Five different rapeseed genotypes were tested. The following traits were considered: seed yield, seed germination, seed oil content, 1000 seed weight and seed protein content and they were used to determine whether there is significant or nonsignificant correlation. Highest average results were determined in genotype G-3 (yield 2.544 kg; germination 90%; 1000 seed weight 4,30 g; oil content 45,31% and protein content 19,83%) while G-5 (1.838 kg; 87%; 3,50 g; 44,77% and 17,28%) had the lowest average result of observed parameters. Highly significant positive correlations were found while comparing seed yield with 1000 seed weight (0.753**) and protein content (0.726**). High significant positive correlation were also determined comparing seed germination with 1000 seed weight (0.832**) and protein content (0.892**). Also high significant correlation was determined comparing 1000 seed weight and protein content (0.812**). Positive significant correlations were found by comparing seed yield and seed germination (0.644*). Path analysis indicated highest significant positive direct effect of 1000 seed weight (0.716**) and protein content (0.666**) on seed yield. High but negative significant value had seed germination (-0.645**). In the study of indirect effects on seed yield, none of significant effects were determined. The study of direct effects on oil content showed that the seed germination had high significant positive effect (-1.296**) on oil content. Significant but hot high effect has seed yield (0.556*). In other two traits it was determined negative high significant effects (1000 seed weight - 0.797** and protein content - 0.717**) on seed oil content. The existence of indirect significant effects on oil content in four cases was determined.

The trial in this study was carried out in field conditions throughout three years from plots where seed production of sunflower parental lines was established. Eight genotypes were examined; namely RHA-UK, RHA-ST-59, RHA-SES-IMI, RHA-SNRF, RHA-E-ANN-65, RHA-RU-3, RHA-CDN, and RHA-N-M-1. All the examined genotypes are parental components of the best sunflower hybrids developed by the Institute of Field and Vegetable Crops, Novi Sad, Serbia. Relationships between seed yield and eight different traits in sunflower were studied - oil and protein content, seed germination, 1000-seed weight, head diameter, number of branches and leaves and plant height. The same analyses were carried out for comparison of oil content. A highly significant positive correlation was determined between plant height and number of branches; plant height and the number of leaves; plant height and head diameter; plant height and seed yield; number of branches and yield; the number of leaves and yield; head diameter and seed yield; number of leaves and number of branches; number of leaves and head diameter and between seed germination and oil content. Path analysis indicated highest significant direct effect of plant height on yield (0.439**). The number of branches had a significant positive direct effect on yield (0.260*). In the study of indirect effects on yield, thirteen significant effects were determined. The study of direct effects on oil content showed that the plant height and number of leaves diameter had high significant effects (0.800** and -0.847**). The existence of indirect significant effects on oil content was determined in nine cases.

Maize is one of the most important field crops with broad genetic and phenotypic variations. It occupies an important place in agricultural production in the world as in Serbia. The main aim of maize breeding is to obtain new inbred lines, i.e. to identify new hybrid combinations that will surpass existing hybrids in terms of grain yield and other important traits. The aim of this study was to examine the phenotypic variability of 10 NS maize hybrids of different genetic bases and maturity groups in agroecological conditions in Rimski Šančevi, to consider the interdependence of grain yield and other tested traits using PCA and correlation analysis. The obtained results indicate a significant variation of all examined properties except for the ear length. The significance of the difference indicated by the F test was confirmed by the Duncan test. Correlation coefficients indicate a significant positive interdependence between the mass of 1000 grains and the ear length (r = 0.698). PCA analysis provided a more complex analysis of the interdependencies of the examined traits and grain yield. The highest yields were achieved by hybrids that simultaneously showed high values of several yield components. Yields ranged from 11,210 kg ha-1 in the G-10 hybrid (FAO 600), to 14,790 kg ha-1 in the G-3 hybrid (FAO 400). In this study, hybrids of earlier maturity achieved higher grain yields, mainly due to drought tolerance. Therefore, the goal is to create drought-tolerant maize hybrids that will successfully endure the negative consequences of global warming.

Summary As plant breeding is a very complex and sophisticated process, it is of paramount importance to understand the nature and magnitude of interdependence between specific plant features. Using PCA and correlation analysis, this study examined the variability in features of two types of inbred sunflower lines and determined its connection with their seed yields. The experiment was conducted as a randomized complete block design with four replications in Rimski Šančevi (the experimental field of the Institute of Field and Vegetable Crops in Novi Sad) in 2018 and 2019. It examined a total of nine inbred sunflower lines created at the Institute of Field and Vegetable Crops in Novi Sad. The results obtained suggest a high degree of variability in the examined traits of inbred sunflower lines considered, whereas the significance indicated by the F test was confirmed by the Duncan test performed. A high degree of variability was also found between the different types of inbred lines considered. A positive correlation was found between all four traits observed in the inbred sunflower lines considered, with different levels of significance. A statistically significant positive increase in the head diameter was followed by an increase in the weight of 1000 seeds, which generated a higher seed yield per unit area. According to the arrangement of different types of inbred lines considered on the PCA biplot, it can be concluded that the linoleic inbred lines G7L and G8L had the highest average values of the 1000-seed weight, head diameter and seed yield throughout the course of both experimental years. The useful data obtained by PCA analysis can facilitate successful selection programs aimed at developing sunflower genotypes that possess high stability and seed yields.

Climate changes inevitably affect plant production, but it is difficult to predict their direct impact on a vitality (germination) of a produced seed. Germination is the most important indicator of seed vitality and a key stage in the life cycle of plants. Seed germination is significantly affected by environmental factors during the growing season, as well as the method of processing (according to seed size). The aim of this work was to determine the impact of three factors on seed germination of four sunflower inbred lines: i) genotype, ii) environment conditions in a production year, and iii) seed size obtained during processing. The germination was examined in a standard laboratory test by ISTA Ruls, six months after the processing and natural breaking of dormancy. Larger and smaller sizes seeds, obtained in two consecutive years, which were characterized by different environmental conditions (sum of precipitation, mean monthly temperatures and air humidity during flowering), were used. Collected data was analyzed using a three-way analysis of variance, and correlation analysis. The coefficient of variation was 8.19%. Significantly higher average seed germination was obtained during 2020 (92%,) compared to 2021 (85%). The effect of seed size was not statistically significant, regardless of the tested inbred line. It can be concluded that the increase in the seed germination of sunflower inbred lines is mainly influenced by genotype, but also the increase in precipitation, minimum and maximum air humidity during flowering and the decrease in mean monthly temperatures, which was confirmed by the correlation coefficients between the above agroecological conditions and the germination rate of the produced seeds.