Glucosinolates are the substituted esters of thio amino acids and their synthesis is based on the corresponding amino acids. Methionine and cysteine are the natural donors in the case of the Brassica plants and L-tryptophane in the indole glucosinolates, respectively. In Brassica genus, alkenyl glucosinolates are mostly present and their content and composition differ as far as the development stage and the part of the plant are concerned. The indole glucosinolates are present in a minority level. Their role of sulphur supply is questioned by their very low content between 2% in the beginning of vegetation and 0.1% in its end. Glucosinolates are discussed mostly from the aspect of their anti-nutrition, anti-microbial, anti-fungicidal, and anti-bacterial effects and as being natural bio-fumigants. Their decomposition products have the mentioned properties. The products originate by prepared passive protection by the two-component system. From the aspect of these properties, it is useful to divide them into the following three groups according to the characters of their decomposition products. The first group (I.), whose hydrolysis in the neutral and alkaline environment creates iso-thiocyanates. These bioactive compounds form the natural protection of the plant with bio-fumigatory effects particularly. Their anti-nutritive effects can be compensated by iodine, contrary to the second group (II.). This group is created by hydroxy-glucosinolates, whose decomposition products -iso-thio-cyanates -are not stable and they cycle while producing substituted 2-oxazolidinethione (goitrine -VTO). These glucosinolates represent a serious problem in feed industry since the VTO has a strong goitrogenic property. The third group (III.) -glucosinolates containing the indole group or the benzene ring (Sinalbin), create thio-cyanates during their hydrolysis. The role of indole glucosinolates has not been completely clarified so far. Their anti-carcinogenic effects are studied and they fulfil the role of an active protection.

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Glucosinolates with Brassica genus as secondary metabolites have a lot of functions and effects. Glucosinolates form less than 2% of the overall sulphur content at the beginning of vegetation in different parts of the plants and during growth their content is decreasing and forms less than 0.1%. This low representation doubts their storage function. With its chemical composition, they are ranked among natural pesticides with active and passive resistance against diseases and pests. They show repellent effects and properties of natural biofumigators in soil after ploughing in their biomass as green fertilizing, or after ploughing in after harvest the leftovers of rape. The principle of these effects is decomposition products of glucosinolates -bioactive isothiocyanates. Very important from this point of view are turnip rape Rex and Brassica juncea, whose content of these compounds is the highest one and they are resistant against the attack of Ceutorrhynchus pleurostigma. The same effect showed also when attacked by Phoma lingam. With other winter Brassicas either hybrid or linea and summer rape is this defensive system suppressed because of their lowered content due to breeding interferences, leading to limitation of their anti-nutritional negative effects. It is possible to state the final result after finding out the production of the above matter, roots, and after evaluation of the sorbal characteristics of the soil and evaluation of the state of health of the following crop or vegetable. After this overall analysis, it will be possible to evaluate the biofumigation properties of accessible varieties of the Brassica genus.

Three-year field trials were conducted to compare the effect of three tillage systems: strip-tillage (ST), strip-tillage after mouldboard ploughing (STmp) and conventional tillage (CT) on growth and yield of winter oilseed rape at the experimental station in Červený Újezd, Czech Republic. Compared to CT, the growth of roots and aboveground biomass was slower (significantly thinner root necks, shorter roots and leaves) under ST at the beginning of vegetation (BBCH 14–18). Plants under ST still had significantly thinner root necks, and a lower number of leaves than plants from CT before winter (BBCH 21) but the differences were no longer statistically significant in spring (BBCH 30). Despite a slower start, the ST variant with an average yield of 5.47 t/ha significantly exceeded the CT variant with the yield being 5.06 t/ha. Conversely, plants grown under STmp had significantly longer leaves than those under CT in BBCH 14–18 and with the highest values of all parameters, tended to faster growth of biomass, although the other differences were not statistically significant. No differences were observed between STmp and CT in BBCH 21 and 30. The STmp variant achieved the highest yield 5.53 t/ha, and significantly exceeded the CT variant.

The autumn growth and development was studied in three types of winter oilseed rape varieties (line, hybrid and genetically modified hybrid) at three technologies (intensity, standard and low input). Technologies were different by soil preparation before sowing, sowing rate, chemical treatment levels, growth regulation and fertilisation. It is evident from the autumn period 1999–2002, that the yield of biomass and roots in the autumn period was influenced by the technology and year conditions (water soil condition). The occurrence of surface soil clods influenced negatively the creation of root and aboveground biomass irrespective of the soil cultivation (ploughing or cultivation without ploughing). Also the excessive soil moisture negatively influenced the root and aboveground biomass and increased the differences among variants. The low input variant was substantially worse than intensity and standard. The dry mass of aboveground and root biomass was statistically different (alfa = 0.05) in the intensive and standard variant in comparison with the variant without ploughing (low input). No statistically significant differences were found in the mass of aboveground and root biomass (alfa = 0.05). The percentage of dry mass in aboveground and root biomass was statistically significantly higher (alfa = 0.05) in intensity of growth regulator application tebuconazole (Horizon 250EW) + chlormequat-chloride (Retacel Extra R68) compared with standard and low input. The diameter of root neck, length of roots and number of leaves was statistically the highest (alfa = 0.05) in the intensive variant. Statistically the values differed from the standard and low input variants. Substantially lower differences were found in the varieties in the same characters. GM hybrid showed a lower heterosis effect and the studied characters did not reach the level of unmodified hybrid level.