Looking at the past to prepare ahead: Adapting Red Clover for future New Zealand climates

Abstract

Developing adaptive, resilient pastural cultivars is crucial for maintaining New Zealand’s (NZ) highly productive farming sector. With growing challenges from climate change, including heat and extreme rainfall, identifying genetic material that provides resilience is vital. Wild populations, shaped by their local environmental pressures and isolation, hold unique gene makeups that can help develop climate-adaptive cultivars. In this study, we examined the genetic response of 92 internationally geographically diverse red clover populations to their source bioclimatic environments using partial redundancy analysis. The aim was to identify bioclimatic variables driving environmental adaptation and the resulting DNA variants (outlier single nucleotide polymorphisms (SNPs)) associated with adaptation. Calculation of adaptive indices and genomic offset values enabled us to predict the suitability of these populations to future NZ environments. We found that Annual mean diurnal range, Isothermality (variance in daily temperature relative to annual variation), Mean temperature of the wettest quarter, and Precipitation seasonality underpinned adaptive genetic variation. Forty-two outlier SNPs strongly associated with key bioclimatic variables show potential as markers for climate-resilient breeding. Mapping adaptive indices and genomic offset values to NZ’s current and predicted future climates showed the genetic diversity captured in these germplasm populations could help develop future-proofed adaptive cultivars.