Search

Addressing agricultural water scarcity poses a current challenge of growing concern, exacerbated by climate change. This is particularly relevant for stone fruit trees, such as apricot, cultivated in semi-arid zones, where regulated deficit irrigation (RDI) strategies are gaining attention to tackle the challenge. The RDI method involves optimizing various factors based on how the plant responds physiologically to indicators of its water needs. Among these indicators, water potential is considered the most reliable and influential measure. For numerous apricot varieties and diverse geographic locations, research consistently shows that implementing water reduction strategies during non-critical developmental stages of floral bud development or fruit growth does not significantly impact crop yield. However, it does lead to reduced vegetative growth, which could offer additional benefits in crop management. Furthermore, the implementation of RDI strategies leads to advantageous improvements in fruit quality, particularly storage capacity and morphometric and chemical fruit characteristics, such as total soluble solids content. This scoping review study suggests that RDI is a feasible strategy to address water scarcity in apricot cultivation; however, further studies focused on continuous water monitoring alternatives are necessary to optimize RDI techniques. Future research should prioritize optimizing RDI for different growth stages, exploring advanced technologies for precise implementation, and assessing environmental impacts, while addressing research gaps including the influence of climate variability and the interaction with other agronomic practices, to refine RDI strategies and enhance apricot orchard sustainability and productivity. [ABSTRACT FROM AUTHOR]

Orchard thinning can avoid biennial bearing and improve fruit quality, which is a necessary agronomic section in orchard management. The existing methods of artificial fruit thinning and chemical spraying are no longer suitable for the development of modern agriculture. With the continuous acceleration of the construction process of modern orchards, blossom thinning mechanization has become an inevitable trend in the development of the orchard flower and fruit management. Based on relevant reports in the past 20 years, the paper discusses the current level of development of mechanized blossom thinning technologies and equipment in orchards from three aspects: mechanism research, machine development, and intelligent upgrading. Firstly, for thinning mechanism research, three directions were investigated: the rope flexible hitting force, thinning agronomic requirements, and the fruit tree growth model between thinning and fruit yields. Secondly, for marketable machine developments, two types of machines were investigated: the hand-held thinner and tractor-mounted thinner. The hand-held thinner is mainly suitable for traditional old orchards with a messy canopy structure, especially in the interior and top of the canopy. The tractor-mounted thinner is mainly suitable for orchards with the same crown structure, such as the hedge type, trunk type, and V-type. Thirdly, for equipment intelligent upgrading, the research of the intelligent detection algorithm for inflorescence on the fruit tree was investigated, for species including the apple, pear, citrus, grape, litchi, mango, and apricot. Finally, combining the advantages and disadvantages of the research, the authors propose thoughts and prospects, which can provide a reference for the design and applications of orchard mechanized blossom thinning. [ABSTRACT FROM AUTHOR]

Irrigated agriculture is facing a serious problem of water scarcity, which could be mitigated by optimizing the application of regulated deficit irrigation (RDI) strategies. For this reason, the aim of our study was to determine irrigation thresholds based on direct water status indicators of apricot trees under RDI to maximize water productivity. Three treatments were tested: (i) Control (CTL), irrigated at 100% of the crop evapotranspiration (ETc) during the entire crop cycle; (ii) RDI1, irrigated as CTL, except during fruit growth stages I–II when irrigation was reduced by 20% of CTL, and during late post-harvest, with an irrigation threshold of a moderate water stress of −1.5 MPa of stem water potential (Ψs); and (iii) RDI2, irrigated as RDI1, but during late post-harvest using a severe water stress threshold of −2.0 MPa of Ψs. As the irrigation scheduling of RDI1 and RDI2 did not affect yield and fruit quality, the crop water productivity was increased by 13.2 and 25.6%, respectively. This corresponded to 1124 and 2133 m3 ha−1 of water saved for RDI1 and RDI2. A water stress integral of 30.2 MPa day during post-harvest could be considered optimal since when 41 MPa day was accumulated, vegetative growth was reduced by 35%. The non-sensitive periods to water deficit were delimited by the accumulation of growing degree days (GDD) from full bloom, the end of fruit growth stages I–II corresponded to an accumulation of 640 °C GDD, and the beginning of the late post-harvest to an accumulation of 1840 °C GDD. [ABSTRACT FROM AUTHOR]

MADS-box is an important transcriptional regulatory element in plant growth. The MIKC-type MADS-box genes play important roles. However, the identification and evolutionary investigation of MIKC-type MADS-box family members in Rosaceae have been inadequate. Therefore, based on whole-genome data from Prunus dulcis, Prunus salicina, Prunus armeniaca, Prunus persica, Prunus mira, and Amygdalus nana, we depicted the evolution and divergence patterns of MIKC-type MADS-box family genes. In this study, we found 222 MIKC-type MADS-box genes from six Rosaceae species. These genes were classified into five clades, and only motif 1 was identified across all MIKC-type MADS-box proteins, except PdMADS42 and PmiMADS16. The structural properties of these genes significantly varied in sequence lengths between species, despite the high levels of similarity in exon lengths and numbers. MIKC-type MADS-box genes were found to have mostly been limited through purifying selection processes. Remarkably divergent regions were found inside the MIKC-type MADS-box genes' domains, where clade III displayed more conserved activities and may have retained more original functions over the evolutionary process; clade I, on the other hand, may have undergone substantial functional limitations in a specific functional role. These findings provide the groundwork for future research into the molecular evolutionary processes of the plant MIKC-type MADS-box gene family. [ABSTRACT FROM AUTHOR]

Blossom and twig blight, caused by Monilinia spp., is the main disease in apricot trees. In this study, we installed transparent rain shelters in apricot orchards to study their influence on the modification of the microclimate at the level of the tree canopy and on the reduction in moniliosis damage in twigs. Rain shelters significantly reduced the leaf wetness time measured within the foliage compared to the unsheltered trees (a reduction of between 43% and 67%). However, very few differences were observed in the daily averaged air temperature (up to 6%) and daily averaged air relative humidity (up to 1%). In the first experiment, on the apricot variety Bergarouge® (CEP Innovation, Lyon, France), moniliosis damage on twigs in the absence of phytosanitary protection was reduced by up to 62% for the trees provided with rain protection compared to the trees that did not receive rain shelters. A second experiment, involving five apricot tree varieties, made it possible to verify that fungicide protection could be reduced for the trees protected by rain covers, reducing moniliosis damage on twigs compared to full fungicide protection combined without rain protection. Finally, a third experiment comprising two apricot tree varieties has shown that in organic orchards, rain protection provides protection against moniliosis (twig blight) that is equivalent to an organic farming fungicide protection programme based on the use of copper sulphate and calcium polysulphide. [ABSTRACT FROM AUTHOR]

The Prunus genus contains many of the most economically significant arboreal crops, cultivated globally, today. Despite the economic significance of these domesticated species, the pre-cultivation ranges, processes of domestication, and routes of prehistoric dispersal for all of the economically significant species remain unresolved. Among the European plums, even the taxonomic classification has been heavily debated over the past several decades. In this manuscript, we compile archaeobotanical evidence for the most prominent large-fruiting members of Prunus, including peach, apricot, almonds, sloes, and the main plum types. By mapping out the chronology and geographic distributions of these species, we are able to discuss aspects of their domestication and dispersal more clearly, as well as identify gaps in the data and unanswered questions. We suggest that a clearer understanding of these processes will say a lot about ancient peoples, as the cultivation of delayed return crops is an indicator of a strong concept of land tenure and the specialization of these cultivation strategies seems to be tied to urbanism and reliable markets. Likewise, the evolution of domestication traits in long-generation perennials, especially within Rosaceae, represents awareness of grafting and cloning practices. [ABSTRACT FROM AUTHOR]

'Candidatus Phytoplasma prunorum' is causing ever increasing economic losses through the decline of apricot trees in European countries, e.g., Hungary. In this study, the pathogen was identified from plant tissues and insects by nested-PCR. The insect species were identified via morphology and molecular methods. The incidence of the pathogen was 29.6% in randomly selected apricot trees. Most of the infected trees with symptoms died within a year. These results show that phytoplasma is significantly present and causes damage in the investigated plantations. The only known insect vector of this phytoplasma is the plum psyllid, Cacopsylla pruni, which was regularly encountered in the sampled apricot orchards and in their surroundings. In a two-year study, several adults among the sampled specimens were observed to be infected by the pathogen. This observation further confirms the role of the plum psyllid in vectoring the phytoplasma. All the sampled plum psyllid adults belonged to the 'B' biotype. Besides C. pruni, Cacopsylla crataegi was abundant in the samples. Several adults of the latter species were also infected by the pathogen 'Ca. Phytoplasma prunorum'. The rates of occurrence of this phytoplasma in male and female adults of the two psyllid species appeared to be similar. The examined C. crataegi individuals showed genetic differences from each other and from specimens included in a previous investigation. [ABSTRACT FROM AUTHOR]

Soil sickness syndrome in Japanese pear (Pyrus pyrifolia (Burm.f.) Nakai) affects the growth of the tree and decreases fruit yield. This study investigated the growth-inhibitory activity in Japanese pear (Pyrus pyrifolia (Burm.f.) Nakai) using the rhizosphere soil assay method to elucidate the characteristics of growth-inhibitory substances in Japanese pears. As a result, the root bark had the highest growth inhibitory activity during the growing season of the Japanese pear. For comparative analysis, the growth-inhibitory activities of Japanese apricots (Prunus mume Sieb. Et Zucc.) and figs (Ficus carica L.) were also investigated. Similar to the Japanese pear, the root bark of Japanese apricots and figs had a higher inhibition rate than the root pith. Like Japanese apricots and figs, it was inferred that the growth inhibitory substances accumulate in the bark of the Japanese pear. Furthermore, soil sickness syndrome in Japanese pear saplings did not occur when a fragment of Japanese pear shoots or thick roots was mixed with non-pear soil (soil with no history of Japanese pear cultivation). Based on these findings, it is considered that the condition of soil sickness in Japanese pear is caused by the accumulation of phenolic compounds such as arbutin, which is accumulated in the bark of the tree, secreted from the roots, and subsequently builds up in the soil. Additionally, the degree of occurrence of soil sickness syndrome depending on the rootstock was clarified. It was observed that the rate of growth inhibition was significantly higher in Pyrus betulifolia (Birchleaf pear) than in Pyrus pyrifolia (Japanese pear). Even when Japanese pear trees were planted in soils with no history of Japanese pear cultivation, the initial growth of P. betulifolia was 1.4 times that of P. pyrifolia. It is suggested that P. betulifolia is weak against soil sickness, but is excellent at initial growth itself. Our findings are important because P. pyrifolia is used for cultivation, in combination with other mitigation measures, such as soil dressing in replanted fields. [ABSTRACT FROM AUTHOR]

Blossom and twig blight, caused by Monilinia spp., is the main disease in apricot trees. In this study, we installed transparent rain shelters in apricot orchards to study their influence on the modification of the microclimate at the level of the tree canopy and on the reduction in moniliosis damage in twigs. Rain shelters significantly reduced the leaf wetness time measured within the foliage compared to the unsheltered trees (a reduction of between 43% and 67%). However, very few differences were observed in the daily averaged air temperature (up to 6%) and daily averaged air relative humidity (up to 1%). In the first experiment, on the apricot variety Bergarouge® (CEP Innovation, Lyon, France), moniliosis damage on twigs in the absence of phytosanitary protection was reduced by up to 62% for the trees provided with rain protection compared to the trees that did not receive rain shelters. A second experiment, involving five apricot tree varieties, made it possible to verify that fungicide protection could be reduced for the trees protected by rain covers, reducing moniliosis damage on twigs compared to full fungicide protection combined without rain protection. Finally, a third experiment comprising two apricot tree varieties has shown that in organic orchards, rain protection provides protection against moniliosis (twig blight) that is equivalent to an organic farming fungicide protection programme based on the use of copper sulphate and calcium polysulphide.

The Prunus genus contains many of the most economically significant arboreal crops, cultivated globally, today. Despite the economic significance of these domesticated species, the pre-cultivation ranges, processes of domestication, and routes of prehistoric dispersal for all of the economically significant species remain unresolved. Among the European plums, even the taxonomic classification has been heavily debated over the past several decades. In this manuscript, we compile archaeobotanical evidence for the most prominent large-fruiting members of Prunus, including peach, apricot, almonds, sloes, and the main plum types. By mapping out the chronology and geographic distributions of these species, we are able to discuss aspects of their domestication and dispersal more clearly, as well as identify gaps in the data and unanswered questions. We suggest that a clearer understanding of these processes will say a lot about ancient peoples, as the cultivation of delayed return crops is an indicator of a strong concept of land tenure and the specialization of these cultivation strategies seems to be tied to urbanism and reliable markets. Likewise, the evolution of domestication traits in long-generation perennials, especially within Rosaceae, represents awareness of grafting and cloning practices.

Fruit growth is a biophysical process that depends mainly on the daily balance between vascular (xylem and phloem) and transpiration flows. This work examines the seasonal and daily behaviour of apricot fruit growth as well as their vascular and transpiration flows. Seasonal patterns of the shoot and fruit growth, as well as fruit surface conductance and dry matter accumulation, were monitored at regular times intervals during the season on "Farbela" and "Ladycot" cultivars. In addition, the daily courses of leaf and stem water potentials and leaf gas exchanges were monitored at 66 and 109 DAFB. On the cultivar "Farbela", the daily patterns of phloem, xylem, and transpiration flow to and from the fruit were determined through precise and continuous monitoring of fruit diameter variations. Branch sap flow was also determined through the thermal balance method. Apricot fruit growth showed a double sigmoid pattern, typical of other drupaceous species. Stem and leaf water potential maintained values above the stress threshold, and in the last part of the season, the leaf photosynthetic rate increased. Leaves received higher sap flow in the morning and at midday, while a higher amount of xylem water was moved to the fruit in the late afternoon. Fruit showed high transpiration rates, which led to fruit shrinkage during the warmest hours of the day. High xylem inflows balanced the transpiratory losses, while phloem import was lower and occurred mainly during the mid-day hours. As a result, the fruit grew mostly in the late afternoon and night, and its growth was sustained mainly by xylem fluxes, which represented over 90% of the fruit's total inflows. Later in the season, fruit transpiration and xylem flow decreased but did not stop even at harvest. Phloem import increased its importance throughout the season and, in the final stages, accounted for 36% and then 66% of the daily relative contribution to fruit growth. This knowledge represents a starting point to improving apricot orchard management in terms of irrigation and fertilisation. [ABSTRACT FROM AUTHOR]

Fruit growth is a biophysical process that depends mainly on the daily balance between vascular (xylem and phloem) and transpiration flows. This work examines the seasonal and daily behaviour of apricot fruit growth as well as their vascular and transpiration flows. Seasonal patterns of the shoot and fruit growth, as well as fruit surface conductance and dry matter accumulation, were monitored at regular times intervals during the season on “Farbela” and “Ladycot” cultivars. In addition, the daily courses of leaf and stem water potentials and leaf gas exchanges were monitored at 66 and 109 DAFB. On the cultivar “Farbela”, the daily patterns of phloem, xylem, and transpiration flow to and from the fruit were determined through precise and continuous monitoring of fruit diameter variations. Branch sap flow was also determined through the thermal balance method. Apricot fruit growth showed a double sigmoid pattern, typical of other drupaceous species. Stem and leaf water potential maintained values above the stress threshold, and in the last part of the season, the leaf photosynthetic rate increased. Leaves received higher sap flow in the morning and at midday, while a higher amount of xylem water was moved to the fruit in the late afternoon. Fruit showed high transpiration rates, which led to fruit shrinkage during the warmest hours of the day. High xylem inflows balanced the transpiratory losses, while phloem import was lower and occurred mainly during the mid-day hours. As a result, the fruit grew mostly in the late afternoon and night, and its growth was sustained mainly by xylem fluxes, which represented over 90% of the fruit’s total inflows. Later in the season, fruit transpiration and xylem flow decreased but did not stop even at harvest. Phloem import increased its importance throughout the season and, in the final stages, accounted for 36% and then 66% of the daily relative contribution to fruit growth. This knowledge represents a starting point to improving apricot orchard management in terms of irrigation and fertilisation.

In the recent years, an important renewal of apricot cultivars is taking place worldwide with the introduction of a large number of new releases, which are replacing traditional and local cultivars in many situations. To study the current genetic diversity, a group of 202 apricot accessions, including landraces and releases from breeding programs in several countries, has been characterized using 13 microsatellite markers. The diversity parameters showed higher diversity in modern releases than in landraces, but also suggested a loss of diversity associated with recent breeding. Two main clusters according to the pedigree origin of the accessions were clearly differentiated in the phylogenetic analysis based on Nei’s genetic distance. The first group comprised mostly European and North American traditional cultivars, and the second group included the majority of recent and commercial releases from breeding programs. Further population analyses showed the same clustering trend on the distribution of individuals and clusters, confirming the results obtained in the molecular phylogenetic analysis. These results provide a sight of the erosion and the decrease of the genetic diversity in the currently grown apricot and highlight the importance of preserve traditional cultivars and local germplasm to assure genetic resources for further breeding.

Plum pox virus (PPV) is the most important limiting factor for apricot (Prunus armeniaca L.) production worldwide, and development of resistant cultivars has been proven to be the best solution in the long-term. However, just like in other woody species, apricot breeding is highly time and space demanding, and this is particularly true for PPV resistance phenotyping. Therefore, marker-assisted selection (MAS) may be very helpful to speed up breeding programs. Tightly linked ParPMC1 and ParPMC2, meprin and TRAF-C homology (MATH)-domain-containing genes have been proposed as host susceptibility genes required for PPV infection. Contribution of additional genes to PPV resistance cannot be discarded, but all available studies undoubtedly show a strong correlation between ParPMC2-resistant alleles (ParPMC2res) and PPV resistance. The ParPMC2res allele was shown to carry a 5-bp deletion (ParPMC2-del) within the second exon that has been characterized as a molecular marker suitable for MAS (PMC2). Based on this finding, we propose here a method for PPV resistance selection in apricot by combining high-throughput DNA extraction of 384 samples in 2 working days and the allele-specific genotyping of PMC2 on agarose gel. Moreover, the PMC2 genotype has been determined by PCR or by using whole-genome sequences (WGS) in 175 apricot accessions. These results were complemented with phenotypic and/or genotypic data available in the literature to reach a total of 325 apricot accessions. As a whole, we conclude that this is a time-efficient, cost-effective and straightforward method for PPV resistance screening that can be highly useful for apricot breeding programs.

Stone fruit trees of genus Prunus, like other temperate woody species, need to accumulate a cultivar-specific amount of chilling during endodormancy, and of heat during ecodormancy to flower properly in spring. Knowing the requirements of a cultivar can be critical in determining if it can be adapted to a particular area. Growers can use this information to anticipate the future performance of their orchards and the adaptation of new cultivars to their region. In this work, the available information on chilling- and heat-requirements of almond, apricot, plum, peach, and sweet cherry cultivars is reviewed. We pay special attention to the method used for the determination of breaking dormancy, the method used to quantify chilling and heat temperatures, and the place where experiments were conducted. The results reveal different gaps in the information available, both in the lack of information of cultivars with unknown requirements and in the methodologies used. The main emerging challenges are the standardization of the conditions of each methodology and the search for biological markers for dormancy. These will help to deal with the growing number of new cultivars and the reduction of winter cold in many areas due to global warming.

Apricot fruits provide important health, economic, and nutritional benefits. Weeds damage apricot production directly and host the pests that cause damages to apricot trees. However, very few studies are available on weed control in apricot orchards. This research work was aimed at evaluating five cover crops for weed suppression in apricot orchard. The effect of living, mowed, and soil-incorporated cover corps on weeds was recorded and compared with glyphosate application and mechanical weed control. The cover crops were Vicia villosa Roth., Vicia pannonica Crantz, Triticale + V. pannonica, Phacelia tanacetifolia Benth., and Fagopyrum esculentum Moench. Five major weed species in the experimental area were Amaranthus retroflexus L., Convolvulus arvensis L., Tribulus terrestris L., Sisymbrium officinale (L.) Scop., and Sorghum halepense (L.) Per. The highest biomass production was noted for Triticale + V. pannonica in 2015 and for P. tanacetifolia in 2016. Living cover crops were effective in decreasing the weed biomass compared with the control. Both mowing and soil incorporation of cover crops were effective in decreasing weed richness and density over control. Mowed or soil-incorporated cover crops were more effective than herbicide or mechanical weed control, while F. esculentum was the least effective cover crop for suppressing weeds in apricot orchard. The results of our studies implied that cover crops could be used for weed control in apricot, and their mowing or soil incorporation could enhance their efficacy. [ABSTRACT FROM AUTHOR]

Apricot fruits provide important health, economic, and nutritional benefits. Weeds damage apricot production directly and host the pests that cause damages to apricot trees. However, very few studies are available on weed control in apricot orchards. This research work was aimed at evaluating five cover crops for weed suppression in apricot orchard. The effect of living, mowed, and soil-incorporated cover corps on weeds was recorded and compared with glyphosate application and mechanical weed control. The cover crops were Vicia villosa Roth., Vicia pannonica Crantz, Triticale + V. pannonica, Phacelia tanacetifolia Benth., and Fagopyrum esculentum Moench. Five major weed species in the experimental area were Amaranthus retroflexus L., Convolvulus arvensis L., Tribulus terrestris L., Sisymbrium officinale (L.) Scop., and Sorghum halepense (L.) Per. The highest biomass production was noted for Triticale + V. pannonica in 2015 and for P. tanacetifolia in 2016. Living cover crops were effective in decreasing the weed biomass compared with the control. Both mowing and soil incorporation of cover crops were effective in decreasing weed richness and density over control. Mowed or soil-incorporated cover crops were more effective than herbicide or mechanical weed control, while F. esculentum was the least effective cover crop for suppressing weeds in apricot orchard. The results of our studies implied that cover crops could be used for weed control in apricot, and their mowing or soil incorporation could enhance their efficacy.

The aim of the apricot-breeding program in the Horticultural Faculty in Lednice, that has been developed since 1981, is to obtain new adaptable cultivars, which combine most of the valuable biological traits. Standard breeding techniques, such as crossing by emasculation and hand pollination, self-pollination and open pollination, were employed. A total of 1.154 crossings were produced from more than 110 different parents. So far more than 20,000 seedlings have been obtained, of which about 13,000 have already been evaluated. The most interesting selections were grafted and planted in trial orchards (we now have more than 650 elite genotypes). Ten of these have already been registered, and further promising new hybrids have been submitted for registration and law right protection (Betinka, Candela, Sophia and Adriana). The basic prerequisite for the initiation of the breeding program was a large collection of genetic resources, established and gradually supplemented since the 1970s. At the present time, we preserve and manage more than 300 accessions of apricot trees. In the frame of the descriptive work of the genetic resources and in order to use in breeding, a collection of apricots has been evaluated. We selected the genotypes and characters relating to an increased level of adaptation to the environment.

Cost-Effective and Time-Efficient Molecular Assisted Selection for PPV Resistance in Apricot Based on ParPMC2 Allele-Specific PCR. Reference 1 Polo-Oltra Á., Romero C., López I., Badenes M.L., Zuriaga E. Cost-Effective and Time-Efficient Molecular Assisted Selection for PPV Resistance in Apricot Based on ParPMC2 Allele-Specific PCR. The authors would like to make the following correction to the published paper [[1]]: Revise the sequence of the 3 primers in Section 2.2 PMC2 Genotype by Allele-Specific PCR Assay from "PMC2 marker genotyping was performed using the allele-specific for-ward primer (PMC2-F-alleleR: 5'-GTCATTTTCATTGATGTCATTCA-3' or PMC2-F-alleleS: 5'-GTCATTTTCATTGATGTCATTCA-3') and one common reverse primer (PMC2-R: 5'-GTCATTTTCATTGATGTCATTCA-3'), as described by Zuriaga et al." to "PMC2 marker genotyping was performed using the allele-specific forward primer (PMC2-F-alleleR: 5'-GTCATTTTCATTGATGTCATTCA-3', or PMC2-F-alleleS: 5'-GTCGTTTTCATTGATGTCCAAAC-3', respectively) and one common reverse primer (PMC2-R: 5'-GTGCTCTTTCACATTCTTGCTC-3'), as described by Zuriaga et al.". [Extracted from the article]

Defoliation (DF) on peach (Prunus persica L.) and Japanese apricot (Prunus mume Sieb. et Zucc.) trees caused by a hailstorm in 2017, year 1, was investigated for its effects on growth and fruit yield in South Korea over four years, comparing with recovery effects of the DF trees treated with repeated immediate pruning (IP) right after the storm. Treatments included 0–10, 10–40, 40–70, and 70–100% of DF trees, with 0–10, 10–40, 40–70, and 70–100% of DF + IP trees. The hailstorms increased the damages to shoots for peaches and to shoots and scaffold for Japanese apricot trees in year 1, with fruit yield reduced more than 80% observed on 10–100 DF of both fruit species. The IP treatment increased the number of new shoots in years 2–4 but reduced shoot length and diameter of peach and Japanese apricot trees. Tree canopy in years 2–4 was reduced on 40–100 DF of peach trees and on 70–100 of DF and DF + IP of Japanese apricot trees. The 40–100 DF Japanese apricot trees resulted in a fruit yield index of less than 90% for years 2–4, which was observed on 40–100 DF+IP trees only in year 2 due to balanced tree vegetative and reproductive growth. [ABSTRACT FROM AUTHOR]

Fruit-wheat intercropping is an important way to resolve the land competition between fruit and grain and ensure food security. However, there is little research on the mechanism of wheat yield formation and its response to nitrogen fertilizer under long-term shading. From 2016 to 2017, wheat variety "Xindong 20" was selected, and four shading treatments were set: shading at jointing stage 10%-shading at heading stage 25% (S1), 20%–50% (S2), 30%–75% (S3), normal light (S0) and four nitrogen fertilizer (N0: 0 kg ha−1, N1: 103.5 kg ha−1, N2: 138 kg ha−1, N3: 172.5 kg ha−1). The results show that compared with S0, wheat leaf area index (LAI), chlorophyll a, b and a + b content under S1 increase by 14.9–57.4%, 2.9–24.5%, 16.5–28.9%, 7.8–25.5%, respectively, and they decrease significantly under S2 and S3. With the increase in the shading range, the net photosynthesis rate (Pn), transpiration rate (Tr), stomatal conductance (gs), and non-photochemical quentum coefficient (NPQ) decrease significantly, while the actual photochemical efficiency (ΦPSII) and the photochemical quenching coefficient (qP) increase significantly. Under S1, S2, and S3, the total dry matter accumulation (TDA), the dry matter accumulation of reproductive organs (DAR), and the yield decrease with the increase in shading range. Under the S0 and S1 conditions, compared with other nitrogen treatments, LAI, chlorophyll content, Pn, ΦPSII, qP, TDA, DAR, and yield of wheat under N2 treatment increase by 4.1–366.9%, 5.7–56.3%, 3.0–131.7%, 6.7–87.5%, 3.7–96.9%, 7.1–340.8%, 0.3–323.0%, 1.5–231.2%. Therefore, under jujube-wheat intercropping, and apricot-wheat and walnut-wheat with light shade in the early stage, photosynthetic capacity of wheat leaves and dry matter accumulation and transfer to grains can be regulated by proper nitrogen application, which is beneficial to compensate for the negative effects of insufficient light on wheat yield; under moderate or excessive shading conditions (apricot-wheat and walnut-wheat in full fruit period), the regulating effect of nitrogen application on wheat is reduced, and the nitrogen application should be moderately reduced. [ABSTRACT FROM AUTHOR]

Nutritional and commercial value of the apricot fruits depends on the interaction among several factors, including the management strategies, the environmental conditions, and the genotype. This study aimed to evaluate the effect of orchard management and pedoclimatic conditions on apricot fruit quality traits (soluble solids, titratable acidity, dry matter and soluble solids and titratable acidity ratio) and phytochemical content (total phenolic content and antioxidant activity). Two apricot cultivars (Kioto* and Pieve*) were subjected to three different organic systems: (i) a standard management (BAU), (ii) an innovative diversified system with reduced tillage based on the natural cover conservation (INC) and (iii) an innovative diversified system with introduction of different cover crops (ICC), for two consecutive years (2019–2020). Overall, besides the effect of the climatic conditions, the multivariate analysis revealed the role of management systems, rather than genotype, on the quality of apricot fruits. In particular, INC soil management positively affected soluble solids, titratable acidity and dry matter parameters, especially in environments with low precipitation and high solar radiation (20.7 ± 1.7 g 100 g−1 FW, 19.9 ± 2.5 g MA 100 g−1 FW and 0.23 ± 0.2 g 100 g−1 FW respectively). In addition, the results indicate that ICC management showed the highest antioxidant values (1.45 ± 0.19 μg of Trolox equivalent (TE) 100 mg−1 FW), especially in the environment with high precipitation. This study was a useful tool for farmer to choose an effective organic system management in order to obtain fruits with high quality parameters. [ABSTRACT FROM AUTHOR]

In the recent years, an important renewal of apricot cultivars is taking place worldwide with the introduction of a large number of new releases, which are replacing traditional and local cultivars in many situations. To study the current genetic diversity, a group of 202 apricot accessions, including landraces and releases from breeding programs in several countries, has been characterized using 13 microsatellite markers. The diversity parameters showed higher diversity in modern releases than in landraces, but also suggested a loss of diversity associated with recent breeding. Two main clusters according to the pedigree origin of the accessions were clearly differentiated in the phylogenetic analysis based on Nei's genetic distance. The first group comprised mostly European and North American traditional cultivars, and the second group included the majority of recent and commercial releases from breeding programs. Further population analyses showed the same clustering trend on the distribution of individuals and clusters, confirming the results obtained in the molecular phylogenetic analysis. These results provide a sight of the erosion and the decrease of the genetic diversity in the currently grown apricot and highlight the importance of preserve traditional cultivars and local germplasm to assure genetic resources for further breeding. [ABSTRACT FROM AUTHOR]

In the last years, an important renewal of plant material from different breeding programs is taking place in apricot in order to improve resistance to biotic stresses, extension of the harvest season, fruit quality, and productivity. However, the graft compatibility of many of these cultivars with most popular Prunus rootstocks is unknown, and this is an essential agronomical trait for their better performance and longevity. Hence, the introduction of new cultivars requires knowledge of the extent and nature of incompatibility reactions before releasing these cultivars on the market. In this study, the determination of graft compatibility was carried out in 13 new apricot cultivars grafted on four Prunus rootstocks: 'Marianna2624' (P. cerasifera × P. musoniana), 'Miragreen' (P. cerasifera × P. davidiana), 'Mirared' (P. cerasifera × Nemared), and 'Montclar' (P. persica L. seedlings) at early stages of development. By combining cytomorphological, anatomical, and phenylalanine ammonia-lyase (PAL) gene expression analysis at the graft interface, as well as different vegetative parameters, the results highlighted 'Miragreen' and 'Mirared' as promising rootstocks for apricot, showing the highest degree of compatibility with more than 90% of the apricot cultivars. These results provide useful information for breeders and growers by selecting the most suitable scion-rootstock for efficient orchard design by planting compatible graft combinations. [ABSTRACT FROM AUTHOR]

Irrigation is a key factor for different physiological aspects of fruit trees. Therefore, such irrigation protocols that can save water consumption during irrigation and maintain fruit trees productivity are an essential goal especially under semiarid climate conditions. The aim of this 3-year apricot study was to investigate the effect of four deficit irrigation (DI) treatments (control, moderate regulated deficit irrigation: RDIm, severe RDI: RDIs and continuous DI: CDI) on 15 tree physiological properties (chilling requirement—CR, heat requirement—HR, days from end—dormancy until fruit harvest—DEDFH, sum of growing degree days—sGDD, total number of buds—TNB, number of flower buds—NFB, number of vegetative buds—NVB, starting date of flowering—SDF, number of opened flower buds—NOFB, flower bud abscission—FBA, fruit set—FS, seasonal vegetative growth—SVG, fruit number per tree—FNT, fruit weight—FW, fruit yield—FY), and on two tree chemical properties (total soluble carbohydrates—TSC and total proline content—TPC) on apricot cultivars 'Ninfa' and 'Canino' in Egypt. Results showed that both DI treatments and cultivars significantly influenced the values of CR, HR, TNB, SDF, NOFB, FS, SVG, FNT, FY, TSC, and TPC. Values of FBA were significantly affected by years and DI treatments, while sGDD by years and cultivars. Values of DEDFH, NFB, and FW were significantly influenced only by cultivars, while NVB only by DI treatments. The RDIm treatment gave the most acceptable values for most measured properties compared to the fully irrigated control treatment. Prediction based model analysis demonstrated that generalized linear models (GLMs) can be predictors for the measured tree properties in the DI treatments. The best goodness-of-fit of the predicted GLMs was reached for HR, NOFB, FS, SVG, FNT, TSC, and TPC. In all the four DI treatments, 22 pair-variables (TNB versus (vs.) NFB, TNB vs. NOFB, TNB vs. NOFB, NFB vs. NOFB, NFB vs. FNT, NFB vs. FY, NFB vs. FW, NOFB vs. SVG, NOFB vs. FNT, NOFB vs. FY, FS vs. FNT, FS vs. FY, SVG vs. FNT, SVG vs. FY, SVG vs. TSC, FNT vs. FY, FY vs. FW, CR vs. TSC, HR vs. TNB, HR vs. NFB, HR vs. FNT, HR vs. FY, and NOFB vs. FBA) correlated significantly in Pearson correlation and regression analyses. Principal component analyses explained 82% of the total variance and PC1, PC2, and PC3 explained 23, 21, and 15% of the total variance and correlated with the HR, TNB, FS, FNT and FY; FBA, SVG, TSC, and TPC; and NFB, NVB and NOFB, respectively, indicating strong connections among tree physiological and chemical properties. In conclusion, DI techniques using moderate water deficits can be managed successfully in apricot production under semiarid Mediterranean climate conditions such as the one in Egypt. [ABSTRACT FROM AUTHOR]

The improvement of previously described protocols for the regeneration of shoots from 'Canino' mature seed hypocotyl slices has been accomplished. The effects of different factors such as the part of the hypocotyl used, vacuum-infiltration, 2,4-Dichlorophenoxyacetic acid pulse, vacuum-infiltration and sonication on regeneration and transient transformation were analyzed. When the three slices obtained from the hypocotyls were evaluated separately on regeneration medium, the highest percentages of regenerating explants were achieved in the part close to the epicotyl and in the central part. On the other hand, sonication of the explants for 30 s followed by vacuum-infiltration during Agrobacterium infection for 20 min allowed for an increase in the transformation events. The application of these modifications to the procedure increased the regeneration efficiencies, and transient transformation events and may reduce the frequency of failed experiments. An efficient regeneration/transformation protocol could facilitate its use as a biotechnological technique for apricot breeding. [ABSTRACT FROM AUTHOR]

The aim of the present experiment was to determine if the supply of biofertilizers could differently stimulate the native microbiota, thus determining different patterns of organic material decomposition processes. The microbial composition of soil and litter was investigated by next generation sequencing using a metabarcoding approach. The chemical structure of the decomposing litterbags was investigated through the TG-DTA analysis and NIR spectroscopy. The study was conducted in an apricot orchard in Italy, and two different type of biofertilizers (AMF and Trichoderma spp.) were compared to unfertilized control over one year. Bacteria and fungi in soil, 162 days from litter deposition, evidenced differentiated clusters for control and both biofertilizers; on the other hand, only fungal composition of litterbags was modified as a consequence of Trichoderma spp. supply; no effect was observed in the bacterial community of litterbags. NIR and TG-DTA analysis evidenced a significant change over time of the chemical composition of litterbags with a faster degradation as a consequence of Trichoderma spp. supply testified by a higher degradation coefficient (1.9) than control (1.6) and AMF (1.7). The supply of biofertilizers partially modified the bacteria community of soil, while Trichoderma spp. Influenced the fungal community of the litter. Moreover, Trichoderma spp. Evidenced a faster and higher degradation of litter than AMF-biofertilizers, laying the foundation for an efficient use in orchard. [ABSTRACT FROM AUTHOR]

The effects of preharvest melatonin treatment on apricot crop yield and fruit quality properties at harvest and during storage have not yet been investigated. Apricot trees, of the 'Colorado' and 'Mikado' cultivars, were sprayed with 0.1 mM melatonin at three key points of fruit development. Fruit were harvested at commercial ripening stage and yield was higher in melatonin treated trees than in the controls. Fruit were stored at 1 and 8 °C for 21 and 28 days, respectively. Samples were taken weekly and left at 20 °C for 1 day. Weight losses, as well as reduction in firmness and acidity, were delayed in fruits from melatonin treated trees, showing an effect of treatment on delaying the postharvest ripening process, which was attributed to a reduced ethylene production in both cultivars and at both storage temperatures. In addition, chilling injury symptoms were observed in apricots stored at 1 °C, which were reduced by preharvest melatonin treatment. Moreover, apricot from melatonin-treated fruit retained higher total phenolic content than the controls after 14 days of storage, although the phenolic profile was not affected by treatment. Thus, melatonin could be a useful tool for practical purposes to improve apricot crop yield and maintain fruit quality properties during storage. [ABSTRACT FROM AUTHOR]

Throughout history, new strategies and technologies have played a key role in promoting the development of agriculture. New strategies have led to substantial improvements in crop productivity and fruit quality. The cultivation of peach and apricot in controlled greenhouse conditions is one such strategy. The aim of the protected cultivation of these species in greenhouses is to grow fruit trees by modifying the natural environment of the tree, including the harvest duration, which can be extended. This protected cultivation should improve yield, thus increasing the benefit–cost ratio, especially in the case of organic production. Here we review the main factors involved in greenhouse fruit tree cultivation, including the planting systems and substrate, cultivar and rootstock selection, pollination management, orchard management, and environmental management. Greenhouse cultivation makes it possible to control environmental conditions like wind speed, moisture, temperature, mineral nutrients, light intensity, and the atmospheric composition, and thus gives us a better understanding of growth factor requirements, and the means to improve fruit productivity. A protected environment has been shown to be effective in maintaining a relatively high temperature and preventing leaf injury due to environmental factors, resulting in a longer period of photosynthetic activity, which increases the photosynthetic production, and is therefore a suitable alternative strategy for production in cold regions. The main benefits of apricot and peach cultivation in greenhouses are: (1) precocity; (2) high fruit quality, storage life, and market proximity; and (3) good plant health, suitable for organic cultivation. However, the main limiting factors for fruit tree production in greenhouse conditions to take into account are: (1) light scarcity at high latitudes; (2) a lack of cold for bud breaking, flowering, and fruit production; (3) potentially excessive temperatures in warm regions, which reduce the photosynthesis rate; and (4) a reduction of fruit quality, coloring, and aroma compounds in certain warm conditions with light day/night temperature variations. [ABSTRACT FROM AUTHOR]

Prunus species are important crops in temperate regions. In these regions, drought periods are predicted to occur more frequently due to climate change. In this sense, to reduce the impact of climate warming, obtaining new tolerant/resistant cultivars and rootstocks is a mandatory goal in Prunus breeding. Therefore, the current study assembled three Prunus species including almond, (P. dulcis Mill D.A. Webb), apricot (P. armeniaca L.) and peach (P. persica L.) to model the temporal effects of drought. A hybrid peach × almond and a wild almond-relative species Prunus webbii were also included in the study. Physiological traits associated with photosynthetic activity, leaf water status, and chlorophyll content were assessed under three watering treatments. Results showed that effects of time, genotype, and treatment interact significantly in all traits. In addition, results confirmed that P. webbii have a greater tolerance to drought than commercial rootstocks. However, "Real Fino" apricot showed the fastest recovery after re-irrigation while being one of the most affected cultivars. In addition, from the better response to these watering treatments by the almond genotypes, two different trends were observed after re-irrigation treatment that clearly differentiate the response of the almond cultivar "Garrigue" from the rest of Prunus genotypes. A better characterization of the short-term drought response in Prunus, an accurate and more efficient evaluation of the genotype effect was obtained from the use of mixed models considering appropriate variance–covariance structures. Although the advantages of these approaches are rarely used in Prunus breeding, these methodologies should be undertaken in the future by breeders to increase efficiency in developing new breeding materials. [ABSTRACT FROM AUTHOR]

Plum pox virus (PPV) is the most important limiting factor for apricot (Prunus armeniaca L.) production worldwide, and development of resistant cultivars has been proven to be the best solution in the long-term. However, just like in other woody species, apricot breeding is highly time and space demanding, and this is particularly true for PPV resistance phenotyping. Therefore, marker-assisted selection (MAS) may be very helpful to speed up breeding programs. Tightly linked ParPMC1 and ParPMC2, meprin and TRAF-C homology (MATH)-domain-containing genes have been proposed as host susceptibility genes required for PPV infection. Contribution of additional genes to PPV resistance cannot be discarded, but all available studies undoubtedly show a strong correlation between ParPMC2-resistant alleles (ParPMC2res) and PPV resistance. The ParPMC2res allele was shown to carry a 5-bp deletion (ParPMC2-del) within the second exon that has been characterized as a molecular marker suitable for MAS (PMC2). Based on this finding, we propose here a method for PPV resistance selection in apricot by combining high-throughput DNA extraction of 384 samples in 2 working days and the allele-specific genotyping of PMC2 on agarose gel. Moreover, the PMC2 genotype has been determined by PCR or by using whole-genome sequences (WGS) in 175 apricot accessions. These results were complemented with phenotypic and/or genotypic data available in the literature to reach a total of 325 apricot accessions. As a whole, we conclude that this is a time-efficient, cost-effective and straightforward method for PPV resistance screening that can be highly useful for apricot breeding programs. [ABSTRACT FROM AUTHOR]

In deciduous fruit species, floral bud initiation, differentiation and organogenesis take place during the summer–autumn season that precedes anthesis. Among factors able to modify the regularity of these processes, water availability represents a crucial aspect. This investigation aimed to assess the influence of different summer and autumn water deficit and re-watering treatments on floral morphogenesis, xylem vessel differentiation and quality of flower buds. Trials were carried out on two-year-old potted apricot trees (cv. 'Portici') which were submitted to different regimes: (i) fully irrigated plants; (ii) stressed plants in June (S1), July (S2) and October (S3) followed to re-watering. Midday stem water potential was used to determine water status, and leaf gas exchanges were measured during trials. Histological analyses on floral differentiation, xylem progression within flower buds and biological observations were carried out. Both summer water stress periods affected the floral differentiation leading to a temporary shutdown. The S1 trees were able to recover the development of meristematic apices while S2 had a strong delay. All drought treatments caused a slower xylem progression, variations in bud size, blooming entity and flower anomalies. Results particularly highlights the importance of water availability also in early autumn. [ABSTRACT FROM AUTHOR]

Stone fruit trees of genus Prunus, like other temperate woody species, need to accumulate a cultivar-specific amount of chilling during endodormancy, and of heat during ecodormancy to flower properly in spring. Knowing the requirements of a cultivar can be critical in determining if it can be adapted to a particular area. Growers can use this information to anticipate the future performance of their orchards and the adaptation of new cultivars to their region. In this work, the available information on chilling- and heat-requirements of almond, apricot, plum, peach, and sweet cherry cultivars is reviewed. We pay special attention to the method used for the determination of breaking dormancy, the method used to quantify chilling and heat temperatures, and the place where experiments were conducted. The results reveal different gaps in the information available, both in the lack of information of cultivars with unknown requirements and in the methodologies used. The main emerging challenges are the standardization of the conditions of each methodology and the search for biological markers for dormancy. These will help to deal with the growing number of new cultivars and the reduction of winter cold in many areas due to global warming. [ABSTRACT FROM AUTHOR]

Green peach aphid, Myzus persicae (Hemiptera: Aphididae), is an economically important pest of crops within more than 40 plant families all over the world. This study encompasses in-vitro pathogenicity of two strains of Beauveria bassiana (BB-72 and BB-252) and one strain of Lecanicillium lecanii (V-4) against green peach aphid (M. persicae). Using a leaf-dip method, three different bioassays were conducted comprised of filtrates and conidial concentrations of BB-72, BB-252 and V-4 fungal strains and their binary combinations. Infiltrate bioassays, 2 mL fungal filtrate of each strain was used. In conidial bioassays, three different concentrations (i.e., 1 × 106, 1 × 107 and 1 × 108 conidia mL−1) of each fungal strain were used, while in binary combination bioassays, LC50 and LC33 of these fungal strains were evaluated. According to the results, maximum pathogenicity against test aphids was observed at 10th day of all treatments. Both strains of B. bassiana (BB-72 and BB-252) exhibited higher mortality of aphids (up to 95 and 91%, respectively) than L. lecanii (V-4) strain (87%) in all three types of bioassays. Moreover, binary combinations of BB-72 and BB-252 strains showed significantly higher aphid mortality (94%) than other combinations. Reduced mortality in case of fungal combinations of V-4 strain might be due to the antagonistic effect of L. lecanii strain along with both strains of B. bassiana. Nevertheless, evaluation of combined pathogenicity of the fungal strains constitutes the novelty of this in-vitro study which revealed that both strains of B. bassiana (i.e., BB-72 and BB-252) are mutually compatible and can be utilized together as new biocontrol tools against destructive insect pests such as M. persicae. [ABSTRACT FROM AUTHOR]