Forecasting the genetic and economic impacts of genomic selection in perennial ryegrass

Abstract

Simulation offers a way to explore questions about implementation, value and impacts of various breeding methodologies for pasture species in New Zealand (NZ).  We present genetic modelling and farm system-based economic simulations demonstrating the potential of genomic selection (GS) and high-throughput phenotyping (HTP) to improve breeding outcomes in perennial ryegrass, and assess the potential value for farmers.  Predicted genetic gain (∆G) from half-sibling family selection without GS ranged up to 4.9% per cycle, depending on selection pressure. Including GS for within-family selection, ∆G ranged up to 7.6% per cycle. Across 12 scenarios tested for a single cycle, increasing ∆G per cycle doubled cost-efficiency per unit gain, even though cost per cycle increased.  Simulation of 10 cycles of selection within a population with and without GS showed higher levels of ∆G were maintained over multiple cycles for GS.  Farm system-based economic analysis, focused on agronomic traits, indicated full commercialisation of GS and HTP technology harnessing increased ∆G in 2026 creates new value rising by 2040 to a range of $74M - $221M per annum for NZ red meat farmers, and $399M to $1,260M per annum for dairy farmers in NZ and Australia.  This study indicated incorporating GS in pasture plant breeding can increase the rate and cost-efficiency of genetic improvement, with pasture performance and sector economic benefits realised through the value chain.