Implications For Fruit Quality Research Articles

Dynamics of the Apple Fruit Microbiome after Harvest and Implications for Fruit Quality.

The contribution of the apple microbiome to the production chain of apple was so far largely unknown. Here, we describe the apple fruit microbiome and influences on its composition by parameters such as storage season, storage duration, storage technology, apple variety, and plant protection schemes. A combined culturing and metabarcoding approach revealed significant differences in the abundance, composition, and diversity of the apple fruit microbiome. We showed that relatively few genera contribute a large portion of the microbiome on fruit and that the fruit microbiome changes during the storage season depending on the storage conditions. In addition, we show that the plant protection regime has an influence on the diversity of the fruit microbiome and on the dynamics of pathogenic fungal genera during the storage season. For the genus Neofabraea, the quantitative results from the metabarcoding approach were validated with real-time PCR. In conclusion, we identified key parameters determining the composition and temporal changes of the apple fruit microbiome, and the main abiotic driving factors of microbiome diversity on apple fruit were characterized.

Acidity Drop and Coloration in Clementine: Implications for Fruit Quality and Harvesting Practices.

The commercial quality of fruit is the result of a combination of internal (acidity, sugars, juice, etc.) and external characteristics (shape, size, color, visual defects, etc.). On citrus, the internal maturity of fruit is often reached prior and independently to their external maturity, inducing the use of degreening practices to artificially color fruit. However, for some sectors where degreening is not authorized, such as organic farming or up-market, it is important to understand the co-occurrence between fruit coloration and internal ripening, and its impact on fruit quality and harvesting management. Our study was based on a monitoring of the color and acidity of Protected Geographical Indication “Clémentine de Corse” orchards of producers in 2013 and 2014. Our results show that: (i) the dynamics of acidity drop during maturation are similar from one plot to another but staggered in time; (ii) fruit coloring occurs at different times during acidity drop; (iii) the synchronization between the coloring process and acidity drop determines both the quality of harvested fruit and the period during which orchards are harvestable, which we called the “harvestability window.” This study sheds new light on the quality of citrus harvested without fruit degreening and leads to propose actions to anticipate internal maturity evolution according to the coloring and spreading of the harvest period. The fruit acidity model obtained in this study will be extended to a practical application tool to predict fruit acidity and quality for a better-controlled harvest management.

Measurement and evaluation of the effect of vibration on fruits in transit—Review

Mechanical vibration is a prominent cause of produce damage in many postharvest fruit supply chains. Knowledge on the causes, occurrence, and mechanistic relationship of vibration to produce damage is important for systematic development of remedial actions. This review identifies and discusses the critical factors of vibration, their implications for fruit quality, and possible improvements to addressing the issue of fruit quality deterioration. Frequently reported mechanical damage types caused by vibration on fruits are scuffing, fruit rub, and skin bruising. A wide range of factors can significantly affect the vibration intensity and thus resultant mechanical damage. Critical frequencies of vibration in the range of 0 to 10 Hz, attributed to peak energy levels in the power spectrum, cause substantial damage in fruits. Greater vertical acceleration and transmission of vibration to the higher tiers in a stacked column of packages result in increased mechanical damage. Fruit packages stacked in the rear positions of trucks are also affected more by vibration. Produce transported in leaf spring trucks has a higher risk of damage when compared with air‐ride suspension trucks. Additionally increased road roughness, vehicle speed, and duration of exposure to vibration proliferate fruit damage. The effects of different inner packing methods and different package types on mechanical damage are less frequently investigated. More accurate characterization of mechanical damage caused by vibration and shocks and its reproduction by enhanced simulation methods will contribute to optimizing damage prevention mechanisms and further improving the quality of fruits in transit within the postharvest supply chain.

Watermelon and melon fruit quality: The genotypic and agro-environmental factors implicated

Abstract Watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] and melon (Cucumis melo L.) are popular annual fruit crops of the gourd family Cucurbitaceae, drawing from discrete botanical backgrounds. For both these dessert fruits, quality is what mainly influences consumer behavior and formulates recurring purchasing habits and brand loyalty within reasonable cost. The current review examines the configuration of sensorial quality attributes during development and ripening, as compounded by highly coordinated growth and differentiation processes of various fruit tissues associated with differential expression of stage-specific genes, which affect flavor, aroma, color and texture. The genotypic effect on fruit quality is examined, which in the case of sweet melon is ramified into varietal groups demonstrating differential ripening physiology of climacteric or non-climacteric nature with important implications for key sensorial characteristics, especially aroma and texture. Current advances on the role of key agronomic factors influential on quality are discussed, such as grafting and rootstock-scion interaction, controlled water and thermal stress, targeted plant nutrition applications, and the genotype × environment × management interaction. Several cardinal issues warranting further research were identified: the ripening-dependent accumulation and metabolism of carotenoids and the link between carotenoid profiles and volatile fractions, particularly the role of apocarotenoids as substrates in the synthesis of aroma volatile molecules; the coexistence of ethylene-dependent and ethylene-independent regulation of ripening processes in melons; physiological incompatibility in melon graft combinations and its implications for fruit quality; rootstock mediation of watermelon volatile fraction; the role of osmoregulatory molecules as l -citrulline in cell expansion and turgor affecting mesocarp firmness; stage-specific carbohydrate partitioning and metabolism in developing fruit and its potential manipulation through thermal treatments; robust model building on transplanting dates, resilient to genotype × environment interaction. Understanding the concerted effects of the genotypic, physiological and agro-environmental factors visited in the current review is instrumental in the efforts for improving quality and expanding market share for watermelon and melon fruit.

Fruit thinning in ‘Conference’ pear grown under deficit irrigation: Implications for fruit quality at harvest and after cold storage

Fruit thinning in pear is feasible for mitigation of water stress effects. However, it is not well known how fruit quality at harvest and after cold storage is affected by pre-harvest water stress. Even less is known about the effects of fruit thinning on quality under these circumstances. To elucidate these, we applied deficit irrigation (DI) and fruit thinning treatments to ‘Conference’ pear over the growing seasons of 2008 and 2009. At the onset of Stage II (80 and 67 days before harvest in 2008 and 2009, respectively), two irrigation treatments were applied: full irrigation (FI) and DI. FI trees received 100% of crop evapotranspiration (ETc). DI trees received no irrigation during the first three weeks of Stage II to induce water stress, but then received 20% of ETc to ensure tree survival. From bud-break until the onset of Stage II and during post-harvest, FI and DI trees received 100% of ETc. Each irrigation treatment received two thinning levels: no thinning leaving commercial crop load (∼180 fruits tree −1), and hand-thinning at the onset of Stage II leaving a light crop load (∼85 fruits tree −1). Under commercial crop loads, DI trees were moderately water-stressed and this had some positive effects on fruit quality. DI increased fruit firmness (FF), soluble solids concentrations (SSC) and acidity at harvest while no changes were observed in fruit maturity (based on ethylene production). Differences in FF and acidity at harvest between FI and DI fruit were maintained during cold storage. DI also reduced fruit weight loss during storage. But fruit size was reduced under DI. Fruit thinning under DI resulted in better fruit composition with no detrimental effect on fresh-market yield compared to un-thinned fruit. Fruit size at harvest and SSC values after five months of cold storage were higher in fruit from thinned trees than fruit from un-thinned trees. Fruit thinning increased fruit ethylene production, indicating advanced maturity. This may lead to earlier harvest which is desirable in years with impending drought. Fruit thinning is therefore a useful technique to enhance pear marketability under water shortage.

Vineyard variability in Marlborough, New Zealand: characterising spatial and temporal changes in fruit composition and juice quality in the vineyard

Background and Aims: Previous work has demonstrated that vineyards are spatially variable and that this variability can be understood in terms of the underlying characteristics of the land (soils, topography) supporting the vineyard. Selectively harvesting blocks in response to such variability may be highly profitable. While it has also been shown that crop maturation is spatially variable, there may also be temporal variations in the rate of maturation. Integrating knowledge of how spatial variation in fruit composition may be moderated in time has not previously been attempted and is the key objective in this work. Methods and Results: We used a proximal sensor to map vine vigour at high spatial resolution in a 5.9-ha Marlborough vineyard planted with Sauvignon Blanc. Vigour measurements were also related to fruit-soluble solids (SS), titratable acidity (TA) and pH – key indices of crop maturity. Knowledge of crop phenology and maturation was used to predict how these indices changed with time. The pooled opinions of over 50 Marlborough winemakers on the optimum juice SS, pH and TA at harvest to produce a ‘typical Marlborough Sauvignon Blanc’ were used to develop a juice index (JI), which in turn was mapped in space and time at the study site. The JI showed marked spatial and temporal variation. Conclusions: In addition to being spatially variable, grape quality in vineyards also changed with time. Thus, the optimisation of decisions about harvest timing requires knowledge of spatial variability. Conversely, strategies such as selective harvesting cannot be properly optimized without knowledge of crop phenology, the maturation of fruit and their implications for fruit quality – which are all also spatially variable. In this study, we have shown that, by integrating knowledge of crop phenology with an understanding of vineyard variability and winemaker objectives through the construction of a JI, it is possible for the optimum harvest decision to be made such that fruit destined for a particular end use are harvested at the right time and from the right place. Significance of the Study: This is the first study in which knowledge of both spatial and temporal vineyard variation has been integrated. It demonstrates that in order to be optimal, strategies such as selective harvesting need to incorporate knowledge of crop phenology rather than rely on knowledge of spatial variation alone.

Mitigation of severe water stress by fruit thinning in ‘O’Henry’ peach: Implications for fruit quality

Fruit thinning can be used to relieve water stress in peach but it is not known how fruit quality will respond under water limited conditions. To elucidate this, we applied, over the growing seasons of 2003 and 2004, irrigation and fruit thinning treatments to ‘O’Henry’ peach at the onset of Stage III of fruit development. The treatments were full irrigation (FI) and no irrigation (NI) with each receiving three crop load levels: light, commercial and heavy. Fruit size and fruit skin colouration were lower in NI than in FI but the following were higher in NI fruit: firmness, juice titratable acidity and electrical conductivity, and concentrations of dry matter and soluble solids. All the quality parameters were significantly correlated with tree water status, expressed as midday stem water potential. NI fruit matured 5–10 days later than FI fruit. The increased dry matter concentration, juice acidity, and electrical conductivity in NI fruit were indicative of lower quality at harvest. Choosing a light crop load was not effective in improving NI fruit quality except for the size. Since fruit size is the most important fruit quality attribute, its increase might compensate for yield losses resulting from heavy fruit thinning. Nevertheless, when heavy thinning is performed for mitigation of water stress in Stage III, the overall fruit quality will suffer if severe water stress is inevitable because of shortage or lack of irrigation water.

Modelling apple orchard systems

While a number of models have been developed to assist managers of deciduous fruit tree crops with specific aspects of decision making, most are non-optimising predictive models and few employ detailed mechanistic models of fruit-tree growth that would enable the simulation of any orchard system from planting to maturity. This paper details the complex biological and economic relationships present in an apple orchard system and describes a dynamic simulation model based on these interactions. The model is bioeconomic in nature, and may be used to investigate a range of issues of relevance to the commercial apple orchardist. These issues include understanding how biological factors influence apple-tree productivity, and how to choose among a diverse range of apple orchard systems. Each system, consisting of a particular combination of cultivar, rootstock, tree spacing and training method, has implications for fruit quality, quantity and ultimately profit. The choice of system is made at planting, while an important annual decision is the optimal rate of thinning, both of which determine potential yield over the lifetime of the orchard. These decisions also influence costs and revenues per hectare and, by necessity, are made in the context of unknown future prices of inputs and outputs. The bioeconomic model is used to maximise net present value of one orchard system by selecting optimal thinning strategies over a 15-year period.

Postpollination Nectar Reabsorption and Its Implications for Fruit Quality in an Epiphytic Orchid1

ABSTRACTWe present evidence that pollination triggers nectar reabsorption in flowers of the epiphytic orchid Mystacidium venosum. The amount of sugar in nectar of M. venosum decreased significantly by more than 50 percent within 72 hours of pollination. Hand–pollinated flowers from which nectar was previously removed set significantly smaller fruits with a lower percentage of viable seeds than hand–pollinated flowers containing nectar, suggesting that resources reclaimed by nectar resorption are allocated to fruit production.

Postpollination Nectar Reabsorption and Its Implications for Fruit Quality in an Epiphytic Orchid1

Abstract We present evidence that pollination triggers nectar reabsorption in flowers of the epiphytic orchid Mystacidium venosum. The amount of sugar in nectar of M. venosum decreased significantly by more than 50 percent within 72 hours of pollination. Hand-pollinated flowers from which nectar was previously removed set significantly smaller fruits with a lower percentage of viable seeds than hand-pollinated flowers containing nectar, suggesting that resources reclaimed by nectar resorption are allocated to fruit production.