implementation of the GS-FT, compared to the GS strategy, had a profitable benefit-cost ratio. With the adoption of the GS-FT strategy, which effectively removes flowering time as a barrier, similar breeding cycle times are achieved in both species, but E. dunnii benefits more due to the significant reduction in breeding cycle time. Our simulation provides a first indication of the potential benefits of implementing FT floral induction in conjunction with GS breeding strategies in plantation forest species.

Description

Thesis (PhD (Genetics))--University of Pretoria, 2022.

Keywords

Genomic selection, Single-step genomic BLUP, Breeding cycle, Genetic gain, Accelerated breeding, UCTD

Sustainable Development Goals

Citation

Mphahlele MM, Isik F, Hodge GR and Myburg AA (2021) Genomic breeding for diameter growth and tolerance to Leptocybe Gall Wasp and Botryosphaeria/Teratosphaeria Fungal Disease Complex in Eucalyptus grandis. Frontier in Plant Science. 12:638969. doi: 10.3389/fpls.2021.638969