Comparing agronomic performance of industrial hemp varieties for suitable production in the United States

Abstract

Industrial hemp (Cannabis sativa L.) is an ancient crop used throughout history for fiber, oilseed, and therapeutic compounds. Hemp varieties were cultivated across diverse environments in the United States, but knowledge of those agronomic practices along with genetic resources was lost during a period in which cultivation of cannabis was prohibited. Therefore, regional performance evaluations of hemp varieties for crop performance coupled with scientific communication of outcomes to the public are crucial for hemp's development as an agricultural commodity. Objectives for this research were to evaluate relative yields of industrial hemp varieties grown across the United States and link their suitability for commercial production across locations. A national collaboration established variety trials containing seven industrial hemp varieties planted across 14 locations (36°–48° N latitude and 72°–110° W longitude) over a 3-year period. Crop dry straw yield and seed yield increased from the averages of 1600 and 700 kg ha⁻¹ in Year 1 to 2400 and 1150 kg ha⁻¹ in Year 2, and 3050 and 815 kg ha⁻¹ in Year 3, respectively. The varieties Anka and X-59 performed best in Vermont and Virginia, where seed yields consistently exceeded 1100 kg ha⁻¹; however, no single variety performed above average across all sites. Overall, this assessment identified two industrial hemp varieties suitable for commercial production in specific sites and highlighted the importance for hemp breeders to investigate variety × location × year interactions when developing improved varieties to best capture site-specific productivity.