•Quality is one word with different meanings.•Appearance of fresh fruit is the first purchasing-driving trait.•Environmental factors strongly affect external and internal fruit quality.•Orchard ...design and management techniques can impact fruit quality.•All parameters defining quality can be measured to describe apples.
Apple is the fourth most important fruit produced and eaten around the world with a production of 84 million tonnes in 2014. The modern cultivated apple (Malus × domestica Borkh) is probably the result of interspecific hybridization and, at the moment, ten thousand or more apple cultivars are listed in the European Apple Inventory. The large number of cultivars reflects also a broad range of variability in the quality traits. “Fruit quality” is a dynamic concept changing on the basis of the consumer needs and perceptions that reflect sociocultural evolution. Almost all the characteristics determining apple quality can be measured or classified. Consumers assess apples by its appearance (colour, size, shape, absence of defects) and then by its eating quality, although the latter may determine the willingness to buy the product again. Furthermore, the high level of polyphenols confer apples relevant nutraceutical properties. Apple consumption has been deeply encouraged and a broad range of varieties are competing in the market, but the indisputable quality of a commodity is proved by the repeating purchase by consumers. In this review, the most common worldwide utilized external and internal quality parameters (i.e. firmness, starch, soluble solid content, titratable acidity) and conventional techniques as well as some new approaches to assess them are explored. New quality metrics recently developed, like IAD and dry matter, are discussed too. The current review discusses the impacts and potentials of both environmental conditions, and agronomic factors. Environmental and agronomic factors along all the growing season strongly affect the final apple quality including the nutraceutical aspects. Temperature and light contribute to several modifications of external and internal apple quality like red overcolor and dry matter accumulation, but also can trigger unwelcome disorders like sunburn. Orchard design, training system and pruning can dramatically impact the skin overcolor and the maturity of the fruit. Crop load and thinning can determine physiological adjustments that benefit the dry matter accumulation in the fruit. Irrigation and nutrition can modified the overcolor and the chemical composition of the flesh.
In 2018, 23.2 Mt of pears were produced in the world across 1.3 million hectares (ha) of cultivated land. This review analyzes different training systems and management styles that have been adopted ...worldwide, emphasizing the European pear’s economic and environmental sustainability for the Mediterranean area of cultivation. Despite a reduced number of cultivars utilized around the world, pear presents a plethora of innovative training systems. In Europe, dwarfing rootstocks have led to reduced planting distances and a subsequent increase in planting density. Still, the economic sustainability of these systems is now questionable. Many of the quince rootstocks have made it possible to considerably reduce the size of the tree and introduce the concept of continuous row planting, with the management of orchards from the ground (i.e., pedestrian orchard). The planting distance must be chosen according to the soil fertility, the vigor of the grafting combination, and the training system. The planting distance dramatically affects the pruning and the management of soil, fertilization, and irrigation. The reduction of tree size also lowers the volume of spray necessary when applying pesticides. The variability in yield worldwide results from the interaction amongst cultivar/rootstock/training system/climate/management.
As apple orchards have transitioned to high-density plantings, proper training systems are required to manage increased leaf area. Leaf area index (LAI) is defined as the ratio between leaf area to ...ground area (m2/m2) and can infer orchard health, light relationships and productivity. New technologies enable rapid assessments of LAI and light interception (LI) in the orchard. In this study, LAI, LI, and productivity were assessed across two training systems (Spindle and V), two rootstocks (Geneva 41® (G41) and Malling 9—Nic29 (Nic29)) and two pruning techniques (“click” and bending) in 2016 and 2017. The objective of this study was to determine a management strategy for “WA38” to meet optimal levels for LAI (1.2–2.0) and light interception (65–75%). Higher light interception was measured in V compared to Spindle and in G41 compared to Nic29 in both years. Minimal differences in LAI and light interception were detected across pruning techniques. In “WA38” the “click” technique maintained more consistent yields than bending. In both years, the Spindle-Nic29-“click” combination maintained optimal thresholds for LAI (1.93 and 1.48), light interception (66% and 68%) and consistent yields. This sequence helps mitigate “blind wood” and alternate bearing, while optimizing leaf area and light in “WA38”.
Crop load management is growing increasingly important as a factor related to biennial tendencies, post-harvest disorders, and inconsistent fruit quality in apples like “Honeycrisp”. Washington State ...University released a new apple cultivar, called “WA38”, in 2017. Limited literature is available about the productive characteristics of this new cultivar. An experimental trial evaluating the effect of crop load on leaf area, fruit quality, mineral composition, and return bloom of “WA 38” was conducted for two consecutive years (2017 and 2018) to determine an optimal crop load. Trees were trained as a spindle and grafted on Malling-9 Nic29 (Nic29) rootstocks. Crop loads were adjusted to 2, 4, 6, and 8 fruits/cm2 of trunk cross-sectional area (TCSA). Crop load had a significant effect on production, with yields ranging from 28 to 83 MT/ha in 2017. Fruit quality was impacted by increasing crop load, with a reduction in fruit weight, soluble solid content, firmness, dry matter, titratable acidity, and a delay in maturity. Leaf-to-fruit ratios were higher in lower crop loads. Relatively consistent flower bud formation was seen at the 6 and 8 fruits/cm2 categories. A possible threshold for optimal fruit quality and consistent bloom was identified around 6 fruits/cm2 TCSA.
A pre-harvest apple (Malus × domestica Borkh.) disorder named “green spot” (GS) was recently identified on ‘WA 38’ apples. Previous work indicated a tentative association between GS and fruit mineral ...imbalance, and an influence of rootstock selection on GS frequency; however, the specific causes, risk factors, and mitigation steps have not been explored. In this study, the role of microclimate, modified using netting or fruit bagging, on GS incidence in ‘WA 38’ apples over two years on two different dwarfing rootstocks, ‘Geneva 41’ (‘G.41’) and ‘Malling 9-Nic29’ (‘M.9’), was investigated. Early season fruit bagging reduced GS appearance, but netting showed mixed results between year and rootstock. Rootstock selection influenced GS incidence, especially in the 2021 season. Fruit mineral analyses highlighted some differences of mineral composition between symptomatic and asymptomatic apples, which helped to corroborate earlier reports; however, within the full context of these results, it is not clear that nutrient imbalance directly influences disorder incidence. Further work to understand the mechanisms behind GS emergence should consider environmental factors, including light, humidity, and wind, as well as anatomical features of ‘WA 38’ fruit, such as lenticel morphology and physiology.
Inconsistent pear fruit ripening resulting from variable harvest maturity within tree canopies can contribute to postharvest losses through senescence and spoilage that would otherwise be effectively ...managed using crop protectant and storage regimes. Because those inconsistencies are likely based on metabolic differences, non-targeted metabolic profiling peel of 'd'Anjou' pears harvested from the external or internal canopy was used to determine the breadth of difference and link metabolites with canopy position during long-term controlled atmosphere storage.
Differences were widespread, encompassing everything from expected distinctions in flavonol glycoside levels between peel of fruit from external and internal canopy positions to increased aroma volatile production and sucrose hydrolysis with ripening. Some of the most substantial differences were in levels of triterpene and phenolic peel cuticle components among which acyl esters of ursolic acid and fatty acyl esters of p-coumaryl alcohol were higher in the cuticle of fruit from external tree positions, and acyl esters of α-amyrin were elevated in peel of fruit from internal positions. Possibly the most substantial dissimilarities were those that were directly related to fruit quality. Phytosterol conjugates and sesquiterpenes related to elevated superficial scald risk were higher in pears from external positions which were to be potentially rendered unmarketable by superficial scald. Other metabolites associated with fruit aroma and flavor became more prevalent in external fruit peel as ripening progressed and, likewise, with differential soluble solids and ethylene levels, suggesting the final product not only ripens differentially but the final fruit quality following ripening is actually different based on the tree position.
Given the impact tree position appears to have on the most intrinsic aspects of ripening and quality, every supply chain management strategy would likely lead to diverse storage outcomes among fruit from most orchards, especially those with large canopies. Metabolites consistently associated with peel of fruit from a particular canopy position may provide targets for non-destructive pre-storage sorting used to reduce losses contributed by this inconsistency.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The rising interest in beneficial health properties of polyphenol compounds in fruit initiated this investigation about biochemical composition in peach mesocarp/exocarp. Biochemical evaluation of ...phenolic compounds and ascorbic acid were quantified through high-performance liquid chromatography (HPLC) in relation to three flesh colors (white, yellow and red) and four flesh typologies (melting, non-melting, slow softening and stony hard) within six commercial cultivars and eight breeding selections of peach/nectarine in 2007. While in 2008, quality and sensorial analyses were conducted on only three commercial cultivars (‘Big Top’, ‘Springcrest’ and ‘Ghiaccio 1’). The red flesh selection demonstrated the highest levels of phenolic compounds (in mesocarp/exocarp) and ascorbic acid. Total phenolic concentration was approximately three-fold higher in the exocarp than the mesocarp across all accessions. Breeding selections generally reported higher levels of phenolics than commercial cultivars. Flesh textural typologies justified firmness differences at harvest, but minimally addressed variations in quality and phenolic compounds. Flesh pigmentation explained variation in the biochemical composition, with the red flesh accession characterized by an abundancy of phenolic compounds and a high potential for elevated antioxidant activity. Sensorial analyses ranked the cultivar with high soluble solids concentration:titratable acidity (SSC:TA) and reduced firmness the highest overall. Red flesh is a highly desirable trait for breeding programs aiming to improve consumption of peaches selected for nutraceutical properties.
Phenolic compounds in fruit provide human health benefits, and they contribute to color, taste, and the preservation of post-harvest fruit quality. Phenolic compounds also serve as modifiers of ...enzymatic activity, whether inhibition or stimulation. Polyphenol oxidases (PPO) and peroxidases (POD) use phenolic compounds as substrates in oxidative browning. Apple browning leads to flesh color, taste, texture, and flavor degradation, representing a drawback for the variety and its' market appraisal. This study was conducted to investigate the process of browning in 14 apple cultivars throughout post-harvest at three-time points: immediately (T0), one hour (T1), and 24 h (T2) after apples were cut in half. Color parameters L* (lightness), a* (red/green), b* (yellow/blue) were measured, and chroma (Δ
*) and color (ΔE) were calculated to quantify differences between T0₋T1 and T1₋T2 on the fruit surface. Enzymatic activity (PPO, POD) and phenolic composition were also quantified for each cultivar. 'Granny Smith' and 'Cripps Pink' browned minimally. In contrast, 'Fiesta' and 'Mondial Gala' browned severely, reporting high enzymatic activity and quantified phenolic concentration (QPC). Phenolic compound polymerization appears to play a significant role in enzymatic inhibition. 'Topaz' does not fit the high QPC, PPO, and browning formula, suggesting alternative pathways that contribute to apple browning.
‘WA 38’ (‘Enterprise’ × ‘Honeycrisp’) is an apple variety that is characterized by a peculiar self-thinning trait in which most of the fruitlets naturally shed within the first 8 weeks after bloom, ...leaving some clusters empty, but most with 1–2 apples. This study aimed to investigate potential causes for the relatively low fruit set observed in ‘WA 38’ by investigating its flower biology. This study comprised three objectives: (1) To characterize the effective pollination period (EPP) of ‘WA 38’ by studying stigmatic receptivity, pollen tube growth, and ovule longevity in ‘WA 38’ flowers, (2) to compare the pollen tube growth of 5 fully compatible pollinizer varieties in ‘WA 38’ pistils, and (3) to evaluate fruit and seed set resulting from controlled pollinations with 5 fully compatible pollinizer varieties. The results showed ‘WA 38’ EPP was approximately 3.2 days in 2019 and 1.4 days in 2020, and that differences in pollen sources did not attribute significant differences in fertility in ‘WA 38’ flowers. The results of this study suggest mechanisms other than pollination and fertilization, such as competition among fruitlets within a cluster or hormone signaling, may have a stronger impact on ‘WA 38’ fruitlet abscission.
Fruit development, maturation and ripening consists of a complex series of biochemical and physiological changes that in climacteric fruits, including apple and tomato, are coordinated by the gaseous ...hormone ethylene. These changes lead to final fruit quality and understanding of the functional machinery underlying these processes is of both biological and practical importance. To date many reports have been made on the analysis of gene expression in apple. In this study we focused our investigation on the role of ethylene during apple maturation, specifically comparing transcriptomics of normal ripening with changes resulting from application of the hormone receptor competitor 1-methylcyclopropene.
To gain insight into the molecular process regulating ripening in apple, and to compare to tomato (model species for ripening studies), we utilized both homologous and heterologous (tomato) microarray to profile transcriptome dynamics of genes involved in fruit development and ripening, emphasizing those which are ethylene regulated.The use of both types of microarrays facilitated transcriptome comparison between apple and tomato (for the later using data previously published and available at the TED: tomato expression database) and highlighted genes conserved during ripening of both species, which in turn represent a foundation for further comparative genomic studies. The cross-species analysis had the secondary aim of examining the efficiency of heterologous (specifically tomato) microarray hybridization for candidate gene identification as related to the ripening process. The resulting transcriptomics data revealed coordinated gene expression during fruit ripening of a subset of ripening-related and ethylene responsive genes, further facilitating the analysis of ethylene response during fruit maturation and ripening.
Our combined strategy based on microarray hybridization enabled transcriptome characterization during normal climacteric apple ripening, as well as definition of ethylene-dependent transcriptome changes. Comparison with tomato fruit maturation and ethylene responsive transcriptome activity facilitated identification of putative conserved orthologous ripening-related genes, which serve as an initial set of candidates for assessing conservation of gene activity across genomes of fruit bearing plant species.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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