Valentina Usenik

Sweet Cherry Pomological and Biochemical Characteristics Influenced by Rootstock

Fruits of Lapins sweet cherry (Prunus avium L.) from 12-year-old trees on different rootstocks (F 12/1, Maxma 14, Piku 1, Edabriz, Gisela 5, Gisela 195/20, Weiroot 13, Weiroot 158, and Weiroot 72) were analyzed for pomological (fruit weight, % flesh of fruit weight, soluble solids content, titratable acidity, and firmness) and biochemical parameters (individual sugars, organic acids, and phenolic compounds) considering yield. For the first time, two procyanidins have been identified in sweet cherries using HPLC/MS: procyanidin B2 and procyanidin dimer (gamma(max) = 275 nm; [M - H](-) at m/z 577 and MS(2) fragments at m/z 425, 407, and 289). There were no significant differences between rootstocks in average yield per tree, except for Piku 1 (19.7 kg) with significantly the highest and Gisela 5 with significantly the lowest average yields per tree (7.7 kg). Significant differences in the measured parameters were ascertained among fruits of Lapins derived from different rootstock. Growing Lapins on Weiroot 72 and Edabriz resulted in high soluble solids content and fruit firmness. The lowest fruit firmness was measured on fruits from Weiroot 13, F 12/1, Gisela 195/20, and Maxma 14 trees. Fruits from Gisela 5 contained the lowest concentrations of glucose, fructose, sorbitol, sucrose, and citric acid, while fruits from F 12/1 contained the highest values of glucose, fructose, and shikimic acid. The content of phenolic compounds was the highest in fruits from Weiroot 72 tree, but the highest concentrations of procyanidin B2 and procyanidin dimer were ascertained in fruits from the Edabriz tree. Fruits from Weiroot 72 contained significantly higher concentration of phenols, bioactive compounds, compared to that in fruits from F 12/1. The content of individual and total anthocyanins did not differ significantly among rootstocks.

Flavonols of leaves in relation to apple scab resistance

Phenolic compounds of three scab-resistant apple cultivars ‘Topaz’, ‘Goldstar’ and ‘Gold Rush’ and two susceptible ones ‘Golden Delicious Weinsberg’ and ‘Golden Delicious Clone B’ were studied. The leaves were sampled four times in the period from 12 June to 10 September 2001. Flavonols rutin, quercitrin and ‘phenol 173’ (phenol with retention time 173,38 min) were analyzed using the Hplc system. Between the resistant and susceptible cultivars, statistically significant differences were established in the relative content of ‘phenol 173’, which was higher in the resistant cultivars during the growing season. It appears that the content is not affected either by different environmental conditions or by different stressors, but only by the genotype. Differences in the content of rutin and quercitrin were not significant. During the growth period, the content of phenolic compounds changed and was related to the physiological stage of the tissue and cultivar used.ZusammenfassungDie phenolischen Verbindungen in den drei gegen Schorf resistenten Apfelsorten ‘Topaz’, ‘Goldstar’ und ‘Gold Rush’ und in den zwei für Schorf anfälligen Sorten ‘Golden Delicious Weinsberg’ und ‘Golden Delicious Clone B’ wurden untersucht. Die Blätter für die Analyse wurden an vier verschiedenen Terminen zwischen dem 12. Juni und 10. September 2001 gesammelt. Die Flavonole Rutin und Quercitrin und ‘Phenole 173’ (Phenole mit der Retentionszeit 173,38 min) wurden mit Hilfe des Hplc bestimmt. Bei ‘Phenole 173’ konnten statistische Unterschiede gefunden werden. Die Gehalte dieser Substanz waren bei den resistenten Sorten während der ganzen Messperiode höher als bei den Standards. Sie wurden weder von verschiedenen Klimaverhältnissen noch von unterschiedlichen Stressfaktoren beeinflusst, sondern nur vom Genotyp. Die Gehaltsunterschiede bei den anderen Flavonolen ließen sich nicht absichern. Die Gehalte der phenol ischen Verbindungen veränderten sich in der Wachstumsperiode und waren vom physiologischen Status des Gewebes und von der Sorte abhängig.

Influence of foliar fertilization on yield quantity and quality of apple (Malus domestica borkh.)

The influence of foliar fertilization with Zn, B, P, Ca (Phosyn programmeme) on yield, quality and quantity was studied on cvs. ‘Elstar’, ‘Jonagold’ and ‘Golden Delicious’. Foliar fertilization improved the yield increase up to 30% and the share of the first class. The quality was determined by the contents of sugars (glucose, fructose and sucrose) and alcohol sugar sorbitol and organic acids (citric, malic, shikimic and fumaric) with HPLC (High Performance Liquid Chromatography) analyses and contents of mineral elements (Ca, K, Mg, N) in the fruits of apple trees. Contents of individual sugars and sorbitol of all cultivars were higher in Phosyn treatment than the control. Also, citric and malic acid contents were higher, whereas differences in shikimic and fumaric acids were less. Fruit mineral elements showed that foliar fertilization caused better quantities and relations among elements of individual cultivars and higher contents of soluble solids with regard to control treatment. Complex foliar fertilization had positive impact on quantity and quality of fruits at different cultivars of apple tree.

Sugars and organic acids in plum fruit affected by Plum pox virus

BACKGROUND Plum pox virus (PPV) causes severe economic losses in stone fruit production, but little is known about its effect on plum fruit composition. In this study, the influence of PPV on sugars and organic acids was evaluated in a susceptible plum (Prunus domestica L.) cultivar. RESULTS PPV infection significantly affected the content and composition of sugars and organic acids. The composition of necrotic tissue was modified the most. A short-time infected tree yielded fruit with similar sugar composition to fruit from a healthy tree, but the decline of organic acids was faster. Prematurely ripened symptomatic fruit had reduced fruit weight and low sugar content. CONCLUSION Infected trees of the studied cultivar produce fruit of inferior quality. Fruits are not suitable for processing, especially when most of them exhibit visual symptoms of PPV infection.