Given the growing interest in multipurpose hemp crop, eight monoecious cultivars were compared in a two-year trial for quantitative and qualitative yield in a Mediterranean environment characterized by a temperate and humid climate with hot summers. All hemp cultivars were evaluated for yield potential of (i) seed plus stem at seed maturity, and (ii) essential oil yield from inflorescences harvested at full flowering. The second goal was set to test the ability of cultivars to supply new seeds after the removal of inflorescence at full flowering. Among the cultivars, Fedora obtained the best results for seed (0.79 and 0.52 t ha⁻¹) and vegetable oil yield (0.17 and 0.09 t ha⁻¹) normally and with inflorescence removed plants, respectively. Futura, conversely, showed the best results for inflorescence (3.0 t ha⁻¹), essential oil (9 L ha⁻¹), and stem yield at seed maturity (8.34 t ha⁻¹), as means across the two years. The cultivars studied generally reached the grain-filling stage during a period that was drier and warmer than the average of the same multi-year period, and this negatively affected seed quality. The oil fatty acid composition was mainly composed of polyunsaturated fatty acids (75% on average) and not affected by the cultivar. In conclusion, although the hemp grower should always clearly know the main production objective of the crop, the monoecious cultivars available today allow a multipurpose use of hemp crop, improving the sustainability of the cultivation activity.

The seed yield in hemp (Cannabis sativa L.) is strongly influenced, besides by genotype, by environment and the genotype x environment interaction, so establishing the fitness and stability of hemp cultivars in multiple environments is necessary. The purpose of this study was to investigate the performance and degree of stability and variance of seed yield, the main related traits, and the correlation among the traits in five hemp monoecious cultivars cultivated in six different environments. The environments resulted from the combination of four locations, two years, and two delayed sowings in a Mediterranean area of north-eastern Italy, and the stability index of the weighted average of absolute scores (WAAS) was used in order to identify the most productive and stable genotypes on the basis of their deviation from the average performance across environments. In this studied area, early varieties, such as Fedora and Felina, proved to be the best performing and stable for seed yield and both increased their yield in correspondence to delayed sowing times, opening up the possibility of cultivating hemp as a second crop. Among the climate parameters, high temperatures during the early grain filling period led to a progressive decrease in seed yield. For a dual-purpose crop, a good compromise could be a late monoecious cultivar (like Futura, in the present experiment), which, if sown early, could certainly provide notable biomass production and acceptable seed yield.