Aleš Vokurka

A Comparison of Fruit Chemical Characteristics of Two Wild Grown Rubus Species from Different Locations of Croatia

The main focus of our study was to investigate differences in nutritional (dry matter, soluble solids content, total acidity and pH value) and bioactive values (ascorbic acid, total anthocyanins, total phenols, and non-flavonoids content) of wild grown raspberry (Rubus idaeus) and blackberry (Rubus discolor) genotypes harvested from native populations in Croatia. The average total acidity ranged from 0.93 to 1.72% in R. discolor and 1.57 to 1.91% in R. idaeus. Ascorbic acid was found between 22.34 mg and 45.00 mg 100 g−1 in R. idaeus, while it was between 30.64 mg and 33.09 mg 100 g−1 in R. discolor genotypes. A great variability in total anthocyanins was detected in Croatian wild blackberry and raspberry genotypes, ranging from 2,226 to 2,367 mg kg−1 for blackberries and 279 to 582 mg kg−1 for raspberries, indicating wild blackberries are particularly rich in anthocyanins. On the basis of these results, it can be concluded that investigated wild growing fruit species have a great potential in nutritive research, as well as in biodiversity research. It is necessary to carry out further investigation and evaluation of wild growing fruit species to utilize them in the most appropriate way, as well as conservation of interesting accessions in the gene banks.

Morphological, genetic and phytochemical variation of the endemic Teucrium arduini L. (Lamiaceae)

Analysis of the morphological traits of leaves, genetic variability (analyzed by AFLP) and chemical composition of essential oils (analyzed by GC-MS) was conducted on eleven populations of the endemic Illyric-Balcanic species Teucrium arduini L. in Croatia, Bosnia and Herzegovina, and Montenegro. Average blade length and width ranged from 20.00 to 31.47mm and from 11.58 to 15.66mm, respectively. Multivariate analysis (PCA, UPGMA) of morphological traits distinguished two continental Bosnian populations from the remaining populations. AFLP analysis separated the investigated populations into two groups based primarily on geographical distance. Essential oil analysis showed a total of 52 compounds, with two chemotypes distinguished based on the essential oil profile. The first was a sesquiterpene chemotype, with β-caryophyllene, germacrene D or caryophyllene oxide as the major compounds, while the second was an oxygenated monoterpene chemotype, with pulegone and piperitone oxide as the main components. The Mantel test showed a stronger correlation between the morphological traits and AFLP than between the essential oil profile and AFLP. The test also showed a stronger association between the essential oil profile and geographical position than between the morphological traits and geographical position.

An Overview of Croatian Autochthonous Varieties of Sweet Cherry

Production of sweet cherry, both autochthonous and other, world known varieties, is mainly extensive, reduced to small orchards and gardens. There are just few intensive producers of sweet cherry whose production is set up according to contemporary production principles. However, interest for sweet cherry production is increasing and new producers are interested in growing autochthonous varieties. There are seven sweet cherry varieties known in Croatia. Their production is limited to certain geographic area where they are traditionally produced and where the production results in premium quality. These varieties are named according to toponyms of the region of their production (village, mountain or island). Due to the lack of pomologycal research of sweet cherry, there are few scientific data about these varieties. The question is even if these varieties are really native, or they might have been a result of non-controlled introduction hundred and more years ago, and spreading by given local names afterwards. This paper gives the description of autochthonous sweet cherry varieties according to IPGRI descriptors, estimates their potential in production and set up guidelines for further research of biodiversity in sweet cherries.

Soil assessment based on botanical composition on habitats of autochthonous populations of red clover (Trifolium pratense L.)

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.