Can topping and harvest time affect performance and potentiality of monoecious and dioecious hemp (Cannabis sativa L.) varieties?

Hemp potential as a multiuse crop is one of the main features that has fuelled the recent come back of interest over the cultivation of hemp. In fact, the high diversity of the obtainable final products characterizes hemp as an ecologically friendly multi-purpose crop, exploitable in a large number of agro-industrial sectors, ranging from textiles, modern bio-composites, to functional foods, cosmetics and pharmaceutical purposes (Crini et al., 2020). Hempseed oil is considered an excellent functional food thanks to high levels of polyunsaturated fatty acids (80%), with an optimal omega-6 to omega-3 ratio (Callaway, 2004). Besides, the recovery of non-psychoactive cannabinoids - cannabidiol (CBD) and cannabidiolic acid (CBDA) - from industrial hemp by-products (stems, leaves and threshing residues) can be feasible with economic potential, further qualifying this plant as a multipurpose crop. Despite significant progress made by the international research community on chemical and nutraceutical characterization of hemp products, the agronomic management practices involved in growing hemp for seeds remains insufficiently investigated. So, the aim of the present work was to assess the effect of topping and harvest time on seed yield and CBD content and composition of threshing residues of Futura 75 and Carmagnola hemp cultivars, cultivated in Northern Tuscany (Italy).