Switchgrass sward establishment selection is across multiple environments and fertilization levels

Background: Strong selection can occur during switchgrass sward establishment.  Differences in establishment selection due to environment or management could provide information on genotype‐by‐environment variation and could influence strategies for breeding perennial grasses.
Methods: Leaf samples were collected before sward establishment and from 3‐year‐old swards for two breeding groups (lowland and hybrid) at three locations. Within two locations, samples were collected from paired fertilized (110 kg ha-1 N) and unfertilized plots. Allele frequencies from pooled DNA samples were studied through multivariate analysis of variance, genomewide trait predictions (heading date and winter survivorship), and genomically estimated breeding values (GEBVs) for individual sward survival within an independent data set.
Results: This study found only minor variations in selection due to location or management. Predicted heading dates of the hybrid population had significant changes due to fertili..., This dataset includes breeding populations of switchgrass half-sib families derived from the Liberty cultivar which were planted at three locations (Arlington, WI, Prairie du Sac, WI, and Hancock, WI).  Collectively, these will be referred to as the hybrid breeding population.  These families were collected from two generations of genomic selection, which will be referred to as G1 and G2.  A small number of diverse families from the gulf ecotype were also sampled with fewer replicates and will be referred to as the gulf breeding population. 
The Arlington half-sib families are from swards within a previously published study evaluating the impact of plant spacing and will be referred to as SPACE (https://doi.org/10.1002/glr2.12007). The Prairie du Sac and Hancock families are from a separate study evaluating the impact of nitrogen fertilization and marginal land sites, referred to as SLOW (Casler, in progress). The SPACE study was planted with 19 hybrid half-sib families from G1 and G2 ...,