The medicinal use of cannabinoids renewed the interest in industrial hemp (Cannabis sativa L.). The aim of this study was to evaluate the impact of growth stage and biomass fractions of seven industrial hemp genotypes. The study focused on biomass yield, content of cannabidiolic acid/cannabidiol (CBDA/CBD), cannabigerolic acid/cannabigerol (CBGA/CBG), and tetrahydrocannabinolic acid (THCA). The experiment was conducted in 2017 and 2018. The biomass samples were taken at the vegetative (S1), bud (S2), full-flowering (S3) and seed maturity stage (S4). Plants were fractionated into inflorescence, upper and lower leaves. The average inflorescence dry yield of genotypes Futura75, Fédora17, Félina32 and Ferimon ranged between 257.28 g m−2 to 442.00 g m−2, resulting in a maximum yield of CBDA at S4, with 4568.26 mg m−2, 6011.20 mg m−2, 4975.60 mg m−2 and 1929.60 mg m−2, respectively. CBGA was exclusively found in genotype Santhica27, with a maximum CBGA yield of 5721.77 mg m−2 in inflorescence at growth stage S4 and a dry weight yield of 408.99 g m−2. Although these industrial hemp genotypes are mainly cultivated for fibre and seed production, however, cannabinoids offer an additional value. For an optimized harvest result, yield of extractable material and overall yield of cannabinoids must be considered.

Fusarium head blight (FHB) is a devastating disease of wheat. Worldwide, Fusarium graminearum is the most dominant FHB-causing species. Its most common toxin, deoxynivalenol (DON), impairs food and feed safety and has an enormous economic impact. Agronomic factors such as crop rotation, soil management and host genotype strongly influence the occurrence of F. graminearum. Infected plant debris from previous crops, on which perithecia and ascospores develop, represent the main source for FHB, and hence, improved cropping systems aim to reduce this inoculum to decrease the infection risk. The best measure to evaluate the disease pressure is spore traps that detect deposited airborne ascospores. Commercial spore traps are expensive and require power sources, thus, they are not suitable for investigations in field experiments with different treatments. In consequence, we developed spore traps containing a Petri dish with Fusarium-selective agar, protected by aluminum dishes and attached on a wooden board. We compared the data of our low-cost trap with those of a commercial high-throughput jet sampler and obtained equivalent results. In field experiments to compare cropping systems, we observed a high correlation between the DON content in wheat grains and the number of colonies from deposited spores. Our spore trap proved to be a highly valuable tool to not only study FHB epidemiology but also to identify innovative cropping systems with a lower risk for FHB and DON contamination.

The aim of this study was to adapt the CROPGRO model to simulate growth and development processes of Amaranthus spp. under central European conditions. In 2017 and 2018, two field experiments with two amaranth cultivars (grain type, A. hypochondriacus L. Neuer Typ [NT]; fodder type, A. caudatus L. K63 [K63]) were conducted in southern Germany. Based on experimental and literature data, parameter coefficients that drive physiological processes at species, cultivar, and ecotype levels were calibrated to predict the time series experimental observations of various growth and development traits. Statistical evaluation of the model adaptation was performed using root mean square error (RMSE, in variable units, 0 equals perfect fit) and the Willmott agreement index (d-Stat., range from 0 to 1, 1 equals perfect fit). For NT and K63, respectively, the model adaptation led to accurate predictions of canopy height (RMSE, 0.07 and 0.24 m; d-Stat.,0.98 and 0.92), panicle weight (RMSE, 2,034 and 1,153 kg ha -1 ; d-Stat., 0.92 and 0.94), panicle harvest index (RMSE, 0.05 and 0.06; d-Stat., 0.99 and 0.96), leaf N concentration (RMSE, 0.38 and 0.40%; 0.94 and 0.92) and aboveground biomass (RMSE, 2,948 and 2,572 kg ha -1 ; d-Stat., 0.88 and 0.91). In summary, the CROPGRO model was successfully adapted for Amaranthus spp. The adapted model can be further improved as it is made available for evaluation in different locations and environments including limited soil N supply.