Phenology and fruit set of peach trees cultivated in Dois Vizinhos, Paraná State, Brazil

Understanding the dormancy phases and dynamics of commercial cultivars in the regions where they are grown allows for the implementation of different cultural practices and aids in the understanding of the temperature requirements for collaboration with genetic improvement programs. The objective of this study was to determine the budding, flowering, and fruit set rates of peach trees cultivated in the municipality of Dois Vizinhos, Southwestern Paraná, Brazil. The present work was developed using the collection of peach trees in the fruit growing sector of the Universidade Tecnológica Federal do Paraná. Sixteen peach cultivars were evaluated: Rubimel, Leonense, Coral, Marli, Charme, Riograndense, Douradão, Chimarrita, Granada, BR-1, Bonão, and Eldorado (all planted in 2009), as well as Regalo, Kampai, Fascínio, and Zilli (planted in 2014). The experimental design was completely randomized with four replications of one plant each, in a 16 × 2 bifactorial arrangement (cultivars × year/harvest). Phenology evaluations were performed weekly by counting open (anthesis) and sprouted flower buds, and the fruit set rate was measured just before fruit thinning. Flowering (%), budding (%), and fruit set (%) rates were calculated. It was found that the year/harvest 2016 promoted the highest rates of sprouting and fruit set. The Bonão cultivar showed greater flowering intensity and regularity in the crop years evaluated (2016 and 2017). Coral and Kampai present fruit sets with greater intensities and regularities when compared to the other cultivars evaluated under the climatic condition of the municipality of Dois Vizinhos. The Riograndense cultivar showed greater irregularity in flowering and fruit production.

PRELIMINARY RESULTS REGARDING THE FRUIT QUALITY AND YIELD OF SOME BLUEBERRY GENOTYPES

Vaccinium corymbosum is one of the berry species with economic and food interest to Romanian growers and consumers. The development of blueberrty crop is a result of breeding activity, which has generated many cultivars of quality fruit and high productivity. The characters that are of economic interest in the cultivation of blueberries depend on the area of cultivation where the new cultivars are obtained. The study was conducted in summer 2020 in an experimental plot established in 2015 with seven blueberry genotypes, at Research Institute for Fruit Growing, Pitesti, Romania in the Small Fruit Laboratory, having an experience in the field of more than 40 years. The objective at this study is to compare some of fruit characteristics from genotypes 'Azur', 'Delicia', 'Duke', 'Northblue', 'Simultan', '4/6' and '6/38': plant yield, average fruit weight, fruit length, fruit diameter, the soluble solids, fruit acidity or pH, fruit firmness. During this study 'Delicia' cv. proved to have the highest production per plant (4.20 kg plant), the highest values of fruit diameter (19.70 mm), and the highest value of fruit total titratable acidity (01.25 %).

Fruit and seed morphology in some representatives of the genus Malus Mill.

Aim. The study of morphological characteristics of fruits and seeds of the genus Malus is the key to the effective use of the apple genetic diversity in landscape-gardening, fruit growing, introductory and breeding. Methods. Morphological features of fruits and seeds of nine species and three varieties of apple (M. baccata, M. coronaria ‘Red Tip’, M. floribunda, M. fusca, M. halliana, M. niedzwetzkyana, M. × purpurea, M. × purpurea ‘Ola’, M. × purpurea ‘Royalty’, M. × purpurea ‘Selkirk’, M. trilobata, M. tschonoskii, M. toringoides) were studied. Generally accepted tech- niques of research was used. Results. The fruit weight of apple species and varieties varied from 0.30 g (M. fusca) to 61.20 g (M. coronaria ‘Red Tip’), the weight of 1000 seeds — from 5.00 g (M. fusca) to 62.77 g (M. coronaria ‘Red Tip’). The largest number of seeds in the fruit was characteristic of M. toringoides (6.64), the smallest — M. tschonoskii (0.25); developed seeds were not detected in the fruits of M. trilobata for 2019–2020 years. The lowest level of variability among biometric indicators of the studied representatives of the genus Malus was in terms of fruit height, fruit diameter and seed height, the highest — in terms fruit weight and number of seeds in the fruit. Conclusions. Detailed characteristics of fruits and seeds of the genus Malus, growing in the National Dendrological Park “Sofiyivka”, were compiled as a result of research. The obtained data can be used as a supplement to the botanical characteristic, and as a comparative material for taxonomy and phylogeny.

FRUIT QUALITY OF NEW INTRODUCED PLUM CULTIVARS UNDER THE CONDITIONS OF BULGARIA

Prunus domestica L. is one of the most commonly grown fruit species in Bulgaria due to its high ecological adaptation and multiple ways of fruit marketing. Fruit quality is associated with attributes such as appearance, texture, taste and colour. Breeding and new cvs. introduction are in constant search for cultivars with better fruit quality that would answer the increasing consumer requirements. In 2013 the Romanian plum cvs. ‘Pitestean’, ‘Roman’, ‘Romanta’, ‘Carpatin’ and ‘Tita’ were introduced in Bulgaria and planted in a collection orchard at the Fruit Growing Institute, Plovdiv. The study was conducted in the period 2016-2021. It aimed to evaluate the fruit quality when the cultivars are grown under the agro-environmental conditions of the region. For obtaining this objective, fruit weight, fruit flesh firmness, TSS (°Brix), skin colour with and without wax bloom and fruit flesh colour were measured. For evaluating consumer acceptance, a sensory analysis was performed. ‘Roman’ had the largest fruits with an average fruit weight of 46.66 g and the highest TSS content – 18.2°Brix. There were significant differences in the colour parameters L*, a*, b*, Chroma and Hue between the cultivars and the wax bloom had a significant effect on colour parameters. All fruits were appreciated by the testing panel of consumers and their taste qualities were evaluated as good and very good.

THE INFLUENCE OF DIFFERENT PHYTOPROTECTION SYSTEMS ON ENTOMOFAGE FAUNA IN APPLE PLANTATION

The paper presents data on the diversity of entomophagous fauna in an ecologically managed apple plantation, as well as aspects regarding the differences found in the structure of the entomophagous complex in three variants of phytoprotection technologies: "Ecological", "Biotechnical" and "Chemical standard". The study was carried out during the years 2019-2020, at the Research Institute for Fruit Growing Pitesti, in a plot aged 12 years. The evaluations were performed both in the field, visually and in the laboratory, at binocular magnifier. As a result of this study, a number of 6 species of predatory insects were identified: Chrysopa carnea, Coccinella septempunctata, Adalia decempunctata, Anthocoris sp., Phytoseiulus persimilis and Aphidoletes aphidimyza, were mainly from the Orders Mesostigmata, Coleoptera, Neuroptera, Diptera and Hemiptera.

MATING DISRUPTION OF GRAPHOLITA MOLESTA BUSCK. TO IMPROVE QUALITY AND HEALTHY OF PEACH FRUITS

In Bulgarian fruit growing agriculture mainly chemical plant protection is applied. Applications with organophosphates and pyrethroids are carried out to control the economically most important peach pest - the oriental fruit moth (Grapholita molesta Busck.). Annually during the vegetation season 7-8 insecticide treatments are applied. This leads to contamination of fruit products and the environment, which is a prerequisite for seeking other approaches. Regarding to fruit moth, sex pheromones are one of the most widely used environmental control methods, but they are most commonly used in apples. Their introduction in the monitoring of the main peach pest can lead to a reduction of chemical treatments and production with less pesticide residues. A promising direction is the use of pheromones to control the pests through sexual disorientation of males. The trial of mating disruption in the present study were carried out with ISOMATE® OFM TT dispensers in 0.9 ha peach orchard in 2020 and 2021. Pheromone traps type "Delta" of the Hungarian company CSALOMON® were used. The ISOMATE OFM TT dispensers, installed before the first flight of OFM at the rate of 250 units per ha, efficiently reduced fruit damages - down to 0.1-0.2% at harvest. In the reference orchard with 6 insecticide treatment against OFM, the damages reached 3.0-3.6%. The results indicate that mating disruption for control of Grapholita molesta Busck. can be used in production of quality and healthy peach fruits.

IN VITRO PROPAGATION OF PLUM ROOTSTOCK DOCERA 6

This paper describes research on the application of tissue culture techniques to the micropropagation of interspecific rootstock ʹDocera 6ʹ. The experimental work was carried out in the period 2017-2018, in the in vitro propagation laboratory of the Fruit Growing Institute Plovdiv. Аxillary buds were employed as initial explantеs in two different seasons (March-May; September-October). The action of the mineral medium was studied in the multiplication stage. The best result was obtained on LS medium included BAP 0.5 mg/l and IAA 0.05 mg/l. Тhe obtained average multiplication rate is 3.08. The concentration of auxin applied to the basal medium influence the quality of the root system Treatment with high concentrations of IBA added to the rooting medium gives the best results (V5). Тhe influence of the season on growth and development of micropropagated ʹDocera 6ʹ rootstock during ex vitro acclimatization is also part of our research. The spring acclimatization gives better results than the autumn.

ASSESSMENT OF APPLE FRUITS UNDER COLD STORAGE

The cold storage of fruits for a long period of time without quantitative and qualitative depreciations is absolutely necessary to supply the market with fresh fruits. This study aimed to investigate the changes in apple fruits during cold storage in order to determine their optimal storage capacity and to know the optimal moment of market sale. Five apple cvs. (‘Rumina’, ‘Rebra’, ‘Rustic’, ‘Generos’ and ‘Florina’) grown in the Genetics and Breeding Department of Research Institute for Fruit Growing Pitesti, Romania were kept in the cold storage at 2-4ºC and 90-95% humidity for 4 months. Before and after storage in cold conditions, the following physical and chemical parameters of fruits were evaluated: weight, color, firmness, soluble solids content and acids content. After 4 months, the fruits weight decreased with 2.45 g. The lowest weight loss was recorded on ‘Rumina’ cv. (1.48 g) and the highest for ‘Rebra’ cv. (3.20 g). At the end of storage period (January) the fruits firmness decreases with 7.74 Bareiss HPE-II FFF units, the best results being recorded on Rumina cv. (loss of firmness by only 5.23 units). Also, after cold storage the taste of the fruits was improved (the soluble solids content increased with 0.29 % Brix and the acid content decreased with 0.22 g/100 g fresh weight). The fruits color has changed gradually during the storage, the fruits being more colorful and attractive.

POMOLOGICAL CHARACTERISTICS OF LOCAL AND INTRODUCED WALNUT CULTIVARS IN SOUTH BULGARIA

A study of local and introduced walnut cultivars was carried out at the Fruit-Growing Institute – Plovdiv in the period 2018 – 2020. Four introduced walnut cultivars – two Romanian (‘Valmit’ and ‘Valeris’) and two Turkish (‘Şebin’ and ‘Yalova 1’) – and the standard Bulgarian cultivars ‘Izvor 10’ and ‘Silistrenski’ were the object of the study. Their vegetative habits were investigated and biometric measurements of the nuts were performed. Based on the results obtained the pomological characteristics of the studied cultivars were evaluated. When grown in the conditions of South Bulgaria, the cultivars introduced from Romania – ‘Valmit’ and ‘Valeris’ and from Turkey – ‘Yalova 1’, are characterized by very large nuts. ‘Izvor 10’ and ‘Şebin’ have a high kernel ratio.

RESOURCES FOR IMPROVING THE ASSORTMENT OF SWEET CHERRY VARIETIES IN BELARUS

The sweet cherry genetic collection of RUE "Institute of Fruit Growing" is including 273 accessions, which have been studied for the main economic and biological traits. The main features for selection are large-fruited combined with winter hardiness and resistance to cherry leaf spot. After an evaluation of the collection, three large-fruited accessions with tough pulp of the fruit were selected. The Ukrainian early fruit ripening variety ‘Annushka’ was selected among the introduced cherry varieties. This variety has large fruits of excellent taste and is characterized by high winter hardiness. Two Belarusian promising selections ‘84-10/98’ (‘Narodnaya’ o.p.) and ‘94-30/41’ (‘Vityaz’ × ‘Aelita’) were selected on these grounds. Selection ‘84-10/98’ has a medium and ‘94-30/41’ has late fruit ripening terms.