Hemp (Cannabis sativa L. var. sativa) represents the current improvement of modern diets because of its favorable nutritional composition. It contains nutritionally important proteins and oil with a favorable fatty acid composition. The study examined the influence of the variety on the nutritional composition of hemp seeds produced in a field experiment in 2017 in Ljubljana, where nine different varieties were used: Fedora 17, KC Dóra, Santhica 27, Kompolti hybrid TC, Monoica, Futura 75, Helena, Tiborszallasi and USO 31. The results indicated that there are differences between varieties in the yield of crude proteins and fats per unit of production and in the content of fat, while the varieties did not prove to be different in protein content. The crude protein content was between 19.0 % and 22.6 % and the fat content was between 18.2 % and 28.6 %. From the point of view of the nutritional composition and yield of raw proteins/fats (kg/ha), the varieties Futura 75, Tiborszallasi and KC Dóra turned out to be the most interesting varieties in the conditions of the experiment in 2017.
COBISS.SI-ID: 9134713
This study presents the results of fibre procurement from different hemp varieties, targeting the isolation of single fibres rather than fibrous agglomerates. In order to separate fibres from the whole plant, enzymatic retting and mechanical removal were employed. Pectin that connects bast fibres in hemp stalk is necessary to be removed in order to isolate single fibres; pectins are structural polysaccharides contained in the primary cell wall and their decomposition is usually achieved by enzyme action. Analysis of tensile properties and fineness of hemp fibres was conducted according to standardised methods with dynamometer, while morphological examination of hemp fibres was performed with an electron scanning microscope. Morphology of enzymatically-treated fibres showed a wide variety of structural features within one single variety, let alone when different varieties were compared; mechanical separation which followed enzyme treatment did not result in complete separation of fibres and removal of lignin. Analogous to visual investigation, mechanical analysis of enzyme-treated hemp bast fibres also shows a wide scattering of measured values of tensile properties; correlating these results with observed fibre morphology, the inhomogeneity of fibre agglomerate diameters was recognised as on one of the main factors influencing the fibre fineness and their behaviour during tensile tests.
COBISS.SI-ID: 9134969
In plants, apical dominance prevents the development of lateral shoots. It can be overwhelmed by apical bud defoliation, allowing numerous lateral buds to develop into more lateral branches carrying more fruits and possibly increasing seed yield. This study tested this hypothesis on five hemp (Cannabis sativa L.) cultivars in a 2-year field experiment. In comparison to the intact ones, the defoliated plants developed several lateral shoots. The hemp seed yield was significantly influenced by the year of production, the apical bud removal, and the cultivar. The average twoyear seed yield of the defoliated plants (715 ± 47 kg/ha) was significantly higher than the yield of the intact plants (568 ± 35 kg/ha). Absolutely the greatest effect of apical bud removal on the seed yield was observed for the cultivar ‘Novosadska konoplja’, where increase was 225 kg/ha (25%); a slightly smaller difference occurred for the cultivar ‘Uniko-B’ (183 kg; 30%), followed by ‘Juso-11’ (140 kg/ha; 27%) and ‘Bialobrzeskie’ (128 kg/ha; 29). Cultivar ‘Beniko’ presented the smallest difference with apical bud removal – 58 kg/ha (15%) yield increase We maintain that hemp producers can achieve a larger seed yield not only by selecting an appropriate cultivar and row distance but also by removing apical buds.
COBISS.SI-ID: 9145209
Hemp has a wide applicability therefore there are many objectives of hemp breeding, e.g. higher fiber content in stem with increased quality, high seed yield with improved nutritional composition, specific cannabinoid profile, etc., but ?9-THC content below 0.2% is common to all old and new hemp varieties. Hemp is open-pollinated and dioecious plant with high genetic variability, what leads to many breeding problems, such as it needs to be maintained in isolation due to the strictly open pollinated plant species; the selection of male plants before flowering is difficult; cross-pollination among all cannabis plants exist and there is a lack of molecular breeding methods (e.g. marker-assisted selection). Despite all the obstacles, plant breeding is intensive in Europe, as evidenced by the increasing number of varieties listed on the Common catalogue of EU varieties. Breeding of hemp is caring on by using classical approaches, which are used for open-pollinated species, such as mass selection, cross-pollination, self-fertilization and hybrid breeding by crossing different varieties. In the future, breeders will be probably challenged by creation of varieties with the appropriate cannabinoid profile for medical use and cultivating such varieties through feminized seeds and obtaining hybrids from homozygous lines.
COBISS.SI-ID: 9387641
Hemp (Cannabis sativa) is as a potentially profitable alternative crop with a small share of cultivation land in the world. In its two decade's reintroduction in cultivation and processing in Slovenia has been accompanied by considerable technical barriers. Production practice varies widely in Slovenia and there is still a lot of manual work. The usual yield of seed is 300 to 600 kg/ha. However, in certain years, yields are much lower and in favourable conditions, up to one ton of seed can be achieved. Selection of the appropriate variety must have highest priority, since we have no Slovenian varieties at the moment. In the literature review, we found that hemp varieties can achieve extremely different yields of seed, stems and inflorescences and yields are highly year and location dependent. Field experiments in Slovenia showed that yields of seed, stem and inflorescences differ greatly among varieties. In Slovenia, 13 varieties are cultivated on areas larger than 10 ha. The cultivation area of varieties Fedora 17, USO 31 and Finola have been steadily decreasing since 2015, the cultivation area of the KC Dora is about 60 ha, while the area under the Tiborszallasi and Futura 75 varieties are increasing. These six varieties were grown on about 260 ha in 2018, which was 84 % of all hemp fields. In different geographical regions of Slovenia, growers give priority to different hemp varieties according to the purpose of cultivation for different end-uses.
COBISS.SI-ID: 9134201