Nebojsa Momirovic

Chemical composition of two different extracts of berries harvested in Serbia.

Total phenolic content (TPC), total anthocyanin content (TAC), free and total ellagic acid content, sugars, minerals, and radical-scavenging activity were determined in nine berries harvested in Serbia. More than 30 phenolic compounds were identified; among them, 11 polyphenols and cis,trans-abscisic acid were quantified using UHPLC coupled with an LTQ-Orbitrap XL mass analyzer. For the first time chrysin, naringenin, pinocembrin, and galangin were quantified in some of the investigated berry species. The extraction efficiency of the two extraction systems, methanol and acetone, was investigated. It was found that acetone is a better extracting solvent for TPC, whereas more TAC was extracted by methanol. TPC in acetone extracts ranged from 177.51 to 459.71 mg gallic acid equiv/100 g frozen weight. TAC ranged from 5.39 to 96.94 mg cyanidin-3-glucoside/100 g frozen weight in methanol extracts. The amounts of both free and total ellagic acid were found to be higher in the acetone extract in comparison to the methanol extract.

PRODUCTIVITY OF INTERCROPPING MAIZE (Zea mays L.) AND PUMPKINS (Cucurbita maxima Duch.) UNDER CONVENTIONAL VS. CONSERVATION FARMING SYSTEM

Abstract The evaluation of pumpkin (Cucurbita maxima Duch.) and maize (Zea mays L.) intercropping productivity, under different farming systems: conventional farming vs. conservation farming was carried out on the chernozem type of soil at Zemun Polje, Serbia. Results obtained by the bivariate analysis of variance showed significant differences between different proportions of components in intercropped maize and pumpkins. Regarding the land equivalent ratio (LER), two rows of pumpkins and two rows of maize (proportion 2/3:1/3) were the optimum spatial arrangement in conventional farming system, while proportion 1/3:2/3 was optimal in conservation farming system. The yield of pumpkins proportionally increased with the increase of the plant population, although the intraspecies competition of pumpkins was very pronounced in intercropping with maize. The average fruit yield of pumpkins in the first year was lower in conservation farming practices in comparison with conventional farming practices. On the other hand, situation was complete opposite with pumpkin yield in second year of investigation, while significant decrease in maize yield was observed in the plots where conservation farming practices were applied. Growing pumpkins in mixture with maize probably costs a small farmer very little more effort, than the production of a sole stand of maize. At least where the productivity of mixture is dominated by one species, as with maize in maize-pumpkins intercropping, the competitive effect of the recessive species on the dominant is small. Key words: Conventional farming; Conservation farming; Intercropping; Maize; Pumpkin