Lidija Lenart

Microbiological quality and inhibitory potential of selected Croatian apiary honeys

The quality of honey is mainly determined by its sensorial, chemical, physical and microbiological properties. The purpose of this research was to evaluate microbiological properties of 72 honey samples and to determine the number and/or presence of aerobic mesophilic and spore-forming bacteria, moulds, yeasts, sulphite-reducing clostridia, bacteria from the Enterobacteriaceae family and Staphylococcus aureus. Microbiological quality of tested samples was considered good and pathogenic bacteria were not present. Inhibitory potential of selected honey samples was also investigated. Among tested honey concentrations (0.1%, 5%, 10%, 25%, 50% and 75%), the final concentration of 75% had the highest potential. Honeydew and chestnut honey exhibited the strongest inhibitory effect against tested bacterial species, while the lowest inhibition was exhibited by linden (lime tree) honey. Comparing the samples of the same honey type, considerably different inhibitory activity can be detected. Overall, the most sensitive bacterium to the inhibitory effect of tested honey samples was Staphylococcus aureus, while the most resistant one was Enterococcus faecalis.

Effect of genotype and environment on spring barley hordeins

One of the biggest challenges for the safe maize production is the yield stability in a wide range of environments with different soil fertility, weather conditions, prevailing pests and diseases as well as cultural practices. In order to achieve it, new hybrids with higher tolerance to biotic and abiotic stress are continuously being created. In order to compare performance of maize hybrids in environments with different levels and types of stress, and relate it to the stalk lodging incidence, we compared performance of 64 maize hybrids obtained by crossing 16 inbred lines with four inbred testers in three different environments. Two environments at same location (Rugvica) differed in crop rotation, and the third environment at location Botinec was considered as dry because of low water capacity of the soil. Mixed models that included all design elements and genetic background of hybrids were used to analyze the effect of lodging on yield in different environments. The results show that stalk lodging had a significant effect on yield, but significant lodging x environment interaction indicates that this effect was rather environment specific.Sweet pepper Istra F1 hybrid was grown in a greenhouse on K rich soil. For evaluation of K antagonism, two K rates (55 and 85 kg ha-1) were applied in a randomized complete block design with four replications. Total number of fruits, total number of BER affected fruits as well as average fruit mass were recorded for each harvest. Fruit and leaf K and Ca content were determined at three plant growth stages (at the stage of the first, third and fifth fruit cluster). Higher K rate gave higher : average fruit mass (169.45 g), total number of fruits per plant (7.95), number of BER affected fruits per plant (3.82), K in leaves (5.44% DM), K in fruits (6.35% DM), but negatively correlated with Ca concentration in fruits (0.57% DM) and leaves (3.24% DM). This resulted in decreased marketable yield of sweet pepper fruits.