Genetic and environmental variation in alfalfa forage yield from variety testing experiments conducted in North America between 1986 to 1999

<p>The yield dataset contains forage yield data from over 700 alfalfa variety tests conducted by researchers in the US and Canada from 1986 through 1999. Some trials also measured forage quality and stand; these data are also available in PURR. The data were aggregated from the Alfalfa Variety Performance Database originally compiled in 2000 by Daniel W. Wiersma and Wayne G. Hartman (doi: <a href="https://doi.org/10.4231/PHKH-4334" target="_blank">10.4231/PHKH-4334)</a>. The database was used to analyze long-term trends in genetic improvement of alfalfa yield and agronomic performance across a broad range of environments.</p>

<p>The yield file contains cultivar-specific yield data for each harvest within a year. It is organized by Trial, and includes trial-specific spatial (state, latitude, longitude, elevation), and temporal (year of trial, harvest number, harvest date, planting date) details. Finally, when available soil type and statistics are also provided. A companion dataset in PURR contains the characteristics of these alfalfa varieties (doi: <a href="https://doi.org/10.4231/FMY9-6966" target="_blank">10.4231/FMY9-6966)</a>. </p>