Stalk rot caused by Fusarium fungi is one of the most widespread and devastating diseases of maize, and the introduction of resistant genotypes is one of the most effective strategies for controlling the disease. Breeding genotypes with genetically determined resistance will also allow less use of crop protection products. The aim of the research was to identify molecular markers and associated candidate genes determining maize plant resistance to Fusarium stalk rot. The plant material for the study consisted of 122 maize hybrids, which were sown in plots of 10 m2, in a complete randomized block design, in three repetitions, at two locations (Smolice: 51 42’ 58.904’’ N, 17 13’ 29.13’’ E and Kobierzyce: 50 58’ 19.411’’ N, 16 55’ 47.323’’ E). The analyzed genotypes were simultaneously subjected to next-generation sequencing using the Illumina platform. The results of the observation of the degree of infection and sequencing were used for association mapping, which ultimately resulted in the selection of 10 molecular markers important at both places. Among the identified markers, two SNP markers that are located inside candidate genes play an important role. Marker 4772836 is located inside the serine/threonine-protein kinase bsk3 gene, while marker 4765764 is located inside the histidine kinase 1 gene. Both genes can be associated with plant resistance to Fusarium stalk rot, and these genes can also be used in breeding programs to select resistant varieties.

The Spearman rank correlation coefficient is a non-parametric (distribution-free) rank statistic proposed by Charles Spearman as a measure of the strength of the relationship between two variables. It is a measure of a monotonic relationship that is used when the distribution of the data makes Pearson's correlation coefficient undesirable or misleading. The Spearman coefficient is not a measure of the linear relationship between two variables. It assesses how well an arbitrary monotonic function can describe the relationship between two variables, without making any assumptions about the frequency distribution of the variables. Unlike Pearson's product-moment (linear) correlation coefficient, it does not require the assumption that the relationship between variables is linear, nor does it require that the variables be measured on interval scales; it can be applied to variables measured at the ordinal level. The purpose of this study is to compare the values of Pearson's product-moment correlation coefficient (treating the data in a quantitative way) and Spearman's rank correlation coefficient (treating the same data in a somewhat "qualitative" way) and their statistical significance for six Pinus sylvestris L. traits (original – for Pearson's coefficient and ranked – for Spearman's coefficient) estimated from all observations, object means (for trees) and medians. The results show that the linear and rank correlation coefficients are consistent (as to direction and strength). In cases of divergence in the direction of correlation, the correlation coefficients were not statistically significant, which does not imply consistency in decision-making. Estimation of correlation coefficients based on medians is robust to outlier observations and factors that linear correlation is then very similar to rank correlation.

The growth of plant and process of yield formation in crops are moderated by surrounding conditions as well as interaction of genetic background of plants and environment. In the last two decades significant changes in climate can be observed generating unfavorable and harmful impact on plant development. Drought stress can be considered as one of the most dangerous environmental factor influencing plant life cycle and decreasing production of biomass and finally the yield. Plants can react to water deficit in a wide degree what is dependent on the species, the genetic variability within the species, the phase of the plant ontogenesis, the intensity of stress, and other potential stress factors. In plants there can be observed hybrids between distinct taxa which exhibit certain traits adopted to tolerate stress conditions better than parental plants. Oat × maize addition (OMA) plants are good example of fertile hybrids with retained maize chromosomes as addition to complete oat genome. Hybrids generated via wide crossing can exhibit morphological, physiological and biochemical variations implemented by the occurrence of extra chromosomes of maize, as well as interaction of maize and oat chromatin. The molecular analysis indicated 12.5% OMA lines among all tested descendants of wide oat-maize crossing. On the fourteenth day of the drought, a significant effect of stress on the content of soluble sugars and phenolic compounds was observed, soil drought significantly reduced plant biomass above ground and several yield components. Less water lost revealed by results of the excised leaf water loss test was correlated with high yield of OMA lines. Phenolic compounds content might be used as biochemical indicator of plant drought tolerance since there were significant correlation with high kernel yields of plants subjected to drought stress.