INFLUENCE OF SPRING FROST ON APPLE FLOWER BUDS AT VARIOUS DEVELOPMENTAL STAGES

Spring frost often reduces the yield because of damaged flowers. Spring frost is a dangerous climatic hazard that can be responsible for yield loses to orchard trees. Frost damage is highly dependent on the stage of development of the flower buds. Flowers buds samples were collected from ‘Granny Smith’, ‘Golden Delicious Rainders’ and ‘Gala Schniga’ apple cultivars at different flower buds stages from BBCH 59 (most flowers with petals forming a hollow ball) to BBCH 65 (full bloom on trees), two days after frost that occurred on the morning at 5:00-7:00 of March 31, 2017 when the temperature dropped to -1.5 to -3.3°C in the apple orchard of company Pollino Agrar near Fruška gora mountain. Pistils in flower buds samples at a hollow ball stage to full bloom were examined individually and classified as dead or alive based on tissue browning. The highest damage on flowers was recorded to cultivar ‘Gala Schniga’ (75.4%) and the lowest to cultivar ‘Golden Delicious Rainders’. Cultivar ‘Gala Schniga’ had more than 90% of damaged king flowers. Our results showed that the spring frost damage of pistils was variable according to stages of flower bud development and genotypes

CHEMICAL COMPOSITION OF HAZELNUT (CORYLUS SPP) CULTIVARS

Based on the results it was established that the fruits of all three tested varieties have less than 5% moisture. The dry matter content is over 95% which is several times higher than other fruit species. The high content of dry matter and low moisture content in the fruits of hazelnut allows much longer storage of the fruits of other species, with no changes and harmful consequences for the quality. Sugar content ranges between 4.91% (‘Tonda Gentile delle Langhe`) to 6.73% in (‘Roman hazelnut`). The protein content of examined cultivars is about 16%, and oil content as the majority of the organic matter in the fruits of the hazelnut was over 60%. Vegetable oils are mainly composed of unsaturated acids, oleic over 81% and 6% of linoleic and saturated, about 5% palmitic and stearic over 4%. Based on the above we can conclude that the fruits of hazelnut high-quality and essential in the diet, due to the significant roles they play in the human body. The aim of this study was to analyze the chemical composition of fruits of three major economic and most widespread cultivars of hazelnut in Serbia: 'Istrian long`, ‘Roman hazelnut` and ‘Tonda Gentile Delle Langhe`.Â

CHEMICAL COMPOSITION OFHAZELNUT (CORYLUS SPP) CULTIVARS

Based on the results it was established that the fruits of all three tested varieties have less than 5% moisture. The dry matter content is over 95% which is several times higher than other fruit species. The high content of dry matter and low moisture content in the fruits of hazelnut allows much longer storage of the fruits of other species, with no changes and harmful consequences for the quality.Sugar content ranges between 4.91% (‘Tonda Gentile delle Langhe’) to 6.73% in (‘Roman hazelnut’). The protein content of examined cultivars is about 16%, and oil content as the majority of the organic matter in the fruits of the hazelnut was over 60%. Vegetable oils are mainly composed of unsaturated acids, oleic over 81% and 6% of linoleic and saturated, about 5% palmitic and stearic over 4%.Based on the above we can conclude that the fruits of hazelnut high-quality and essential in the diet, due to the significant roles they play in the human body. The aim of this study was to analyze the chemical composition of fruits of three major economic and most widespread cultivars of hazelnut in Serbia: 'Istrian long’, ‘Roman hazelnut’ and ‘Tonda Gentile Delle Langhe’

ROOTSTOCK INFLUENCE ON VIGOR AND GENERATIVE POTENTIAL OF YOUNG SWEET CHERRY TREES

The main goal of breeding and testing of rootstocks for sweet cherry is to obtain small and productive trees and to improve precocity. The objective of this study was to examine the influence of six rootstocks on vigor and productive characteristics of young sweet cherry trees. The experimental orchard is situated at the Experimental farm “Radmilovac”, of the Faculty of Agriculture (near Belgrade). Three sweet cherry cultivars: ‘Kordia’, ‘Karmen’ and ‘Regina’ were grafted on six rootstocks: Prunus mahaleb L. seedlings, ‘Colt’, ‘Ma×Ma 14’, ‘Gisela 6’, ‘Gisela 5’ and ‘Oblačinska’ sour cherry. During a two-year period (2015-2016) the following characteristics were studied: scion diameter above the grafting union, rootstock diameter under the grafting union, length and diameter of shoots, height of the tree and the number of spurs per tree. The resultsshowed different influence of rootstocks on the tree vigor, spur formation and precocity. The average diameter of the scion in all tested cultivars was the largest on the Mahaleb rootstock. The largest average number of spurs per tree in the second year was recorded on cherry trees grafted on the rootstocks ‘Gisela 6’ and ‘Oblačinska’ sour cherry (28 and 23 respectively). The lowest average number of spurs (6) was found on trees grafted on the rootstock ‘Colt’