Great Plains sunflower variety trials

<b>Abstract:</b> This dataset contains aggregated data from sunflower (<i>Helianthus annuus</i>) variety trials conducted across multiple locations in the Great Plains, with a primary focus on North Dakota and South Dakota. Spanning from 1978 to 2012, the collection provides standardized performance data for commercial hybrids, covering both oilseed and confection market types under irrigated and dryland conditions.The dataset includes the final quality-controlled compilation (<code>commercial_sunflower_trials.csv</code>) as well as the original raw Excel files and the R scripts used for data standardization.<b>Key variables measured include:</b><b>Agronomic Performance:</b> Yield (lb/acre), oil content (%), test weight (lb/bushel), and seed weight.<b>Phenology:</b> Days to flowering (50%), physiological maturity, and harvest moisture.<b>Morphology:</b> Plant height and head diameter.<b>Management:</b> Planting and harvest dates, irrigation status, and geographic coordinates (latitude/longitude) for trial locations.This resource is designed to support research into historical crop performance, genotype-by-environment interactions, and long-term breeding trends in sunflower production.<br><b>*Review the README.md for detailed information about this resource.</b>