Crambe abyssinica a non-food crop with potential for theMediterranean climate: Insights on productive performances and root growth

tWithin a framework of renewed interest in crambe (Crambe abyssinica Hochst ex R.E. Fries) sourcing rawmaterials for the bio-based industry, the adaptability and productive performances of this oil crop havebeen evaluated under contrasting Mediterranean environments (i.e., a fertile site in the northern part ofPo valley vs. a semi-arid site of southern Sicily) during two consecutive growing seasons, aiming at its pos-sible stable introduction in this area. The trial set in northern Italy compared three commercial varietiesof crambe (Galactica, Nebula and Mario) in spring sowing, while in southern Italy only the var. Mario wastested with autumn sowing. Regardless of location and variety, thermal time for maturity was quite stable(1200–1400◦C), and the crop provided satisfactory seed yields (grand mean 2.29 Mg hulled seeds ha−1),with average oil content of ∼400 g kg−1(on dehulled seeds) and ∼52% of erucic acid. Significantly higherseed and oil yields were reached in northern than in southern Italy. Furthermore, crambe thermal useefficiency (THUE) was also higher in the north than in the south, possibly due to better environmentaladaptability of the crop. The limited intraspecific variability within crambe was confirmed, with betterproductive performances showed by the domestic selection Mario. Promising traits were revealed inNebula, showing greater seed weight, root length density and area, and thinner roots, although the rootgrowth of crambe was generally modest compared with modern high erucic acid rapeseed hybrids. Avail-able crambe varieties could be efficiently included in crop rotations across a wide range of environmentswithin the Mediterranean basin. The short growth cycle represents an outstanding added value for thisspecies, allowing the avoidance of prolonged drought and heat stress typical of late spring/early summermonths under the Mediterranean climate. However, increased yields are needed to meet the marketrequests; nonetheless, the little genetic variability suggests that there is large scope for future breedingimprovements, maybe exploiting advanced techniques to improve the existing genetic resources.