Pear Varieties Research Articles

The genus Crataegus (Rosaceae) in Armenia (an updated review)

The Rosaceae family plays a leading role in the dendroflora of Armenia. The Pyrus, Sorbus, Crataegus, Cotoneaster, Rubus and Rosa genera representing the family are of great importance in Armenia in the formation of various plant coexistences. With its species composition and taxonomic diversity, Crataegus is one of the largest genera in the Rosaceae family. Growing in Armenia in low, medium and high mountain zones, Crataegus has a great role in the formation of dendroflora: they are an important element of a number of forest coexistences, form a sub-forest with other representatives of dendroflora, grow in arid sparse forests, scrub, shoreline areas of mountain rivers. Crataegus is a valuable plant resource. Some species produce tasty and nutritious fruits that are rich in sugars, organic acids, mineral salts and vitamins. Since ancient times, the people of Armenia have used it in food and folk medicine, for example there is a decoction of hawthorn root and bark dyed threads. Currently, Crataegus has great economic importance. Drought-resistant and frost-resistant species are used as grafts for obtaining high-value varieties of apple, pear, and quince, decorative species are suitable for greening cities and settlements, creating living fences. Furniture and carpentry tools are made from its hard and strong natural wood. Due to their hardiness, some species of Crataegus are promising for the creation of arid arboretums in the lower and middle mountain zones of Armenia. In Armenia the genus Crataegus is represented by 23 species belonging to three sections: Crataegus, Pentagynae C. K. Schneid. and Azaroli Loud. Species C. ulotricha Pojark. ex Gladkova, C. razdanica Pojark. ex Sargsyan, C. gabrielianae Pojark. ex Sargsyan, C. susanykleinae Gabrieljan et Sargsyan and C. gregorianii Gabrielian et Sargsyan are endemic to Armenia. An updated key is provided to identify species based on new data. Altitudinal and geographical distribution of species, habitat, flowering and fruiting time are given.

RESISTANCE OF FRUIT CROPS VARIETIES TO PHYTOPATHOGENIC
 BACTERIA PSEUDOMONAS SYRINGAE PV. SYRINGAE

The resistance of cherry, sweet cherry and pear varieties to bacterial canker was analyzed by using the method of arti-
 ficial contamination of unripe fruits. Two resistance groups were highlighted among the six analyzed cherry varieties:
 Uyfehertosh Fürthosh variety exercised the highest degree of resistance and Turgenevka exercised the lowest degree. Three
 groups of resistance were identified among the ten studied varieties of sweet cherries; the cultivar Lyubava Donetskaya turned out to be the most resistant, Gascinets proved to be the most affected. Four groups of resistance were distinguished among analyzed 14 pear varieties. The most resistant was Vilia variety and Kudesnitsa variety turned out to be the most affected.
 None of the examined crops varieties appears to be immune to bacterial canker. After artificial contamination of apples fruits
 (Belorusskoe sladkoe, Kovalenkovskoe and Nadzejny varieties) symptoms of the disease did not appear.

RUST (GYMNOSPORANGIUM SABINAE (DICKS.) G. WINTER) RESISTANCE OF PEAR VARIETIES RELEASED IN BELARUS

The article presents preliminary results of an assessment of field resistance to rust (Gymnosporangium sabinae (Dicks.) G. Winter) of 27 pear varieties released in Belarus. The studies were conducted in 2017–2021 at RUE “Institute of Fruit Growing”. Differentiation of pear varieties according to the degree of rust resistance was revealed: highly resistant (Dessert Rossoshanskaya, Pamiati Yakovlev), medium resistant (Bere Loshitskaya, Viliya, etc.), low resistant (Bere Alexander Luka, Velesa, Duchesse summer, Conference, etc.) and very low resistant (Belarusian late).

Anti-hail Net in Korla Fragrant Pear Planting

Korla fragrant pear is the main pear variety and one of the most famous fruits in Southern Xinjiang. The use of protective nets in fruit tree production is increasing; however, the cultivation of Korla fragrant pear in Xinjiang has yet to be developed. Therefore, we used the ground and underground microclimate anti-hail network and open-air conditions to determine the fruit quality and measure tree growth-related indicators. Additionally, we subsequently recorded the average yield of fragrant pear fruits to evaluate their economic value under the anti-hail net and open-air environments. Furthermore, we performed a correlation analysis to explore the correlation between environmental factors and fruit quality and growth under the two conditions. We found that the anti-hail net cover provided a conducive environment for the vegetative and reproductive growth of trees. Under similar fruit quality conditions, the average yield was markedly higher under the anti-hail net environment than under the open-air environment. Furthermore, the economic benefit under the anti-hail net was higher for all factors, except for the average facility cost during the previous year, than that under the open-air condition.

Simulation Parameter Calibration and Test of Typical Pear Varieties Based on Discrete Element Method

To improve the accuracy of discrete element simulation parameters for the mechanized picking and collection of pears, the study calibrated the simulation parameters of pears by the method of combining a physical experiment and simulation. Based on the intrinsic parameters of four kinds of pears (Snow pears, Crisp pears, Huangguan pears and Qiuyue pears), their simulation models were constructed by the Hertz-Mindlin with a bonding model. The simulation parameters between pears and the contact material (PVC, EVA foam material) were calibrated by the methods of free fall collision, inclined sliding and rolling, respectively. The experiments of pear accumulation angle were carried out. It was obtained to process the image of pears with Matrix Laboratory software. In order to determine the optimal value interval of influencing factors of the pear accumulation angle, the steepest ascent experiment was carried out. Considering the coefficient of collision recovery, the coefficient of static friction and the coefficient of rolling friction between pears, five-level simulation experiments of the pear accumulation angle were designed for each factor by the method of orthogonal rotation combination. The regression model of the error between the measured value and the simulated value of the pear accumulation angle was established, and the influence of three factors on the pear accumulation angle was analyzed. The results showed that the static friction coefficient and rolling friction coefficient between pears have significant effects on the pear accumulation angle. Therefore, the optimal model of minimum error was constructed according to constraint condition, and the coefficient of collision recovery, coefficient of static friction and coefficient of rolling friction between pears were obtained. The accumulation angle verification experiments were carried out by the method of bottomless barrel lifting. The results showed that the relative error between the simulated and measured accumulation angle of four kinds of pears were 1.42%, 1.68%, 2.19% and 1.83%, respectively, which indicated that the calibrated simulation parameters were reliable. The research can provide a basis for the design and parameters optimization of harvesting machinery of pears.

Nutmeg pears in the Middle Volga region

The aim of the study was to breed highly adaptive pear varieties that combine high ripeness, nutmeg flavor, as well as long-term fruit keeping during storage. In the Research Institute of Horticulture and Medicinal Plants «Zhigulevskie Sady», work on breeding pear varieties with nutmeg flavor was started by S. P. Kedrin in 1934 with the use of the Williams summer variety in breeding work, and later in 1985, this breeding work with the use of qualitative characteristics of the Williams red variety as a donor the work was continued by A. A. Kuznetsov in order to obtain varieties of pears with a nutmeg flavor. In addition to obtaining varieties with the desired taste qualities, the breeding work of the Institute is aimed at obtaining varieties with high adoptive qualities for use as a garden crop in the conditions of the Middle Volga region. In 2021, the Yakhontovaya variety (Volozhka x Williams red) bred at the institute is included in the State Register for the 7th region. The article also provides a brief description of 4 promising varieties of pears with nutmeg flavor well adapted to local conditions. Three varieties: Dar Zhiguley, Muskatka, Yakhontovaya were obtained as a result of distant crosses with the participation of the Ussuri pear (P. ussuriensis M.), and the fourth variety Volshebnitsa is an intervarietal hybrid. All of them belong to the group of early-fruiting varieties. A long period of fruit consumption (1.5-2 months) was observed in Muskatka and Dar Zhiguley varieties. The Yakhontovaya variety has high commodity and consumer qualities. The varieties have a complex of biologically and economically valuable traits and can be used in breeding. The creation of pear varieties with high-quality fruits capable of competing with foreign ones seems to be quite a possible task for breeders.

Induction and identification of tetraploids of pear plants (Pyrus bretschneideri and Pyrus betulaefolia)

Polyploid plants usually exhibit broader leaves, thicker stems, bigger flowers and fruits, dwarfing stature, as well as improved biotic and abiotic resistance. Therefore, increasing the polyploidy is one of the most important strategies used in plant breeding. Here, we reported the successful induction of tetraploids of two pear varieties, ‘duli’ pear (Pyrus betulaefolia), a wildtype pear used for rootstocks in grafting, and ‘Xinli No.7′ pear (Pyrus bretschneideri), a popular cultivated pear variety in China. This was achieved by treating their seeds, shoot tips of tissue cultured or field grown seedlings with colchicine and pendimethalin using three different methods: impregnation, mixed culture and smearing. The best tetraploids induction condition for ‘duli’ pear seeds was impregnating them with 0.4% colchicine for 24 h where the mutation rate of 2.0% was achieved with no chimera found. For shoot tips of tissue cultured seedlings the best condition was impregnating them with 0.2% colchicine where 6.67% of ‘duli’ (48 h) and 13.0% of ‘Xinli No.7′ (24 h) were mutated. In addition, we found that in the mixed culture method the best induction condition for ‘duli’ was mixing with 1.0% colchicine while for ‘Xinli No.7′ it was 0.5% colchicine. In the smear method, for the shoot tips of field grown seedlings of ‘duli’, the best induction condition was treating them with 0.4% colchicine for 24 h. Subsequently, the DNA content of these putative polyploid seedlings was estimated by the flow cytometry, confirming their ploidy nature. Also, we compared the morphological differences between the tetraploid seedlings and the diploid seedlings. Obviously, the tetraploid seedlings appeared to be dwarfed with shorter internode length and reduced internode number of their stems.

Impact of paclobutrazol on gibberellin-like substances and soluble carbohydrates in pear trees grown in tropical semiarid

Given that Brazilian pear production is unable to meet the annual demand, to consider the possible expansion to non traditional growing regions, turns interesting. Even though under tropical semi-arid conditions pear trees have vigorous vegetative growth, a negative influence on flower bud differentiation and formation affects fruit yield. Our study aimed to evaluate the inhibition efficiency of paclobutrazol (PBZ) on gibberellin biosynthesis, vegetative growth, and carbohydrate production in two pear-treecultivars (‘Santa Maria’ and ‘Hosui’) grown under semi-arid conditions. To this end, two experiments were conducted, one for each pear-tree cultivar. The experimental designs consisted of randomized blocks, with factorial arrangement (5x2x4), corresponding to PBZ doses (0.0, 0.5, 1.0, 1.5, and 2.0 g per linear meter of plant canopy), PBZ application forms (soil and foliar), and evaluation dates (30, 60, 90, and 120 days after application). Both soil and foliar applications inhibited gibberellin biosynthesis in both cultivars, especially after 120 days of application. PBZ affected leaf total soluble carbohydrates and reduced sprout growth in both cultivars. Although PBZ can be potentially used in pear management, further studies are still required to determine specific management practices in tropical semi-arid zones. Highlights: Inhibition of gibberellin biosynthesis is more efficient with soil application of paclobutrazol. Soil application of paclobutrazol results in greater production of carbohydrates. There is a difference in sensitivity to the effects of paclobutrazol among pear varieties. The non-application of paclobutrazol results in late maturation of the branches, compromising floral induction.

The Microbiome of the 'Williams' Pear Variety Grown in the Organic Orchard and Antifungal Activity by the Autochthonous Bacterial and Yeast Isolates.

The total diversity of bacterial and fungal communities associated with the phyllosphere (fruits and leaves) of the ‘Williams’ pear variety was analyzed in two phenological stages during fruit development and maturation. The antagonistic potential of autochthonous bacterial and yeast isolates against phytopathogenic fungi was also evaluated. A metabarcoding approach revealed Pantoea, Sphingomonas, Hymenobacter, Massilia, and Pseudomonas as dominant bacterial constituents of the pear phyllosphere, whilst most abundant among the fungal representatives identified were Metschnikowia, Filobasidium, Aureobasidium pullulans, Botrytis cinerea, and Taphrina. The traditional culturable approach revealed that the Pseudomonas genus with P. graminis, P. putida, and P. congelans was most prevalent. The most frequently cultivated fungal representatives belonged to the genus Fusarium with six identified species. A broad range of the antagonistic activity was detected for the Hannaella luteola and Metschnikowia pulcherrima yeasts, significantly affecting the growth of many fungal isolates in the range of 53–70%. Fusarium sporotrichioides was the most susceptible fungal isolate. The autochthonous antagonistic yeasts H. luteola and M. pulcherrima might be powerful biological control agents of postharvest diseases caused by Fusarium spp. and common pathogens like Monilinia laxa, Botrytis cinerea, Alternaria tenuissima, and Cladosporium cladosporioides.

Genome-Wide Identification of Genes Encoding for Rho-Related Proteins in 'Duli' Pear (Pyrus betulifolia Bunge) and Their Expression Analysis in Response to Abiotic Stress.

Twelve Rho-related proteins (ROPs), namely PbROPs, were identified from the genome of the recently sequenced ‘Duli’ pear (Pyrus betulifolia Bunge), a wild-type pear variety routinely used for rootstocks in grafting in China. The length and molecular weight of these proteins are between 175 and 215 amino acids and 19.46 and 23.45 kDa, respectively. The 12 PbROPs are distributed on 8 of the 17 chromosomes, where chromosome 15 has the highest number of 3 PbROPs. Analysis of the deduced protein sequences showed that they are relatively conserved and all have the G domain, insertion sequence, and HVR motif. The expression profiles were monitored by quantitative RT-PCR, which showed that these 12 PbROP genes were ubiquitously expressed, indicating their involvement in growth and development throughout the life cycle of ‘Duli’ pear. However, they were altered upon treatments with abscisic acid (ABA, mimicking abiotic stress), polyethylene glycol (PEG, mimicking drought), and sodium chloride (NaCl, mimicking salt) to tissue-cultured seedlings. Further, transgenic Arabidopsis expressing PbROP1, PbROP2, and PbROP9 exhibited enhanced sensitivity to ABA, demonstrating that these 3 PbROPs may play important roles in the abiotic stress of ‘Duli’ pear. The combined results showed that the ‘Duli’ genome encodes 12 typical ROPs and they appeared to play important roles in growth, development, and abiotic stress. These preliminary data may guide future research into the molecular mechanisms of these 12 PbROPs and their utility in molecular breeding for abiotic stress-resistant ‘Duli’ pear rootstocks.

Effects of Different Pollination Combinations on Stone Cells, Lignin, and Related Enzyme Activities in Fragrant Pear Fruit

In this study, the effects of different Xinjiang pear varieties and ‘Korla Fragrant Pear’ pollination on the stone cells and lignin of fruit were investigated. The contents of stone cells and lignin, and the activities of related enzymes [polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonium lyase (PAL)] were analyzed in fruit from different pollination combinations at different growth and developmental stages. Results showed that the stone cell mass density decreased rapidly at 60 to 90 days and 90 to 120 days after flowering. The stone cell and lignin contents, and activities of the three enzymes (PPO, POD, and PAL) decreased rapidly at 60 days after flowering. The stone cell mass density, stone cell and lignin contents, and enzyme activity of fruit from different pollination combinations varied at different timescales. The pear variety ‘Bayue‘ had the lowest stone cell and lignin contents in mature fruit from different pollination combinations. The stone cell content correlated positively with lignin content, stone cell mass density, and enzyme activity.

Peculiarities of the phenological phases of the development of pear varieties in the conditions of the steppe zone of the Southern Urals

The article presents the results of long-term studies of the peculiarities of the phenological phases of the development of promising pear varieties of domestic breeding in the conditions of the steppe zone of the Southern Urals (Orenburg region). The research was carried out in 2018-2021 at the experimental site of the 2002 laying of the Orenburg branch of the Federal Research Center of Horticulture. The objects of research were varieties of pears of domestic breeding Krasnobokaya (st), Skazochnaya, Pingvin, Permyachka, Sverdlovchanka, Isetskaya sochnaya, Lel, Chizhovskaya, Lada, Vidnaya, Povislaya (st), Gvidon, Uralochka, Samarskaya krasavitsa, Pamyat of Parshin. The calculation of phenological atypicity to identify the correspondence of the phases of development of pear varieties to the conditions of the region was carried out according to the method of Zaitsev G. N. Statistical processing of the obtained data was carried out in accordance with the methodological recommendations of Zaitsev G. N. and Dospekhov B. A. using the Microsoft Office Excel 10 analysis package. It was established that the studied varieties are characterized by a short growing season — 160-170 days; the required amount of active heat is on average 3 158.9 °C. For pear varieties, the timing of the onset of phenological phases is determined by the accumulated sum of positive temperatures: the beginning of vegetation — 200-304.7 °C; the beginning of flowering – 354-476.6 °C; removable fruit maturity — 2 504-3 603 °C; the end of leaf fall — 3 1793-666 °C. It was found that the timing of the onset of the phenological phases of the beginning of vegetation, the beginning and end of flowering, the end of shoot growth, as well as the duration of flowering periods, shoot growth and vegetation depend more on the conditions of the year than on the genotype. The removable maturity of fruits, the duration of the interphase period, the formation and growth of fruits are determined by characteristics of the variety. The assessment of phenological atypicity revealed that all the studied varieties are in the optimum for the realization of their phenological phases of development.

Phenotype and mechanism analysis of plant dwarfing in pear regulated by abscisic acid

Close planting of dwarf varieties is currently the main cultivation direction for pear trees, and the screening of excellent dwarf varieties is an important goal for breeders. In this study, the dwarfing pear variety ‘601D’ and its vigorous mutant ‘601T’ were used to show their biological characteristics and further explore the dwarfing mechanism in ‘601D’. The biological characteristics showed that ‘601D’ had a shorter internode length, a shorter and more compact tree body, thicker and broader leaves, lower stomata density, larger stomata size (dimension), and higher photosynthetic capacity. The biological characteristics of ‘601T’ showed notable contrasts. The results of endogenous hormone tests indicated that the contents of abscisic acid (ABA), ABA-glucosyl ester, and GA4 were higher in ‘601D’, but the trans-zeatin content was lower. By transcriptomic analysis, significant differences were found in the biosynthetic and metabolic pathways of ABA. Related transcription factors such as bHLH, WRKY, and homeobox also participated in the regulation of plant dwarfing. We therefore examined three hormones with obvious differences with ‘601T’, and found that only ABA could induce ‘601T’ to return to a dwarfing plant phenotype. Therefore, we conclude that the dwarfing of ‘601D’ is caused by an excessive accumulation of ABA. This study provides a new theoretical basis for breeding dwarf varieties.

Comparative transcriptome analysis of candidate genes involved in chlorogenic acid biosynthesis during fruit development in three pear varieties of Xinjiang Uygur Autonomous Region.

Pear is one of the main fruits with thousands of years of cultivation history in China. There are more than 2000 varieties of pear cultivars around the world, including more than 1200 varieties or cultivars in China (Legrand et al., 2016). Xinjiang Uygur Autonomous Region is an important pear production region in China with 30 of varieties or cultivars. Pyrus sinkiangensis is the most popular variety, which is mainly distributed in Xinjiang (Zhou et al., 2018). Chlorogenic acid (CGA), p-coumaric acid, and arbutin are the main polyphenols in pear fruit, and their levels show great differences among different varieties (Li et al., 2014). CGA is a potential chemo-preventive agent, which possesses many important bioactivities including antioxidant, diabetes attenuating, and anti-obesity (Wang et al., 2021). Therefore, the specific CGA content of a variety is considered the embodiment of the functional nutritional value of pears.

Performance analysis of pear varieties of the Urals selection

The fruiting behaviour of eight pear varieties of the Urals selection was studied: Tonkovetka Uralskaya, Nizkoroslaya, Talitsa, Zarechnaya, Permyachka, Gvidon, Dobryanka, Raduzhnaya; Polya was used as a reference. The research was carried out in 1992-2020. All examined varieties began fruiting at the age of 5-6 years; heavy bearing was achieved at the age of 7-13 years. The early maturity of the Gvidon variety was singled out, in which heavy bearing occurred at the age of 7 years and annually exceeded the reference variety by the total yield at a young age (6-12 years). The Gvidon, Raduzhnaya and Zarechnaya varieties showed statistically significantly higher yields at the age of 13-29 years (21.1-27.9 t/ha) than the reference variety; the Talitsa variety demonstrated similar yields to those of the reference (17.3 t/ha). The Tonkovetka, Uralskaya, Permyachka, Dobryanka and Nizkoroslaya varieties exhibited moderate yields (10.0-13.1 t/ha). In the Polya (k), Gvidon, Zarechnaya, Talitsa, Tonkovetka Uralskaya, Permyachka, Dobryanka, Nizkoroslaya varieties, positive dynamics was observed up to 15-19 years, in the Raduzhnaya variety — up to 20-24 years. The maximum growth rate in yield was reported for all varieties at 10-14 years. The Gvidon and Raduzhnaya varieties comprise high-yielding, regularly fruiting, with a medium stable yield; the Zarechnaya variety represents high-yielding with irregular fruiting. The Talitsa variety constitutes a high-yielding variety with irregular fruiting. The Tonkovetka Uralskaya and Permyachka varieties are medium-yielding with medium stable fruiting. The Dobryanka and Nizkoroslaya varieties are medium-yielding with irregular fruiting.

Heat resistance of pear plants during recovery from latent viruses using dry-air thermotherapy

The dry-air thermotherapy for fruit and berry crop recovery from harmful viruses has become a widely used technology. The method allows virus-free plants to be obtained within one year. The present work examines the heat resistance of pear plants during the recovery from major harmful viruses using dry-air thermotherapy. The method was employed on the pear plants of Belorusskaya Pozdnyaya, Bryanskaya Belitsa, Velesa, Letnyaya Zabava, Zolotoy Vityaz, Aurora, Gera, Chizhovskaya varieties, R-11-9, R-10-3, R-2-4 hybrids and Zagoryevskii rootstock in 2020-2021 at a temperature of 38 °C for 90 days. The recovery was carried out against harmful latent viruses of apple-tree stem pitting (ASGV), apple brown spot (ASPV), chlorosis (ACLSV), apple mosaic virus (ApMV). For thermotherapy, a temperature chamber designed at the FSBO ARHCBAN, having a temperature gradient for root and elevated systems, drip watering, illumination by LED fixtures, was used. The transpiration rate, leaf water content, water loss, water deficiency and recovery of water content were determined. The plant growth parameters of different pear varieties depended on the duration of thermotherapy and varietal features. The Velesa, Zolotoy Vityaz varieties and Zagoryevskii rootstock generated the longest shoots. As compared with winter greenhouse conditions, the transpiration rate decreased 2.1 times, the total water content in leaves increased 1.5 times, the water loss upon heat shock decreased 1.6 times, and the recovery of water content increased 1.8 times. The Bryanskaya Krasavitsa varieties and R-11-9 and R-10-3 hybrids exhibited the highest heat resistance during cultivation in a heat chamber; the Letnyaya Zabava and Zolotoy Vityaz varieties exhibited medium heat resistance; the Belorusskaya Pozdnyaya variety, R-2-4 hybrid and Zagoryevskii rootstock were characterised by low heat resistance. A high positive correlation (r = 0,92) between total water content in leaves and the recovery of water content following heat shock was established. The yield of ASGV, ASPV, ACLSV, ApMV virus-free pear plants in the year following dry-air heat treatment amounted to 83 %.

Identification and characterization of a stem canker and twig dieback disease of pear caused by Neofusicoccum parvum in Chinese mainland

Pear (Pyrus spp.) is one of the most consumed fruits in China, but the pear production has to confront the growing threat from fatal diseases. In this study, we report two incidences of stem canker and twig dieback disease on pear plants, which led to death of pear seedlings (approximately 10% of total plants) in Guangxi and Jiangsu provinces. Using a combination of morphological and molecular diagnoses, along with pathogenicity test, the causal agent of the disease in these two locations was identified to be the fungus Neofusicoccum parvum. However, the isolates were divided into two clades: CY-2 isolate and other four isolates including ZL-4, BM-9, BM-10 and BM-12 might split into two groups of N. parvum. Two representative isolates (CY-2 and ZL-4) were selected for further investigation. We observed that the optimal temperature for in vitro infection on pear trees of these two isolates was at round 25 °C. Both CY-2 and ZL-4 could infect different sand pear varieties and other horticultural plants in vitro, while CY-2 had a higher virulence on several pear varieties including Nanyue, Lvyun, Qiushui and Ningmenghuang. Furthermore, the efficacy of fungicides against these two isolates was evaluated, and carbendazim and flusilazole were found to be the most effective fungicides in inhibiting the growth of these fungal pathogens. Taken together, these findings redefine the N. parvum species and provide potential strategies for the future management of this disease.

Effect of optimized fertilizer on leaf surface and yield of pear trees in repeated cultivation

The results of studies on the effect of optimized fertilization ofpear plantations of the varieties Conferentsia and Osnovianska on morphological changes of the leaf apparatus and the yield of trees grown on dark gray podzolic heavy loamy soil in the Right-Bank Forest-steppe of Ukraine are considered. Under the optimization of mineral nutrition of these pear varieties in the unirrigated plantation, in different age periods of growth and fruiting, a significant increase in the total leaf area, each leafplate and its thickness was observed on the plots of optimized background with the additional introduction of N30 and N30K30. The highest yields of both research pear varieties in the period of fruiting and growth were also provided by additional nitrogen and nitrogen-potassium nutrition with appropriate fertilization on the optimized background. In these cases, there was a significant increase in tree yield compared to the unfertilized, and fertilized with annual application of N90P60K90, where there was a less balanced ratio of N:P:K in plant nutrition, although the total amount of fertilizer was greater. Key words: pear, fertilizer, variety, leaves, harvest, growth periods

Examination of Compatibility of Autochthonous Pear Cultivars from the Region of Northeastern Bosnia with Vegetative Rootstock of the Genus Cydonia sp

Rootstocks of the genus Pyrus are easily adapted to climatic conditions and such trees are more resistant to Erwinia amylovora, but they also have disadvantages because these trees are more lush and difficult to grow in dense composition. The production of pears in a dense composition is a tendency of intensive pear production, and quince rootstocks are used for this purpose, because it is easier to control the height of the stem.
 The increase in the density of the composition in pear orchards is directly related to the use of vegetative rootstocks of less lushness, such as rootstocks of the genus Cydonia sp.The research included five autochthonous pear varieties: Takiša, Jeribasma, Šećerka, Karamut i Huseinbegovača.
 The tests were performed at the location Voćni rasadnik, Špionica, City Srebrenik, Tuzla Canton, Bosnia and Herzegovina, during the vegetation of 2021.
 Morphometric analyzes were performed on a sample of 30 seedlings for each pear variety. Average results are presented using MS Excel software packages.
 Seedlings of grafted varieties on the basis of diameter did not meet the conditions of marketing, while on the basis of vegetative growth, three varieties met the conditions of marketing of planting material. The research was conducted within the project number 02 / 9-712-1-5-4 / 21.
 Grafted autochthonous varieties in the year of grafting showed extremely good adhesion with the vegetative rootstock BA-29, but did not have a good diameter. Due to the possibility of remanence, it is necessary to continue research after planting seedlings in plantations.

Multicriteria Model of Support for the Selection of Pear Varieties in Raising Orchards in the Semberija Region (Bosnia and Herzegovina)

Bosnia and Herzegovina (abbreviated BiH) has great potential for fruit production. BiH has over 1.5 million hectares of agricultural land. In addition, there are excellent climatic conditions for growing fruit. However, although there is a long tradition of fruit production in BiH, this production must be improved. This paper provides guidance on making decisions in fruit growing when there are multiple criteria. All criteria are divided into two groups: economic and technical criteria. The economic criteria are further divided into three subcriteria, namely: marketing costs, orchard construction costs and processing and transport costs. Technical criteria are divided into four subcriteria, namely: fruit, variety resistance, production characteristics and processing and transport. According to these, a multicriteria decision-making model based on linguistic values was created. In order to take advantage of these values, a fuzzy approach was applied. Using this approach, decision-making process is easier because decision making is tailored to human thinking. For the example of raising a new orchard in the area of Semberija, an evaluation of seven different varieties of pears was performed. This problem is solved by applying the method of multicriteria analysis (MCDA). To solve this research problem, the MABAC (Multi-attributive border approximation area comparison) method was used. Using the fuzzy MABAC method, the obtained results show that the Šampionka variety has the best indicators among observed varieties. In addition, the Konferans variety achieved good results, and these two varieties are the first choice for raising a new orchard of pears. The paper validates the results and performs sensitivity analysis. The contribution of this research is to develop a new model of decision making by using a new methodology that facilitates decision making on variety selection. This model and methodology provide a flexible way of making decisions in fruit growing.