Linolenic acid content plays a significant role in the quality of oilseed rape oil. With the use of a model developed to calculate linolenic acid content depending on temperature, we performed simulations focused on the predicted changes of linolenic acid content triggered by expected climate change. The aim of the study was realized with the use of meteorological data recorded at 16 locations, representing 16 provinces in Poland, in the period of 1986–2005, and values obtained after the transformation of the recorded data to reflect temperature changes in four different representative concentration pathway scenarios (RCP2.6, RCP4.5, RCP6.0, RCP8.5) according to the gfdl_esm2m climate model. The results of the simulations performed under all tested scenarios (RCP2.6, RCP4.5, RCP6.0, RCP8.5) for all analyzed periods (2020–2039, 2040–2059, 2060–2079, 2080–2099) indicate a reduction of linolenic acid content as an effect of climate change. The comparison of simulation results obtained with and without allowing for the influence of temperature on oilseed rape development revealed the dominant role of direct influence in modifying the linolenic acid content. An analysis of the results also indicated how indirect influence of climate change, as expressed in changes of linolenic acid content generated by the acceleration of oilseed rape maturation, reduces the direct influence of climate change, expressed in changes of linolenic acid content caused by temperature. Additionally, simulation results point to opportunities, triggered by climate change, for a diversity of regions in terms of linolenic acid content in comparison to the years of 1986–2005.

Resynthesized (RS) Brassica napus can be used to increase the genetic diversity of this important crop plant and to develop the heterotic gene pool required for successful hybrid breeding programmes. The level of heterosis in F₁ hybrids depends on the individual performance of the parents and on the degree of genetic difference between them. However, RS forms obtained from crosses of B. rapa ssp. with B. oleracea ssp. possess many undesirable agronomic traits, such as low quality of seeds, low yield and seed oil content, high erucic acid level in the oil and high glucosinolate content in seed meal. Therefore, RS oilseed rape needs to be improved by crossing with natural double-low oilseed rape, leading to selected double-low quality semi-RS lines that can be used for breeding. In this study, we evaluated the seed yield potential of F₁ hybrids derived from crosses between Ogura cytoplasmic male-sterility (CMS) lines and doubled haploid (DH) semi-RS lines with restorer gene in three locations in Poland. The genotype by environment interaction (GE interaction) and general combining ability (GCA) of the restorer and CMS line effects, as well as the effects of heterosis, were also assessed. The results of the study provide the first insights into the use of semi-RS lines as components for the development of new hybrid cultivars. Even the introduction of 50% of the RS oilseed rape genotype to natural restorer lines resulted in a marked heterosis effect, with seed yield ranging from 4.56% to 90.17% more than that of the better parent. The yield of the best hybrid amounted to 108.6% of the seed yield of the open-pollinated cultivar Monolit and 94.4% of that of the hybrid cultivar Arsenal. The best DH semi-RS line S1, which had a significantly positive GCA for seed yield, can be recommended as a possible parent for inclusion in breeding programmes aimed at developing new hybrid cultivars.

Leaf rust caused by Puccinia recondita f. sp. tritici belongs to the most important diseases of wheat worldwide. The progress of the disease is highly dependent on meteorological conditions. One of the parameters affecting the disease progress is latency period driven mostly by temperature. Examination of the influence of predicted temperature changes on the monthly sum of the daily latency period expressed as rate (MSLPR) in western Poland was the aim of our study. Experiments in quasi-natural conditions were performed with the aim of validating models describing the influence of temperature on leaf rust latency period in two wheat varieties, Turnia and Ostroga. Both models used for assessment of latency period duration on cv. Turnia and cv. Ostroga performed well. The influence of climate changes on leaf rust latency period was then simulated using meteorological data from three weather stations located in western Poland and virtual data obtained after transformation of the recorded data to reflect a temperature changes under RCP2.6 and RCP8.5 scenarios according to giss_e2_r climate model. The study shows that without mitigation of greenhouse gas emission latency period of wheat leaf rust is going to decrease which may result in increase of wheat leaf rust incidence.

The Colorado potato beetle (Leptinotarsa decemlineata) is probably the most dangerous pest species of potatoes. This study assessed the influence of expected climate warming on the number of Colorado potato beetle generations in the Wielkopolska region of Poland using two simulation models, SimLep 1 and NumoGen 1. Two types of data sets were utilised in the simulations: real meteorological data recorded in Winna Góra (52.2N; 17.4E) in the period 2002–2011 and virtual data obtained after transformation of the real data to include an increase in the recorded temperature values between 1 and 6°C. The threat to potato crops from Colorado potato beetle was found to increase in response to expected climate change. A temperature increase of 2°C above that recorded during the last few years would allow the development of two full generations of the beetle, and further temperature increases may even permit the occurrence of three generations.

Disease development in plants is strongly dependent on weather conditions, with temperature playing a particularly significant role by influencing latency period duration. Using two models describing the relationship between latency period and temperature, we performed simulations aimed at predicting changes in the latency period of leaf rust (Puccina recondita f. sp. tritici) on triticale in response to expected climate change. The simulations were based on meteorological data recorded in the period 1986–2005 at locations representing 16 provinces in Poland and based on values obtained after transformation of the observed data to reflect temperature changes under four scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) according to the giss_e2_r climate model. In all scenarios, the results for the two triticale cultivars studied, Witon (vulnerable to P. recondita) and Gniewko (less susceptible), showed a threat of faster development (shorter leaf rust latency period) on triticale triggered by climate change in south-east and south-central Poland than in other regions. The results also showed an increased probability of future regional diversification of leaf rust latency period duration on vulnerable triticale cultivars, opportunities for earlier start of leaf rust epidemics on triticale in Poland and an increase in final disease severity in comparison with 1986–2005.

Effectiveness of Chemical Protection against Weeds Applied to Poppy (Papaver Somniferum L.): The aim of the presented studies was to determine the effect of chemical weed control on the development and yield of native poppy cultivars. The results of presented experiment showed that the native poppy cultivars are more susceptible to herbicides than ‘Opal’ and ‘Lazur’ cultivars. The yield of ‘Michałko’ cultivar in all treatments of chemical protection was very low. It was proved that the suggestion of a necessary protection of ‘Mieszko’ cultivar against weeds with lower doses of herbicides than the doses applied in the cultures of cultivars with a high content of morphine is justified. ‘Mieszko’ cultivar gave the highest yield on plots protected after sowing with Lentipur Flo™ 500 SC (a.s. chlorotoluron) in the dose of 1.2 l/ha and in the growth stage of 4 leaves, when the treatment was carried out with Callisto™ 100 SC (a.s. mesotrione) in the dose of 0.4 l/ha. Positive results of weed control after the application of these herbicides indicate the possibility to initiate studies aiming at authorization to use these herbicides in growing of the native cultivars of poppy (minor crop).