Fruit Set Research Articles

Improving mangoes' productivity and crop water productivity by 24-epibrassinosteroids and hydrogen peroxide under deficit irrigation

In nature, plants are frequently subjected to a wide range of abiotic stresses that drastically reduce crop productivity. Deficit in irrigation is one of the main factors of abiotic stresses that affect agricultural productivity. Nevertheless, not much research has been done on how to use water with brassinosteroids (Br) and hydrogen peroxide (H2O2)in deficit water conditions in order to reach comparatively good values of mango tree growth, productivity, and fruit quality as well as crop water productivity (WPC). A split-plot experiment in a complete randomized block system design study with 3 regulated deficit irrigation levels i.e. 100% IR (Irrigation requirement), 80% IR, and 60% IR was implemented in 2022 and 2023, each irrigation regime was combined with the foliar application of distilled water (control), 1 mg/L Br, 10 mM H2O2, 1 mg/L Br + 10 mM H2O2. Foliar treatments were applied at 3 different phenological stages: flower bud induction and differentiation, full bloom, and beginning of fruit set. The results showed that fruit shape index and acidity significantly improved as irrigation volume increased, however, the proportion of fruit mineral content and fruit chemical characteristics was inversely correlated with the volume of water. Meanwhile, moderate regular deficit irrigation (80% IR) achieved marked increases in leaf minerals and total chlorophyll content, fruit quality, yield, and water use efficiency. Drought stress (60% IR) significantly decreased fruit set, fruit retention, yield traits, and fruit physical and chemical properties, at the same time, significant improvements in the content of stress indicators (proline, total phenols, and carotenoids) were observed compared with control. All treatments with Br and H2O2 alone or in combination under drought stress had a pronounced effect in this regard. Overall, foliar spray of 1 mg/L Br+10 mM H2O2 was the most powerful treatment that emended the unpropitious effect of water stress.

Effect of Foliar Application of Nano Urea, Boron and Zinc Sulphate on Growth, Yield and Quality of Guava (Psidium guajava L.) cv. Allahabad Surkha

The present experiment entitled “Effect of Foliar Application of Nano Urea, Boron and Zinc Sulphate on Growth, Yield and Quality of Guava (Psidium guajava L.) cv. Allahabad Surkha” was conducted at Department of Horticulture, Naini Agricultural Institute, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj during the session 2022 - 2024. The experiment was laid out in randomized block design with three replications, and the study consists of ten treatment combinations including control. The best treatment was T9 (Nano urea 2.0% + zinc sulphate 0.6% + boron 0.6%) & T8 (Nano urea 2.0% + zinc sulphate 0.4% + boron 0.4%) which shows the highest values in all the parameters viz., number of flower/tree (86.47), Days taken to fruit harvesting (49.19), fruit set (74.00%), Number fruit/tree (63.25), Fruit length (7.42 cm), fruit weight (178.73g), fruit diameter (7.12 cm), fruit yield/tree (11.29 kg). Increased flowering, fruit yield and quality might be due to the increased absorption of nutrients when given as foliar application.

Fine-grained recognition of bitter gourd maturity based on Improved YOLOv5-seg model

Bitter gourd, being perishable, requires timely harvesting. Delayed harvesting can result in a substantial reduction in fruit quality. while premature harvesting leads to underdeveloped fruit and decreased yields, the continuous flowering pattern in bitter gourd underscores the significance of accurately assessing fruit growth and ensuring timely harvesting for subsequent fruit setting and development. The current reliance on the experience of production personnel represents a substantial inefficiency. We present an improved real-time instance segmentation model based on YOLOv5-seg. The utilization of dynamic snake convolution enables the extraction of morphological features from the curved and elongated structure of bitter gourd. Diverse branch blocks enhance feature space diversity without inflating model size and inference time, contributing to improved recognition of expansion stages during bitter gourd growth. Additionally, the introduction of Focal-EIOU loss accurately locates the boundary box and mask, addressing sample imbalances in the L2 stage. Experimental results showcase remarkable accuracy rates of 99.3%, 93.8%, and 98.3% for L1, L2, and L3 stages using mAP@0.5. In comparison, our model outperforms other case segmentation models, excelling in both detection accuracy and inference speed. The improved YOLOv5-seg model demonstrates strong performance in fine-grained recognition of bitter gourd during the expansion stage. It efficiently segments bitter gourd in real-time under varying lighting and occlusion conditions, providing crucial maturity information. This model offers reliable insights for agricultural workers, facilitating precise harvesting decisions.

Pollination by birds, non-flying mammals, and European honeybees in a heathland shrub, Banksia catoglypta (Proteaceae)

Abstract Vertebrate pollination has evolved in many plant lineages, with pollination by birds the most prevalent strategy. However, in Banksia (Proteaceae) many species are visited by a combination of nectarivorous birds, non-flying mammals (NFMs), and insects, though the relative importance of these pollen vectors for reproduction remains poorly understood. Here, we investigate the contribution to fruit set of birds, NFMs, and insects in Banksia catoglypta—a heathland shrub from south-west Australia. This species flowers in winter and produces large, golden-yellow inflorescences that are typically presented near the ground and consist of rigid, strongly scented flowers with a long stigma-nectary distance—suggesting pollination by vertebrates. The primary floral visitors were white-cheeked honeyeaters (Phylidonyris niger), honey possums (Tarsipes rostratus), house mice (Mus musculus), and introduced European honeybees (Apis mellifera), all of which carried B. catoglypta pollen. Banksia catoglypta was found to be obligately outcrossing with no evidence of pollen limitation. Selective exclusion of flying pollinators revealed that inflorescences pollinated solely by NFMs produced 50% fewer fruit than open-pollinated controls. Therefore, while mammals are pollinators of B. catoglypta, they may contribute comparatively little to fruit set in some Banksia species displaying floral traits considered adaptations to NFM pollination. Exclusion of vertebrate pollinators had no effect on fruit set, demonstrating that European honeybees can be effective pollinators of some primarily vertebrate-pollinated plants.

Pollinator shift ensures reproductive success in a camouflaged alpine plant.

There are intrinsic conflicts between signalling to mutualists and concealing (camouflaging) from antagonists. Like animals, plants also use camouflage as a defence against herbivores. However, this can potentially reduce their attractiveness to pollinators. Using Fritillaria delavayi, an alpine camouflaged plant with inter-population floral colour divergence, we tested the influence of floral trait differences on reproduction. We conducted pollination experiments, measured floral morphological characteristics, estimated floral colours perceived by pollinators, analysed floral scent, and investigated the reproductive successes in five populations. We found that the reproduction of F. delavayi depends on pollinators. Under natural conditions, a flower-camouflaged population had a 100% fruit set and similar seed set to three out of four yellow-flowered populations. Bumblebees are important pollinators in the visually conspicuous yellow-flowered populations, whereas flies are the only pollinator in the flower-camouflaged population, visiting flowers more frequently than bumblebees. The camouflaged flowers cannot be discriminated from the rock background as perceived by pollinators, but may be located by flies through olfactory cues. Collectively, our results demonstrate that the flower-camouflaged population has different reproductive traits from the visually conspicuous yellow-flowered ones. A pollinator shift from bumblebees to flies, combined with high visitation frequency, compensates the attractiveness disadvantage in camouflaged plants.

Ecological perspectives on female and male reproductive success with competition in two Serapias species.

The deceptive strategies by which orchids are pollinated and how these are capable of attracting pollinators remain understudied with regard to their implications on plant fitness. Despite its ecological importance, limited investigations have been conducted on sexual deception and shelter mimicry in orchid species, making it a compelling avenue in orchid biology research. To expand the knowledge of these reproductive mechanisms, we studied the pollination of Serapias lingua and S. parviflora, in co-occurring and isolated sites in Balearic Islands (Spain), further accentuated by the presence of a hybrid, indicating shared pollinators. We employed bagging and hand pollination experiments to examine their reproductive biology. Furthermore, we evaluated the influence of phenotypical and ecological factors on reproductive success, including biometric measurements, reproductive performance and neighborhood diversity (co-flowering and pollinator communities). Reproductive mechanisms between these two orchid species exhibit substantial disparities. Serapias lingua relies primarily on insect-mediated pollination, while S. parviflora demonstrates self-reproduction capacity. Although events of open pollination are rare, hybridization occurs predominantly when S. lingua is the pollen donor. Fruit set in S. parviflora was positively correlated with plant height, while in S. lingua it was negatively associated with flower size. The coexistence of both species positively affected pollinia removal in S. parviflora, but did not exert an influence on reproductive traits in S. lingua. Overall, biometric parameters were diminished in isolated compared to co-occurring sites. At the community level, the increased diversity of co-flowering species in the vicinity exhibited an inhibitory effect on pollinia removal in S. parviflora. Under a context of pollinator loss or phenological mismatch between pollinator presence and flowering, the selfing capacity of S. parviflora would guarantee reproduction whereas S. lingua survival would be compromised. Furthers studies are needed to assess the effects of phenotypical and ecological factors on reproductive success of S. lingua in pollinator-decline scenarios.

Harmful self-pollination drives gynodioecy in European chestnut, a self-incompatible tree.

Gynodioecy is a rare sexual system in which two genders (sensu Lloyd, 1980), cosexuals and females, coexist. To survive, female plants must compensate for their lack of siring capacity and male attractiveness. In European chestnut (Castanea sativa), an outcrossing tree, self-pollination reduces fruit set in cosexual individuals because of late-acting self-incompatibility and early inbreeding depression. Could this negative sexual interaction explain the presence of females in this species? We studied gender variation in wild populations of European chestnut. In addition, we compared fruit set (the proportion of flowers giving fruits) and other key female fitness components as well as reproductive allocation between genders. We then performed emasculation experiments in cosexual trees, by removing nectar-producing fertile male inflorescences. We also removed sterile but nectar-producing male inflorescences from female trees, as a control. We found a highly variable proportion of male-sterile individuals in the wild in European chestnut. In the experimental plot, trees from each gender had similar size, flower density, and burr set, but different fruit set. Removing nectar-producing male inflorescences from branches or entire trees increased fruit set in cosexual but not in female trees. These results show that self-pollination impairs fruit set in cosexual trees. Female trees avoid these problems as they do not produce pollen but continue to attract pollinators thanks to their rewarding male-sterile inflorescences, resulting in a much higher fruit set than in cosexuals. This demonstrates that even outcrossed plants can benefit from the cessation of self-pollination, to the point that unisexuality can evolve.

Synergistic effect of seaweed extract and boric acid and/or calcium chloride on productivity and physico-chemical properties of Valencia orange.

Many citrus species and cultivars are grown successfully in tropical and subtropical countries, as well as in arid and semi-arid regions with low levels of organic matter and low cation exchange, resulting in lower nutrient uptake by the plant. The essential nutrients needed for citrus flowering and fruit set are limited in winter due to a reduction in transpiration rate, negatively effecting vegetative growth, flowering, yield, and fruit quality. The present investigation was carried out to assess the nutritional status, fruit yield parameters, and fruit quality of Valencia orange trees after foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations in the 2020/2021 and 2021/2022 seasons. The treatments were arranged in a split-plot design (three levels spraying seaweed extract × four levels spraying calcium chloride and boric acid and their combinations × four replicates × one tree/replicate). The results indicated that all of the characteristics measured, including leaf chlorophyll, leaf mineral contents, fruit yield parameters, fruit physical properties, and fruit chemical properties, were significantly affected by the foliar spraying of seaweed extract (SW) combined with calcium chloride and boric acid and their combinations. Although all treatments increased the productivity and the physical and chemical properties of Valencia orange fruits compared to the control, a treatment of 10 g/L SW combined with 0.5 g/L boric acid and 1 g/L calcium chloride produced superior results. This ratio of SW, boric acid, and calcium chloride is therefore recommended to enhance productivity and improve the physico-chemical properties of Valencia orange for greater fruit yield.

The prospects of intercropping of brinjal (Solanum melongena L.) with other vegetables on sorjan system in vulnerable southern coastal saline and non-saline areas of Bangladesh

The demand for food in Bangladesh is increasing due to the increasing population. Land is the primary natural resource that affords habitat and sustenance for living beings. In Bangladesh, the coastal areas cover an area of 47,201 km2 or 32 % of the total land under 19 districts of Bangladesh. The coastal southern saline and non-saline areas are vulnerable to water logging conditions and farmers cannot grow any crops except dry season (rabi). However, in some areas, farmers are trying to use their indigenous technologies to combat natural disasters to ensure food security. For example, floating, sorjan or raised bed systems are potential and farmers are practicing in these areas. Among these techniques, the sorjan bed system is one of the potential techniques that is extensively used in southern Bangladesh, particularly water logging conditions to improve food security. To enhance the production and make land cultivation profitable, the experiments were carried out at the farmers’ fields under the sorjan system in consecutive two growing seasons. The sole crop was brinjal (cv. BARI Begun-12), BARI Lalshak-1 (cv. Red amaranth), BARI Dhania-1 (cv. Coriander leaf), Cauliflower (cv. Cold queen), Cabbage (cv. Equatoria) and Knol Khol were utilized as intercropping with brinjal. The treatments were i) Sole brinjal, ii) Brinjal + Red amaranth, iii) Brinjal + Coriander leaf, iv) Brinjal + Cauliflower, v) Brinjal + Cabbage, and vi) Brinjal +. 24-day-old seedlings of the BARI Begun-12 grown in a nursery bed were transferred to the plots where the seeds of Red amaranth and Coriander leaf were directly sown. However, the seedlings of Cauliflower, Cabbage, and Knol Khol were also transplanted to the field after one week of transplanting brinjal. The results exposed that sole crops had the highest results in terms of days to flowering, days to first fruit set, days to first harvesting, leaf area, fruit length, fruit breadth, single fruit weight, fruits plant−1, fruit yield, TSS %, and dry matter %. In both years, brinjal exhibited the highest yield as the sole crop compared to intercropping. 48.12 t/ha and 46.27 t/ha in the first and second cropping seasons, respectively. In the first cropping season, Red amaranth, Coriander leaf, Cauliflower, Cabbage, and Knol Khol performed with a yield of 10.12, 7.23, 23.14, 22.87, and 9.05 t/ha. During the second cropping season, the same crops exhibited a yield of 10.05, 7.01, 23.09, 22.68, and 9.98 t/ha. The highest land equivalent ratio, gross return, net return, and BCR were obtained from brinjal-cauliflower intercropping, which was 1.74, 1049300 BDT, 553820 BDT, and 2.12, respectively, in the 2021–2022 cropping season and 1.78, 1057900 BDT, 562010 BDT, and 2.13, respectively, in the next season in 2022–2023. This intercropping approach resulted in a higher land equivalent ratio, net return, and benefit-cost ratio of 1.76, 557915 BDT, and 2.125, respectively, over the average of two successive cropping seasons.

Identification of Key Genes of Fruit Shape Variation in Jujube with Integrating Elliptic Fourier Descriptors and Transcriptome.

Jujube (Ziziphus jujuba) exhibits a rich diversity in fruit shape, with natural occurrences of gourd-like, flattened, and other special shapes. Despite the ongoing research into fruit shape, studies integrating elliptical Fourier descriptors (EFDs) with both Short Time-series Expression Miner (STEM) and weighted gene co-expression network analysis (WGCNA) for gene discovery remain scarce. In this study, six cultivars of jujube fruits with distinct shapes were selected, and samples were collected from the fruit set period to the white mature stage across five time points for shape analysis and transcriptome studies. By combining EFDs with WGCNA and STEM, the study aimed to identify the critical periods and key genes involved in the formation of jujube fruit shape. The findings indicated that the D25 (25 days after flowering) is crucial for the development of jujube fruit shape. Moreover, ZjAGL80, ZjABI3, and eight other genes have been implicated to regulate the shape development of jujubes at different periods of fruit development, through seed development and fruit development pathway. In this research, EFDs were employed to precisely delineate the shape of jujube fruits. This approach, in conjunction with transcriptome, enhanced the precision of gene identification, and offered an innovative methodology for fruit shape analysis. This integration facilitates the advancement of research into the morphological characteristics of plant fruits, underpinning the development of a refined framework for the genetic underpinnings of fruit shape variation.

Demonstration of Integrated Nutrient Management Practices on Yield, Yield Attributes and Economics of Pomegranate (cv. Bhagwa) in Arid Zone of Andhra Pradesh

Integrated Nutrient Management (INM) demonstrations on pomegranate were conducted in 20 farmer fields in Krishi Vigyan Kendra, Kalyandurg-operated mandals of Ananthapur district in Andhra Pradesh state during 2022-23 and 2023-24. The aim was to demonstrate the influence of INM practice on enhancing yield attributing features, yield and economics in farmer fields. According to the data, INM practice resulted in a larger number of flowers/plants, fruits/plant, fruit setting percentage, average fruit weight and yield/plant than farmer’s practice, who used chemical nutrient management alone. The demonstration of INM practice resulted in 11.56% and 10.52% higher fruit output than farmers' practices in 2022-23 and 2023-24, respectively. The enhanced yield in INM practice can be attributed to more fruits per plant and heavier fruit weight. INM approaches also provided a greater economic advantage, and their adoption resulted in a better benefit-cost ratio (5.87) than farmers' use of inorganic nutrient management (5.40). From the findings It can be concluded that, under current circumstances, adopting INM practices in pomegranate cultivation could result in a higher economic benefit than farmers' practices, encouraging more farmers to adopt INM practices not only in pomegranate but also in other major fruit crops in Ananthapur district of Andhra Pradesh.

Spacing and Tomatotone Influence on Yield of Rain Fed Tomato (Solanum lycopersicum L.) in Sudan Savanna of Nigeria

Some scientific reports indicated that Tomatotone (4-Chlorophenoxy acetic acid (4-CPA) is one of the plant hormones that can be used to increase fruit setting and yield of tomato. The aim of the research is to evaluate the efficacy of 4-chlorophenoxy acetic acid at different plant population density. Field trials were therefore conducted during the rainy season of 2020 at two locations. The treatments consisted of three population density (22,222, 26,666 and 33,333) and four concentrations of 4-CPA (0, 50, 75 and 100 mgL-1 of distilled water). The experiment was laid out in a Complete Randomized Block Design and replicated three times. The data collected on yield and yield components were subjected to analysis of variance. The result showed that 4-CPA had a significant effect on fruit length, fruit weight, marketable fruit yield and total fruit yield. Plant population density was obtained also to have significantly influenced total fruit yield and marketable fruit yield. Based on the results of the study, it could be suggested that farmers in the areas of study can be advised to grow UC82B tomato and apply 4-CPA at a density of 22,222 plants ha-1 for higher yield of the crop during rainy season

Effects of artificial pollination and herbivore exclusion on the fruit set and seed production of the golden orchid Cephalanthera falcata in Japan

Effects of artificial pollination and herbivore exclusion on the fruit set and seed production of the golden orchid Cephalanthera falcata in Japan

Assessing the Impact of Genotype-Specific Caprifig Fruit Storage on the Pollination Efficacy and Fruit Quality of “Bursa Siyahı” Cultivar: A Multivariate Analysis Approach

Fig types such as “Smyrna” and “San Pedro” require pollination (called caprification in fig cultivation) to produce a commercial crop, based on the crop and pollination characteristics of figs. Caprification is the process of hanging caprifig (male fig) fruits on female fig trees to ensure the transfer of pollen from the female fig to the caprifig by a wasp (Blastophaga psenes) that lives within the caprifig. It is necessary to extend the caprification period by using caprifig genotypes that ripen at different times, as female fig fruits ripen gradually. However, as caprifigs may not be continuously available for pollinating female figs, storing suitable caprifigs is necessary. The aim of this study was to assess changes in Blastophaga psenes, the duration of Blastophaga’s exit, and the viability of pollen from caprifigs of different genotypes (16 08 05, 16 08 09, 16 08 10, 16 09 10, and 16 ZF 08) stored for caprification. These stored caprifig genotypes were subsequently used for pollination three times at 8-day intervals, after which their impact on the set and quality of the edible fig fruits was evaluated. According to the average data, at the end of storage, the least B.psenes loss was obtained from the 16 08 05 (61.03%) genotype, and the highest was obtained from the 16 09 10 (67.00%) genotype. Pollen germination tended to increase with the storage of caprifig fruits, but this increase was not linear. After storage, the 16 08 09 and 16 09 10 genotypes exhibited greater pollen germination. The highest fruit set and quality were obtained when the 16 08 09 and 16 09 10 genotypes were used as pollen sources. Furthermore, since the 16 08 10 genotype is the latest ripening caprifig genotype, it has been determined that it can pollinate late-ripening “Bursa Siyahı” fruits. Principal component and path analysis demonstrated that pollen viability and germination rate were crucial in selecting caprifig genotypes for fruit set and quality.

Identifying the sensory profiles of naturally fermented table olives and their application to industrially processed cultivars

The study examines the sensory profile of industrially processed, naturally fermented table olives. A detailed set of descriptors crunchiness, hardness, bitter, fibrousness, saltiness, chewiness, sourness, green fruit, ripe fruit, flesh/stone separation, piquant, and musty was developed for green and turning colour Manzanilla and Gordal products, using Quantitative Descriptive Analysis (QDA). Green Gordal (GG) was characterised by higher than average chewiness (scores 7.0-7.1), crunchiness (7.5-8.2), hardness (scores 7.7-8.0) and fibrousness (6.2-6.4). In contrast, turning colour Gordal was lower than average in bitter (2.9-3.4), crunchiness (4.1-4.9), hardness (4.5-5.1) and fibrousness (4.4-4.7). Initially, the green Manzanilla was characterised by higher than average levels of bitter (6.5-7.1), crunchiness (7.2-7.4), hardness (6.9-7.0), and saltiness (3.2-3.3). However, they diminished to about average levels by the end of the fermentation process. The turning colour Manzanilla was initially associated with elevated bitter (5.6-5.9) and lower-than-average final crunchiness (4.6-4.9), hardness (5.1-5.7) and fibrousness. However, the final product resulting from this treatment had relatively high significant values for acetic/vinegar (3.52), astringent (3.5), musty (2.00), piquant (2.5), rancid (1.84) and ripe fruit flavour (3.25). The Hotelling T2 test, PCA, and the correlation circle reinforced the specific sensory profile associated with cultivars and maturation stages. Minimal changes were observed over time. PLS-R revealed associations between physicochemical characteristics and sensory profiles such as bitter with phenol content (standardised coefficient; 0.881) and texture (0.755) or ripe fruit with bitter index (0.475), among others.

Growth and yield response of Tanjung II and Unpad CB2 red chili varieties grown in the medium land

Red chili is an important commodity that is daily needed by the community. Non-central chili areas often experience deficits due to the high consumption volume and low productivity of chili peppers. To increase the productivity of chili in non-central areas, expand it in the medium land. This study aims to determine the productivity of two introduced chili varieties in the medium land whose adaptation areas came from lowland and highland areas. This study was analyzed using an independent sample T-test at a significant level of 5%. The results of the data analysis showed that the Tanjung II variety significantly influenced the parameters of stem diameter and weight of the fruit. Meanwhile, the Unpad CB2 variety significantly influences the parameters of plant height, number of leaves, number of flowers, number of fruits, and fruit set. However, both varieties have no noticeable effect on the weight parameters of the cropping fruit and potential yield in hectares. The Tanjung II variety experienced a decrease in yield by 54.58%, while the Unpad CB2 variety was 53.56%.

Genetic and molecular regulation of chilling requirements in pear: breeding for climate change resilience.

Pear (Pyrus spp.) is a deciduous fruit tree that requires exposure to sufficient chilling hours during the winter to establish dormancy, followed by favorable heat conditions during the spring for normal vegetative and floral budbreak. In contrast to most temperate woody species, apples and pears of the Rosaceae family are insensitive to photoperiod, and low temperature is the major factor that induces growth cessation and dormancy. Most European pear (Pyrus Communis L.) cultivars need to be grown in regions with high chilling unit (CU) accumulation to ensure early vegetative budbreak. Adequate vegetative budbreak time will ensure suitable metabolite accumulation, such as sugars, to support fruit set and vegetative development, providing the necessary metabolites for optimal fruit set and development. Many regions that were suitable for pear production suffer from a reduction in CU accumulation. According to climate prediction models, many temperate regions currently suitable for pear cultivation will experience a similar accumulation of CUs as observed in Mediterranean regions. Consequently, the Mediterranean region can serve as a suitable location for conducting pear breeding trials aimed at developing cultivars that will thrive in temperate regions in the decades to come. Due to recent climatic changes, bud dormancy attracts more attention, and several studies have been carried out aiming to discover the genetic and physiological factors associated with dormancy in deciduous fruit trees, including pears, along with their related biosynthetic pathways. In this review, current knowledge of the genetic mechanisms associated with bud dormancy in European pear and other Pyrus species is summarized, along with metabolites and physiological factors affecting dormancy establishment and release and chilling requirement determination. The genetic and physiological insights gained into the factors regulating pear dormancy phase transition and determining chilling requirements can accelerate the development of new pear cultivars better suited to both current and predicted future climatic conditions.

Olive (Olea europaea L.) reproductive biology: implications for yield, compatibility conundrum, environmental constraints.

Olive (Olea europaea L.) is an important Mediterranean tree species with a longstanding history of cultivation, boasting a diverse array of local cultivars. While traditional olive orchards are valued for their cultural and aesthetic significance, they often face economic sustainability challenges in the modern context. The success of both traditional and newly introduced cultivars (e.g. those obtained by crossbreeding) is hindered by self-incompatibility, a prevalent issue for this species that results in low fruit set when limited genetic diversity is present. Further, biological, environmental, and agronomic factors have been shown to interlink in shaping fertilization patterns, hence impacting on the final yield. Climatic conditions during pollination, such as excessive rainfall or high temperatures, can further exacerbate the problem. In this work, we provide an overview of the various complex and multifaceted factors that trigger the phenomenon of sub-optimal fruit set in olive trees. Through this work, we aim to provide a comprehensive understanding of the interplay among these factors, shedding light on potential mechanisms and pathways that contribute to the observed outcomes in the context of self-incompatibility of olive. This review aims to contribute to the development of sustainable olive production systems and the preservation of this vital component of Mediterranean culture.

Pollination deficits and their relation with insect pollinator visitation are cultivar-dependent in an entomophilous crop

Insects contribute considerably to global crop pollination, with pollination deficits being documented for multiple entomophilous or pollinator-dependent crops. Different cultivars of crops are being cultivated within and across production regions, so it is essential to understand the cultivar variability of pollination deficits. Here, we used a dataset from 286 sites from multiple production regions to develop a synthesis on pollination deficits in two widely cultivated highbush blueberry cultivars, ‘Bluecrop’ and ‘Duke’. Additionally, we determined if bee visitation or bee richness reduces pollination deficits in these cultivars. On average, neither cultivar showed pollination deficits regarding fruit set. However, for ‘Bluecrop’ we found pollination deficits for berry weight and seed set, which was not the case for ‘Duke’. Increasing total bee visitation reduced pollination deficits of both berry weight and seed set for ‘Bluecrop’. More specifically, a non-linear, negative exponential model best predicted this relation between bee visitation and pollination deficits. Our results highlight that pollination deficits and responses to pollinator visitation are variable between different cultivars of a single crop, which suggests opportunities to use certain cultivars that are less dependent on insect-mediated pollination in landscapes and regions where pollination services have been compromised. In addition, the non-linear response between bee visitation and pollination deficits suggests that optimal bee visitation rates need to be determined to improve pollination management and crop yield and to support accurate economic valuations of pollination services.

Effect of Foliar Application of Potassium Fertilizer on Yield, Fruit Quality, and Cold Hardiness of Vitis spp. ‘Chambourcin’

ABSTRACT Temperate regions experiencing sub-zero temperatures negatively impact grapevine yield. Potassium has been claimed as a cryoprotectant to improve cold hardiness in grapevine. This study investigated the effect of foliar application of liquid potassium-based fertilizer, ReaXTM, on cold-hardiness of grapevine Vitis spp. “Chambourcin” along with its effect on yield and fruit quality. The vines were sprayed four to five times between the fruit set and veraison stage at a concentration of 1.5% (v/v) for two consecutive seasons. Petioles were analyzed for nutrients, clusters for yield and fruit quality, and cold hardiness was determined by differential thermal analysis and bud injury assessment. Potassium deficiency was observed in all treatments, and its content did not increase significantly in treated vines. Berry potassium levels and total soluble solids were generally higher in K-treated vines, however, there was no significant effect on yield and other fruit quality traits. Significant differences in cold hardiness levels were observed in both dormant seasons. Foliar application of potassium is a promising cultural practice to increase cold hardiness, but further studies are needed to understand the limits of its effectiveness.