Arbuscular mycorrhizal fungi are the most widespread root fungal symbionts, forming associations with the vast majority of plant species. Ectomycorrhizal development alters gene expression in plant symbionts. In this work we examined the effect of arbuscular mycorrhizal fungi spores on the growth and development of Brassica and on the expression of BnMT2 in winter rape. In a pot experiment, rape seedlings growing on different types of sterile and nonsterile soils were inoculated simultaneously with mycorrhizal fungi spores of Acaulospora longula,Glomus geosporum, Glomus mosseae and Scutellospora calospora. As compared with control plants growing in the absence of spores, ten-week-old seedlings of Brassica napus L. in sterile soil inoculated with arbuscular spores had longer shoots and higher fresh biomass of above-ground plant parts. In other types of substrates enriched with mycorrhizal fungi spores, the plants were smaller than non-inoculated plants. The presence of AMF spores stimulated the elongation growth of hypocotyls in both analyzed substrates. BnMT2 expression was highest in plants growing on the sterile substrate. Generally, the presence of mycorrhizal fungi spores appeared to have an adverse effect on the growth of rape plants.

The objective of the present study was to identify the dynamics of Alternaria blight spread on spring oilseed rape lower, middle and upper leaves and siliques, to determine the disease incidence (DI) and severity (DS) on leaves, stems, siliques and seeds under the effect of prochloraz and tebuconazole. Efficiency of the fungicides was compared in relation to their application time. Field experiments with the spring oilseed rape cv. 'Star' were conducted at the Lithuanian Institute of Agriculture during 1997-1999.

Field surveys were performed in winter and spring rape crops of agricultural companies and individual farmers during the period of 2001–2003. A questionnaire was completed for each experimental field, giving a description of the crop. The incidence and severity of fungal diseases were estimated annually in 14–18 winter and spring rape crops. Seed samples were taken from each field and composition fungal communities on harvested seed was estimated. Alternaria blight and Phoma stem canker were present on stems of all investigated winter and spring rape cultivars and Alternaria blight occurred on siliques in all experimental years. In 2001, most favourable year for spread of diseases, Alternaria blight damaged 87.2 100% of winter rape and 100% of spring rape siliques, maximum disease severity was 6.66 and 7.24%, respectively. All cultivars of winter and spring rape were susceptible to Alternaria blight. Phoma stem canker was more often found on stems of spring oilseed rape – up to 98% of stems with symptoms of Phoma stem canker. Seed fungal infection level was 10.0–100% in winter rape and 16.0–93.6% in spring rape seed samples. The most frequent fungi on seeds of winter and spring oilseed rape were Alternaria spp. and Cladosporium spp.

Studies on palatability of some commom weed species, herbaceous plants and oilseed rape to D. reticulatum, A. lusitanicus and A. rufus slugs have been carried out under laboratory conditions. In food choice trials the rate and degree of damage to seedlings and leaf disks were determined for 20 plant species. The conducted experiments have also permitted to establish, which plant species were preferred or were not accepted by particular slug species. It was found that the studied slug species preferred seedlings and leaves of Brassica napus and Papaver rhoeas, but showed no preference for Epilobium hirsutum, Geranium sanguineum and Saponaria officinalis plants. As to the remaining plant species under study, the preferences exhibited by particular slug species were quite diverse.

Oilseed rape (Brassica napus L. ssp. oleifera Metzg) was the subject of the study in two forms: winter cv. 'Muller' (at the rosette stage - the first internode BBCH 30-31) and spring cv. `Feliks' (at the yellow bud stage BBCH 59). The main gas-exchange parameters, net photosynthetic rate (P-N) transpiration rate (E), stomatal conductance (g(s)), and intercellular CO2 concentration (Ci) were measured on leaves prior to the piercing and immediately after the short-term piercing. The effect of mechanical wounding revealed different progress of the gas exchange process for the two forms. Piecewise linear regression with the breakpoint estimation showed that the plants at the same age but at a different vegetal stage, manage mechanical leaf-piercing differently. The differences concerned the stomatal conductance and transpiration changes since for rosette leaves the process consisted of five intervals with a uniform direction, while for stem leaves-of five intervals with a fluctuating direction. These parameters got stabilized within a similar time (220 mins) for both forms. The process of net photosynthetic rate was altered by the plant stages. 'Muller' plants at the rosette stage demonstrated dependence of P-N on time in log-linear progression: y (P-N) = 8.01+ 2.73 log(10) (x t(2)); 7 < t(2) < 220; R-2 = 0.96. For stem leaves of Teliks' plants the process of transpiration, in terms of directions, was convergent with the process of photosynthesis. Those two processes were synchronized from 1st to 114th min of the test (r = 0.85; p < 0.001) in plants at the rosette stage and from 26th to 148th min in stem leaves (r = 0.95; p < 0.001).

Isozyme, RAPD and AFLP markers were evaluated and compared for their ability to determine genetic similarity in a set of 18 parental lines of winter oilseed rape F₁ hybrids developed using CMS ogura. Five isozyme systems, 64 RAPD starters and 23 EcoRI+3/MseI+3 AFLP primer combinations generated 597 polymorphic markers. These polymorphic fragments were chosen for estimation of genetic similarity. Of the total number of polymorphic products, polymorphic zymograms constituted only 3.0% of the markers, 57 RAPD primers 37.7%, and 23 AFLP primer combinations 59.3%. The size of RAPD polymorphic products ranged from 564 to 2100 bp. On average there were four amplified bands per primer, with 61.0% polymorphism. The AFLP polymorphic fragments ranged from 72 to 1352 bp in size. AFLP assays generated 15 bands per primer pair on average and detected roughly four times more bands than with RAPD analysis. The genetic similarity coefficients based on all marker data range from 0.52 to 0.84. The correlation of genetic similarities based on RAPD and AFLP markers was 0.58. Estimated genetic similarity based on isozyme data was not correlated with genetic similarity derived from the two DNA-based markers. The dendrogram constructed with the three types of markers taken together grouped all the winter oilseed rape parental lines into several similar clusters. The genomic distribution and frequency of the RAPD and AFLP markers can serve well as estimators of genetic similarity between parental lines of F₁ CMS ogura hybrids