Five monoecious (Uso-31, Carmaleonte, Codimono, Futura 75, and Felina 32) and six dioecious (Bernabeo, Carmagnola, CS, Fibranova, Fibrante, and Eletta Campana) European industrial hemp genotypes were cultivated in an open field for two consecutive years. The main characteristics of the cultivated plant material—including chemotypes, flower type, and flowering time—are reported in Table 1.
| Table 1. Agronomic trial data from the years 2019–2020. Height is expressed in cm, the diameter at the collar in mm, the density as number of plants/m2, and the dried inflorescences yield as g/m2.
|
| Genotype
|
Chemotype
|
Flower type
|
Flowering time
|
Sowing date
|
Harvest date
|
Height
|
Collar diameter
|
Plant density
|
Dried inflorescences yield
|
| 2019
|
2020
|
2019
|
2020
|
2019
|
2020
|
2019
|
2020
|
2019
|
2020
|
2019
|
2020
|
| Carmaleonte
|
III
|
Monoecious
|
Medium
|
19 April
|
23 April
|
16 September
|
16 September
|
177 ± 42.5
|
223.6 ± 35.7
|
7.9 ± 2.8
|
13.8 ± 3.3
|
62 ± 24
|
2.2 ± 1.1
|
460
|
20
|
| Codimono
|
III
|
Monoecious
|
Medium
|
19 April
|
23 April
|
25 September
|
16 September
|
183 ± 39.9
|
255.2 ± 32.8
|
6.6 ± 2.2
|
13.0 ± 3.6
|
77 ± 27.2
|
5.7 ± 0.7
|
440
|
51
|
| Futura 75
|
III
|
Monoecious
|
Medium
|
19 April
|
23 April
|
18 September
|
16 September
|
77.3 ± 17.6
|
238.6 ± 58.2
|
255.6 ± 4.9
|
13.1 ± 4.4
|
8.6 ± 0.3
|
7.4 ± 1.3
|
71
|
67
|
| Felina 32
|
III
|
Monoecious
|
Medium
|
4 June
|
23 April
|
20 September
|
16 September
|
151 ± 33
|
222.3 ± 43.3
|
5.9 ± 1.9
|
13.3 ± 4.5
|
61.3 ± 23.8
|
4.2 ± 1.5
|
160
|
40
|
| Uso-31
|
V
|
Monoecious
|
Early
|
4 June
|
23 April
|
20 September
|
31 August
|
108 ± 31
|
184.4 ± 26.0
|
5.2 ± 1.9
|
11.6 ± 2.3
|
60.6 ± 11.3
|
3.2 ± 0.3
|
200
|
29
|
| Bernabeo
|
IV
|
Dioecious
|
Late
|
19 April
|
23 April
|
28 September
|
8 October
|
211.6 ± 50.1
|
277.3 ± 38.9
|
8.6 ± 2.8
|
19.5 ± 6.7
|
64.3 ± 15.3
|
4.3 ± 3.2
|
430
|
39
|
| Carmagnola
|
III
|
Dioecious
|
Late
|
19 April
|
23 April
|
9 October
|
8 October
|
228.3 ± 44.8
|
272.4 ± 34.5
|
8.2 ± 2.5
|
19.2 ± 5.1
|
61 ± 1
|
2.7 ± 2.0
|
410
|
24
|
| Fibranova
|
III
|
Dioecious
|
Late
|
19 April
|
23 April
|
30 September
|
8 October
|
273.7 ± 45.6
|
314.5 ± 34.8
|
9.4 ± 2.8
|
17.1 ± 5.0
|
78.3 ± 14.4
|
6.3 ± 3.2
|
440
|
57
|
| Fibrante
|
III
|
Dioecious
|
Late
|
19 April
|
23 April
|
11 October
|
8 October
|
269.1 ± 47.6
|
202.8 ± 5.2
|
10.1 ± 2.7
|
15.0 ± 1.3
|
85.3 ± 11
|
0.7 ± 0.4
|
420
|
6
|
| Eletta Campana
|
III
|
Dioecious
|
Late
|
19 April
|
23 April
|
16 October
|
8 October
|
260.3 ± 44.3
|
304.5 ± 40.4
|
9.1 ± 2.6
|
17.5 ± 3.6
|
94.7 ± 29.1
|
5.7 ± 2.1
|
420
|
51
|
| CS
|
III
|
Dioecious
|
Late
|
19 April
|
23 April
|
1 October
|
8 October
|
246 ± 51.8
|
333.7 ± 37.5
|
9.2 ± 3
|
18.1 ± 3.8
|
60.3 ± 22.3
|
6.3 ± 1.7
|
440
|
57
|
|
Sowing was performed on April 19, 2019 and April 23, 2020, with a 25 cm distance between rows on randomized blocks with three repetitions, and a plot size of 20 m2.
The harvest date differed according to the flower behavior and flowering time of each genotype. Generally, monoecious and early-flowering strains were harvested earlier than dioecious and late-flowering genotypes in both years (Table 1).
The comparison between plant heights showed differences between the two years, with higher plants obtained in 2020. The same trend was observed when comparing plant collar diameters. Plant density, defined as number of plants/m2, and dried inflorescences yield, measured as g/m2, were significantly lower in 2020, while dried inflorescences yield calculated for single plant was by far higher in 2020 than in 2019. These differences in plant growth in the two years of cultivation could be due to the lack of rainfall in the pre- and post-emergence period of 2020, compared to that of 2019, which could have caused a reduced germination rate and, therefore, a lower plant density. Conversely, 2019 was very rainy in May and June, favoring seed germination and following plant density. This rainfall trend was inverted in June; indeed, the rainy period (July and August) in 2020 could have allowed for a biomass production greater than that observed in 2019, as is clearly shown in Table 1. Finally, September 2019 was rainier than 2020, and this could have influenced the EOs’ yield.
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