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Apple scab, caused by Venturia inaequalis, is one of the most damaging pathogens affecting apple species. Cross combinations were made between the Salva cv. (female parent), a valuable local cultivar known for its fruit quality and used as a donor of the Vf resistance gene, and Jonathan (male parent), a variety widely cultivated but susceptible to scab. The Vf gene was first identified in Malus floribunda Clone 821, which was subsequently transferred to commercial varieties through various breeding programs. To confirm the presence of the Vf gene, the progeny from this cross was tested using Marker-Assisted Selection (MAS) with one dominant primer pair (AM19) and two codominant primers (AL07 and VFC) to distinguish between homozygous and heterozygous genotypes. From the crossing, 67 hybrids were obtained, of which 35.8% (24 hybrids) were classified as resistant (heterozygous - Vfvf), while 64.2% (43 hybrids) were classified as susceptible (recessive homozygotes - vfvf). This population of hybrids resistance to Venturia inaequalis represents a good starting point in obtaining cultivars with resistance to scab.

The bacterium Erwinia amylovora is one of the most important pathogens of apples, causing significant damage. During the experimental years, 2021 and 2022, both the temperature and humidity in summer months, were favourable for the occurrence of fire blight in areas with a temperate climate. The absence of major genes for resistance to fire blight makes it difficult to improve apple cultivars in terms of this characteristic. Therefore, studies regarding the behaviour of apple cultivars, in certain environmental conditions, have kept their relevance. The behaviour of the cultivars studied was compared with that of ‘Auriu de Bistrița’, previously known to be susceptible to fire blight. Ten of the twelve cultivars performed well in 2021 and 2022 The results showed that ‘Jonaprim’ was not affected by Erwinia amylovora while other Romanian or foreign cultivars were sporadically affected. ‘Auriu de Bistrița’ presented a higher frequency of specific symptoms, than all the other cultivars.

Erwinia amylovora is the most damaging bacterial disease of quince, causing a lot of damage to this crop. In cases of severe infections, this disease could even cause the death of the tree. The climatic conditions in Bistrita region were favourable for fire blight outbreak in 2022, and gave us the opportunity to study the differences manifested by five quince cultivars ('Aromate', 'Aurii' 'Bereczki', 'Adonia' and 'Cedonia') when naturally infected with Erwinia amylovora Burrill. The second wave of infections, in September, was significantly less damaging than the first one which occurred in June. Overall, after assessing the frequency of the blighted shoots of the mentioned quince cultivars, in June and in September of the year 2022, we concluded that there were significant differences between responses to natural infection Erwinia amylovora of these cultivars. The data showed that the cultivars 'Aromate' and 'Aurii' have a better behaviour than the Hungarian cultivar 'Bereczki', while the Romanian cultivars 'Adonia' and 'Cedonia' appeared to be very susceptible under the climatic conditions of the year 2022 in Bistrita area.

Apple is one of the most consumed fruits in the world and as well one of the most important crops in temperate areas. Apple scab, caused by Venturia inaequalis is damaging diseases that affects apple species and causes up to 70% yield losses depending of cultivar’s resistance. In order to control this disease, costly chemical pesticides are necessary, which increase the pollution of environment by their toxicity. This study is focused on checking the behaviour of certain apple varieties from the pomological collection at UASVM Cluj-Napoca against apple scab infection. Nine apple cultivars ('Fuji Kiku', 'Red Cap', 'Lena', 'Katja', 'Gala Mitchgla', 'Fiesta', 'Yellow', 'Pinova' and 'Reinette du Canada'), were analysed in terms of behaviour to scab attack on leaves and fruits. Visual observations were completed by molecular analyses for the potential presence of the Vf gene in some cases. Combining results from visual observation and molecular assays, the 'Lena' and 'Pinova' cultivars were noted as resistant to scab in our field trial conditions. This indicates a good opportunity to bring them into apple breeding programs for resistance to apple scab.

Black chokeberry (Aronia melanocarpa Michx.) is one of the most cultivated species in recent years, gaining consumer appreciation due to its fruit’s bioactive compounds. This aim of this paper was to study the behavior of two chokeberry cultivars ‘Viking’ and ‘Galicjanka’ under climatic factors in Bistrita area, within an experimental plot established at Fruit Research and Development Station Bistrita. Resistant to low temperatures but sensitive to drought, the two chokeberry cultivars ‘Viking’ and ‘Galicjanka’, have recorded a positive development evolution in pedoclimatic conditions in Bistrita area. For the success of this crop, it is necessary to ensure all the parameters to obtain a high-quality production, so that the deficiencies caused by insufficient water supply can be prevented by implementing technological measures that reduce the negative impact of the ever- changing environment.

To reduce economic losses caused by viruses and phytoplasmas, one of the main preventive measures is to use 'certified' plant material. A nuclear-stock plum collection under insect-proof house is conserved at FRDS Bistrița and consists in twenty-one varieties and one rootstock used for stone fruits propagation. A widening of Romanian plum varieties at Pre-basic category is required to create the opportunity to establish a larger national valuable nuclear-stock collection and to secure the prerequisite for a good transfer of Romanian plum breeding results to the practical application. Plants belonging to other six Romanian plum varieties (Diana, Silvia, Tita, Pescăruș, Gras românesc and Tuleu dulce) were monitored in the field along two consecutive years for potential viral symptoms and tested by serological and molecular tools according EPPO standards. Selected trees of each variety were grafted onto virus-free Saint Julien rootstocks, into insect-proof house, and retested. Three grafted plants from each of the six varieties were chosen to become Candidate Pre-basic material and they were biological indexed onto virus free plants of GF 305. Thus, candidate Pre-basic material, the precursor for Pre-basic category, was established to other six valuable Romanian plum varieties.

Apple scab, caused by Venturia inaequalis is one of the most damaging pathogens that affects apple species. Cross combinations were made between Auriu de Bistrița cv. (female genitor) - a valuable local variety in terms of fruit quality but only tolerant to scab, and Florina cv. (male genitor) used as a donor of Vf resistance gene. It was first detected in Malus floribunda Clone 821, which was later transferred to commercial varieties by different breeding programs. To confirm the presence of Vf gene, progenies resulting from the mentioned combination were tested with MAS (Marker Assited Selection), using two dominant primers pairs (AM19, U1400), and another one codominant (AL07) used to distinguish homozygous and heterozygous genotypes. After the crossing combination, a number of twenty-six hybrids were obtained, of which 50% (13 hybrids) were clasified as resistant (heterozygous), respectively 50% (13 hybrids) as susceptible (recessive homozygotes), so the Mendelian ratio was confirmed.

Ecological farming is increasing worldwide, as more and more consumers prefer chemical-free fruits. As a result, ecological farming is becoming increasingly appealing to European farmers, including those in Romania. However, implementing an effective ecological phytosanitary program remains a challenge for farmers due to limited options and a lack of information about their effectiveness. Romania is a major producer of plums and ranks second in the world after China. Aphids are common pests of plum, and some species are vectors of the damaging Plum pox virus, and therefore require special attention regarding their control. Eight ecological products were tested both in the field and laboratory for a duration of three vegetative periods to determine their efficiency in aphid control. The effects of ecological products were compared with five chemical insecticides known to be effective against aphids. Observations were made 24 and 48 h after spraying. Two of the eight ecological products tested were proven to be efficient in aphid control, Ovipron Top and Prev-Am, with a mortality rate over 90%. The results indicate that these two ecological products are comparable in effectiveness to chemical insecticides and could be suitable candidates for both ecological and conventional treatment programs.

Sixteen plum and eleven sweet cherry newly established commercial orchards in Transylvania, Romania, were the subject of the survey during the vegetative periods of 2020-2021 in order to assess the occurrence of different virus infections. Two blocks of 200 trees from each orchard were monitored by visual observation for virus-like symptoms, especially for Plum pox virus (PPV) in plum orchards. Twenty trees of each plum orchard were then sampled and tested for serological detection of PPV, Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV), Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV) and Myrobalan latent ringspot virus (MLRSV). Similarly, ten trees of each sweet cherry orchard were sampled and tested for the presence of PDV, PNRSV, ApMV, ACLSV, PPV, Arabis mosaic virus (ArMV), Cherry leaf roll virus (CLRV), Raspberry ringspot virus (RpRSV), Strawberry latent ringspot virus (SLRSV) and Tomato black ring virus (TBRV) by serologic assays. Additionally, a few sweet cherry trees suspected to be infected by Little cherry virus-1 (LChV-1) were tested by molecular assay. Unexpectedly, no plum orchards were found to be free of PPV. The average level of PPV infection was 32%. PNRSV occurred in 8.1% and PDV in 1.2% of sampled plum trees. Four out of ten viruses were detected in sweet cherry sampled: PDV (3.6%), ACLSV (0.9%), RpRSV (0.9%) and TBRV (0.9%). No infection with ACLSV, ApMV and MLRSV in plum and PPV, PNRSV, ApMV, ArMV, CLRV, SLRSV and LChV-1 in sweet cherry was detected. Mixed infections occurred at 4.8% in plum, and at 0.9% in sweet cherry trees sampled. The average occurrence of viruses in plum and sweet cherry orchards surveyed in Transylvania was determined at 41.3%, and 6.3% respectively. Overall results revealed a critical situation especially in regards to PPV infections making the success of fruit production in the most surveyed plum orchards quite problematic. Virus infections level in the younger sweet cherry orchards were significantly lower.

The experiment aimed to evaluate some of organic products within a treatment scheme against Eurytoma schreineri Schreiner., on two different plum varieties: Stanley and Reine Claude d’Althan. An experimental scheme of organic treatments by using seven organic products with insecticidal effect was developed and used for evaluation in the field. There were three variants taken into account: organic, conventional and untreated, used as control. Each variant consisted of eight trees belonging to Stanley and Reine Claude d’Althan cvs., four trees for each variety. The frequency occurring of Eurytoma schreineri was evaluated along two consecutive years (2019-2020). Overall results confirmed the sensitivity of Stanley cv. to Eurytoma. schreineri. On the other hand, the results showed that the organic scheme developed was unsatisfactory and there is a risk of considerable losses for farmers who opt for this kind of scheme.

Radon (Rn 222) is a significant contributor to natural radiation exposure in residential environments such as single-family houses and multistory buildings. This study monitored radon activity concentration (RAC) in 455 apartments in 30 multistory buildings in Buzău, Romania. Integrated measurements of the RAC using CR-39 nuclear track detectors were conducted for a period of 3 to 4 months. The results revealed that the RAC varies between buildings, with an annual average between 33 and 77 Bq/m3. This variation may be attributed to poor ventilation and the chimney effect in common ventilation ducts, which may facilitate radon displacement vertically. Also, apartments with low occupancy or inadequate ventilation showed higher radon levels of up to 285 Bq/m3. The study highlights the potential risk of increased radon exposure in energy-efficient buildings due to poor ventilation, emphasizing the need for special attention to radon mitigation measures in building design. The results emphasize that the RAC is influenced by building characteristics, room use, and ventilation, with significant implications for health risks in urban residential environments.

Due to the higher susceptibility of children to ionizing radiation, it is imperative to evaluate the radon activity concentration (RAC) in educational buildings, conduct additional investigations to identify radon entry routes, and implement remedial measures to minimize exposure to this radioactive gas. In Romania, educational buildings are a category of public buildings where it is mandatory to perform RAC measurements. The present study examines data obtained from 41 Romanian educational buildings, where initial and additional radon investigations were performed. The first objective was to identify the factors influencing the variability of the RAC inside the buildings. The second objective was to emphasize the importance of short-term (a few days), continuous measurements in identifying buildings with RAC exceeding the reference level. High RAC values were associated with the classrooms located on the ground floor of the building compared to the administrative ones. The multiple linear regression led to a coefficient of determination of 0.11, the relative humidity and the amount of precipitation being the main variables with a significant impact, kept in the model, the lack of a significant association between the indoor RAC and the radon potential in the soil being obtained. Comparison of the radon long-term integrated measurements with continuous, short-term, led to the suggestion of three different scenarios for the measurement work protocol. By following the suggested modifications, it is possible to accelerate the procedure in situations where the time needed to plan renovations and radon remedial measures is shorter than the time needed to conduct integrated measurements.

Seasonal variations of the radon and radium activity concentrations in karstic water sources originating in karstic formations were investigated as part of a premiere systematic survey conducted in Romania. A database including a total of 228 drinking water samples collected from 30 distinct water sources adjacent to rural communities was compiled. The radon and radium activity concentrations for all seasons, assessed based on solid scintillation, ranged from 2.1 to 19.7 Bq/L and from 0.6 to 3.0 Bq/L, respectively. Overall, the detected radon and radium contents did not exceed the radioprotection standards recommended by national and European legislation. However, in at least one season, the measured values for 31% of the samples exceeded the 11.1 Bq/L maximum contaminant level for radon in drinking water recommended by the Environmental Protection Agency of the United States. The associated radiological risk, reported in terms of annual effective dose, was calculated to be between 9.8 × 10−6 and 6.0 × 10−5 mSv/y for radon and between 5.9 × 10−5 and 2.7 × 10−4 mSv/y for radium, which are considerably below the WHO (World Health Organization) guidelines at a value of 0.1 mSv/y.