16S rRNA V4 metabarcoding of root-associated microbiomes of European Zea mays L. landraces and modern varieties grown in the field under ambient and 60% reduced precipitation

Maize varieties representing two distinct breeding eras (six landraces released pre-1945 and six modern varieties released post-2010) were grown in a field with silt loam/Luvisol near Pocking, Germany, in two growing seasons (2021 and 2022). Plants were subjected to two precipitation treatments: natural rainfall and a 60% reduction in precipitation induced by rain-out shelters. Composite samples encompassing the rhizoplane and root endosphere were collected at the grain-filling stage. The V4 region of the 16S rRNA gene was sequenced to assess the composition of the prokaryotic microbiome.