Dynamic changes have taken place in the production of sweet cherry (Prunus avium L.) in Poland over the last 20 years. New cultivars with both early- and late-ripening dates have appeared, and modern high-intensity cultivation techniques are being implemented. The main attribute of the fruit, in addition to its unique taste, is its health-promoting properties. In this research, which was conducted at the Warsaw University of Life Sciences in 2021, our main objectives were to evaluate seven selected Czech cherry cultivars (‘Jacinta’; ‘Horka’; ‘Tamara’; ‘Helga’; ‘Fabiola’; ‘Kasandra’; ‘Kordia’) with regard to their dessert quality and contents of biologically active compounds, and to indicate the most valuable cultivar under the conditions of central Poland. The cultivars tested differed in both the fruit quality and health-promoting properties. ‘Jacinta’, ‘Horka’, Tamara’ and ‘Fabiola’ had the largest fruits. The ‘Fabiola’ and ‘Kordia’ fruits had the highest firmness, while the ‘Jacinta’ and ‘Horka’ fruits had the highest soluble solid contents (SSCs) and titratable acidities (TAs). We found the highest SSC-to-TA ratio in the ‘Fabiola’ cultivar. ‘Jacinta’ proved to be the most valuable cultivar in terms of bioactive compounds, and it had the highest antioxidant activity (DPPH). Some of the traits were closely correlated with each other, mainly in relation to the biologically active compounds. Darker fruits contained more bioactive compounds and had a higher antioxidant activity. It was also proved that size of fruits as well as SSC and TA are also correlated with fruit color. Intensively colored fruit are larger and have higher SSC and TA. In sweet cherry fruit, the contents of polyphenols and flavonoids, as well as the high DPPH, are strongly determined by the high content of cyanidin-3-galactoside.

The consumer acceptability of the fruit is very important aspect of distribution. Consumers expect high-quality fruit with high pro-health values. The intention of the research was to assess the quality of hardy kiwi fruit changes during storage in order to provide consumers with high-quality fruit and nutraceutical content. A particular challenge was to assess the storage capacity of the new Polish variety ‘Bingo’^PBR. This is a protected Plant Breeder’s Right (PBR) cultivar in accordance with the Union Internationale pour la Protection des Obtentions Vegetates (UPOV). The storage quality of the fruit of the ‘Bingo’ cultivar was assessed in contrast to the fruit of the ‘Ananasnaya’ cultivar, the basic minikiwi cultivar. The experiment assessed the effect of the fruit ripeness phase during harvest (°Brix −7.7 and 9.0) and the effect of the storage conditions, i.e., normal atmosphere cold store (0.1% CO₂: 21% O₂) versus controlled atmosphere (1.5% CO₂: 1.5% O₂). In the fruit evaluation, the focus was concentrated on changes in the basic color of the peel, firmness, soluble solids content, acidity, as well as the main health-promoting attributes, i.e., antioxidant activity, vitamin C content and total polyphenols. In the experiment, it was found the fruits of ‘Ananasnaya’ variety were almost 40% harder than the fruits of ‘Bingo’^PBR variety. The CA technology (1.5% CO₂: 1.5% O₂) allows for the acceptable firmness of the fruit for up to 56 days of storage. The earlier harvest with an extract content of 7.0–7.5°Brix also promotes higher fruit firmness. Fruits stored in a normal atmosphere cold store ripen faster and are fully ripe after 28 days. ‘Bingo’^PBR variety is characterized by fruits with a higher ascorbic acid content than the fruits of ‘Ananasnaya’ variety. The vitamin C content in fruits increases up to 28 days, regardless of the conditions in which they are stored. The content of polyphenols does not change significantly during storage, which reflects the higher stability of these compounds in fruits.

In order to achieve sustainable food production, non-chemical weed management practices need to be developed for fruit growing. Tailor-made floor management systems enable efficient weed regulation, but they also affect the soil quality in an orchard. In this article, the effects of various floor management systems in a ‘Red Jonaprince’ apple (Malus × domestica Borkh.) orchard on the soil properties and the trees’ nutritional status and initial development during the first two years after the orchard’s establishment were assessed. The experiment was set up in the spring of 2017 in the Experimental Orchard of WULS. ‘Red Jonaprince’ cv. trees grafted on M.9 rootstock were planted with 3.5 × 1 m spacing between them. Different floor management systems were applied to the rows, including the selected organic mulches: Miscanthus × giganteus straw (MG1 and MG2), spent mushroom substrates (SMS1 and SMS2), herbicide strip (HS), clear mechanical soil cultivation (MC), and synthetic black mulch (BC). The organic mulches affected the soil properties significantly. Spent mushroom substrates (SMS1, SMS2) increased the P and K contents in the soil, increased the salinity 10-fold, and retarded the growth in terms of the trunk cross-section area (TCSA) and its increment compared with other systems. Miscanthus × giganteus straw mulch (MG1, MG2) was associated with a more vigorous shoot growth compared with other combinations in the first year of the study as it provided a better tree nitrogen nutritional status. The floor management system affected the generative development of the trees. Mulching with a spent mushroom substrate boosted the flower bud formation intensity, but it did not affect the yielding quantity. Moreover, due to the poor fruit set, the trees mulched with a spent mushroom substrate (SMS2) gave a low initial bearing. High crop loads were noted for the trees treated with black synthetic mulch (BC) and the trees mulched with Miscanthus × giganteus straw (MG1). This was an effect of the tree size rather than the blooming intensity, while there were no differences in the cropping efficiency index (CEI) parameter.

The Saskatoon berry (Amelanchier alnifolia Nutt.) is a prospective and increasingly popular species in Poland. Its main attributes are extremely valuable fruits, rich in anthocyanins with high antioxidant activity, which are very valuable in processing. Studies aimed at comparing the suitability for cultivation under the climatic and soil conditions of east Poland of the three Canadian cultivars of Saskatoon berry (‘Honeywood’, ‘Martin’ and ‘Pembina’), were conducted at the Warsaw University of Life Sciences in 2017–2018. The study evaluated parameters such as yield and fruit quality, as well as the health-promoting value of the fruit. These studies revealed significant differences between the studied cultivars, both in yield and in fruit physicochemical properties, i.e., fruit mass and diameter, firmness, and soluble solids content, as well as in terms of the content of anthocyanins, flavonoids, and polyphenols. These differences were also found between years, which may indicate that the content of the abovementioned compounds is also influenced by annual climatic conditions.

Apples are the most important species in Polish fruit production, and their fresh fruit and processing products occupy a very important place in the European and world food economies. A natural process on the apple market is the replacement of older cultivars with new ones. Consequently, breeding work is being carried out all over the world to obtain new, attractive apple cultivars. In this work, four new apple hybrids obtained in the Department of Pomology and Horticulture Economics at the University of Life Sciences in Warsaw (WULS—SGGW), i.e., two red-skinned hybrids (‘I’P’ and ‘TL’) and two green-skinned hybrids (‘GL’ and ‘LG’), were tested for their main physico-chemical characteristics after harvest and after storage, as well as for their consumer acceptability in a comparison with three popular cultivars in Poland (‘Šampion’, ‘Golden Delicious’, and ‘Ligol’). The hybrids evaluated were differentiated in terms of the tested features. It was found that the fruits of the ‘GL’ hybrid had the highest firmness—both after harvest and post storage; it was also one of the highest-rated overall impressions by consumers among the cultivars tested (only ‘Ligol’ apples had higher scores). The hybrid with low fruit quality and low health-promoting properties at this stage of the study was ‘TL’, whose overall impression was also rated lowest by consumers. The study also showed that the content of bioactive compounds and antioxidant activity of apples can be higher in green-skinned cultivars compared to red-skinned cultivars.

The ultrastructure of stigmatic and stylar secretory tissues was studied in one cultivar of Pyrus communis and six cultivars of Pyrus pyrifolia var. culta (the so-called Nashi pear) using standard light, scanning, and transmission electron microscopy methods. Although both tissues secreted an extracellular fluid necessary for the development of male gametophyte, they differed markedly in the ultrastructure of the extracellular matrix and in the distribution and ultrastructure of organelles. The difference was most evident in regard to the endoplasmic reticulum, which represented the rough, smooth, and vesicular type in stigmatic papillate epidermis and distal stigmatoid tissue cells and occurred mainly as the rough type in form of expanded cisternae filled with fine-fibrillar content in the transmitting tissue of the style.