GEM Project-Derived Maize Lines Crossed with Temperate Elite Tester Lines Make for High-Quality, High-Yielding and Stable Silage Hybrids

Maize silage is fundamental for high milk production in dairy farming. The incorporation of new genetic diversity into temperate maize germplasm has the potential to improve adapted cultivars, and it could be especially useful for improving the nutrition of silage varieties. The goal of this study is to assess the potential for lines from the Germplasm Enhancement of Maize (GEM) project to compete with commercial silage hybrids when crossed with elite temperate-adapted testers. We examined 35 GEM-derived hybrids along with five commercial checks in seven environments across three years in trials that were arranged in randomized complete block designs. Hybrids were compared based on their potential for conversion into animal productivity units: milk yield per hectare (Milk ha(-1)) and milk yield per ton of silage (Milk t(-1)). Broad phenotypic variation was observed for both traits, and the broad-sense heritability of Milk ha(-1) and Milk t(-1) were 0.24 and 0.31, respectively. Five out of six hybrids in the top 15%, based on a multi-trait stability index, were GEM-derived hybrids. The large proportions of phenotypic variance attributed to genotype by environment interactions (GEI) for quality traits suggests that local adaptation should be leveraged for silage breeding that make use of GEM-derived materials.