Genotype × environment interaction analysis of North American shrub willow yield trials confirms superior performance of triploid hybrids

Abstract

Development of dedicated bioenergy crop production systems will require accurate yield estimates, which will be important for determining many of the associated environmental and economic impacts of their production. Shrub willow (Salix spp) is being promoted in areas of the USA and Canada due to its adaption to cool climates and wide genetic diversity available for breeding improvement. Willow breeding in North America is in an early stage, and selection of elite genotypes for commercialization will require testing across broad geographic regions to gain an understanding of how shrub willow interacts with the environment. We analyzed a dataset of first-rotation shrub willow yields of 16 genotypes across 10 trial environments in the USA and Canada for genotype-byenvironment interactions using the additive main effects and multiplicative interactions (AMMI) model. Mean genotype yields ranged from 5.22 to 8.58 oven-dry Mg ha À1 yr À1. Analysis of the main effect of genotype showed that one round of breeding improved yields by as much as 20% over check cultivars and that triploid hybrids, most notably Salix viminalis 9 S. miyabeana, exhibited superior yields. We also found important variability in genotypic response to environments, which suggests specific adaptability could be exploited among 16 genotypes for yield gains. Strong positive correlations were found between environment main effects and AMMI parameters and growing environment temperatures. These findings demonstrate yield improvements are possible in one generation and will be important for developing cultivar recommendations and for future breeding efforts.

Electrical capacitance as a predictor of root dry weight in shrub willow (Salix; Salicaceae) parents and progeny

“…Increased vigor can be observed in intraspecific crosses of shrub willow, but the effect is generally more dramatic in the progeny of interspecific crosses (Serapiglia et al, 2014), especially in triploid progeny derived from the hybridization of tetraploid and diploid parents (Serapiglia et al, 2015; Fabio et al, 2016). Likewise, we show that the interspecific families 421, 423, and 430 had significantly higher means for REC compared to their respective midparent values (Fig.…”

Poplar and shrub willow energy crops in the United States: field trial results from the multiyear regional feedstock partnership and yield potential maps based on the PRISM‐ELM model

“…The large amount of unexplained variation is undoubtedly due to the vagaries of G × E interactions, pest damage, disease pressure, crop management, soil conditions, and weather. While there was some consistency in the top three cultivars in both the poplar and willow trials, it was not absolute, indicating the existence of G × E interactions, as has been previously reported (e.g., Fabio et al ., ,b). The decision to use the top three cultivars at each specific site was intended to capture the best yield potential at each site.…”

Breeding progress and preparedness for mass‐scale deployment of perennial lignocellulosic biomass crops switchgrass, miscanthus, willow and poplar

“…Based on collections from thousands of wild prairie remnants, the genetic resources are roughly divided into lowland and upland ecotypes and there are distinct clades within each ecotype which occur along both latitudinal and longitudinal gradients Lu et al, 2013; . Ongoing trials on heavy metal contaminated soils indicate tolerance by exclusion (Krzyżak et al, 2017) Different hybrids are needed for different zones Best hybrids show some G × E (US), and some hybrids low G × E (Fabio et al, 2017)…”