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Fresh-cut ‘Braeburn’ apple slices were dipped into cold water (4 °C for 2 min) or hot water (HWT, 48 °C or 55 °C for 2 min) followed by dips into 0 or 6% w/v aqueous calcium ascorbate (CaAsc, 2 min, 0 °C) and stored in air up to 28 d at 4 °C. Microbial counts, changes in browning and sensory acceptance were determined to indicate changes in quality. Changes in antioxidant levels were measured using free radical scavenging activity (DPPH), reducing activity (FRAP), ascorbic acid content (AA) and polyphenolic content (by HPLC). CaAsc dips had a strong impact reducing the browning through increasing the flesh luminosity and hue angle. 6% CaAsc in fresh-cut apples extended the overall acceptability from less than 7 d to 14 d. Immediately after CaAsc treatment, AA content was 5 fold higher (0.25–1.25 g kg−1) than those not dipped into CaAsc. However, the combination of HWT treatments and CaAsc dips led to seven fold increased levels of AA inside the apple tissue (0.25–1.85 g kg−1) and consequently increased the antioxidant activity. HWT did not increase the AA content when not combined with CaAsc dips. The HWT CaAsc dip extended the overall acceptability to 21 d compared to 14 d for samples not heated but dipped into CaAsc. Shelf life was ultimately limited by sensory quality. At day 28, total plate counts were reduced from 5.3 log cfu/g (untreated slices) to 4.6 log cfu/g in the 6% CaAsc dips and further to 3.9 log cfu/g with the combination of HWT and CaAsc dip. Changes in the content of phenolic compounds with time, HWT and CaAsc dip were generally not significant except for slightly increased quercetin and phloridzin levels and decreased p-coumaric and procyanidins over time. The combination of HWT at 48 °C for 2 min followed by 6% CaAsc dip would be best for preserving the eating quality of apple slices.

This study was set up to identify critical maturity indices affecting storage potential of apricots and demonstrate the potential for using non-destructive measurements to segregate harvested crops for sequential marketing. Fruit of two apricot ( Prunus armeniaca ) cultivars (‘Clutha Gold’ and ‘Genevieve’) were harvested and stored for four weeks at 0 °C followed by four days of simulated shelf life at 20 °C. Fruit colour, acoustic firmness, impact firmness, flesh firmness (FF 0 ), dry matter content and soluble solids content measured non-destructively at harvest were correlated to the flesh firmness measured at the end of refrigerated storage and simulated shelf life (FF Final ) through stepwise regression. The regression models indicated that FF 0 is a predominant factor determining FF Final . According to the exponential model describing the relationship between FF 0 and FF Final , ‘Genevieve’ and ‘Clutha Gold’ could be stored at 0 °C for four weeks if harvested at firmness above 47 or 56 N, respectively. Segregation of harvested crops according to FF 0 estimated from VNIR would enable sequential marketing of fruit according to storage potential to reduce fruit loss.

In order to develop practical sea freight and marketing options for high quality red capsicums, we have investigated washing treatments that can minimize deterioration when fruit are subsequently stored under high humidity packaging conditions, at cool (6–8 °C) and warm (20 °C) temperatures. In small-scale trials using vented plastic bags to provide high humidity, fruit washed with unheated high-pressure water (517 kPa) had reduced incidence of flesh rots and deterioration of the calyx and stem compared to controls (unwashed or passed through a commercial packing line) or hot water drenched fruit (55 °C for 30 s) following a high humidity storage regime of 2 weeks at 6–8 °C and a further 14 d at 20 °C. In a more extensive trial where 5 kg boxes of fruit were used as replicates, washing with high-pressure water, packing in unperforated plastic box-liners and storing at 6–8 °C for 2 weeks, then 21 d at 20 °C resulted in 84% acceptability. In contrast, acceptability of fruit treated in a commercial packing line stored under regular (uncontrolled humidity) conditions or inside box liners (high relative humidity) declined rapidly at 20 °C after 2 weeks cool storage, with final acceptabilities of 10% and 39% after 21 d, respectively. We conclude that high-pressure water washing is an effective cleaning step, permitting high humidity to be used to prevent shrivel during cool-storage and subsequent ambient conditions, while minimizing the incidence of flesh rots or calyx/stem deterioration. Extended capsicum quality in high humidity at room temperature suggests that (a) cool-storage during transport to some markets may not be necessary if fruit are cleaned to a high standard and (b) fruit could remain within a box liner right up until the product is displayed on the supermarket shelves.

Metabolic stress disinfection and disinfestation (MSDD) is a potential quarantine treatment in which a combination of cycles of rapid decompression and compression are followed by exposure to ethanol vapour under decompression. The response of ‘Hass’ avocado ( Persea americana Mill., cv. Hass) to MSDD treatment for control of longtailed mealybug ( Pseudococcus longispinus ) was investigated. The best treatment for the most resistant life stage (2nd/3rd instars) was 90-min MSDD treatment with 371 mg L −1 ethanol. Early and late season ‘Hass’ avocados were subjected to MSDD treatments (with 371 mg L −1 ethanol), or in air (control). Following the treatments, early season fruit were ripened at 20 °C and 25 °C. Half of the late season fruit were ripened at either 20 °C or 25 °C, and the remainder were stored at 5.5 °C for 6 weeks, then ripened at 20 °C. There were no significant difference in quality and rot incidence between non-treated controls and MSDD-treated fruit. The main disorders found were stem-end and body rots, vascular browning and flesh greying for the stored fruit. There were also no significant differences in fruit respiration rate or ethylene production. Thus, MSDD was shown to be a potentially ‘soft’ disinfestation treatment for surface pests of avocado.

The vase life of Asiatic lilies can be limited by leaf yellowing, which can be caused by exposure to low light or temperature during winter growth or in storage. We examined the use of postharvest hot water treatments (HWTs) as a means of reducing leaf senescence in stored (4 °C for 2 weeks) and non-stored Asiatic hybrid lily ‘Elite’ ( Lilium sp.). A range of HWTs (45–55 °C for 2.5 or 5 min) was applied to leaves on cut lily stems (but not flowers). Higher temperatures and the longer duration resulted in heat damage, but treatments of 50 °C for 5 min and 52.5 °C for 2.5 min were found to be optimal for minimising leaf yellowing with trace levels of heat damage for both non-stored and stored stems. The onset of yellowing was delayed by 3–4 d, and the occurrence of an unacceptable level of yellowing eliminated for up to 12 d (compared with F v / F o ) over time, which was more marked in lower than upper leaves (thus correlating with yellowing, which was more severe in the lower leaves). Although both optimal HWTs resulted in an initial reduction in yield, there was a recovery over time resulting in a yield that, by 12 d, was as high or significantly higher than control leaves (particularly for the lower leaves). All treatments showed a reduction in chlorophyll content (total, chlorophyll a and chlorophyll b ), but control leaves had significantly lower levels after 7 d. HWTs show potential as a non-chemical, simple means of delaying leaf yellowing of Asiatic lilies and thus increasing vase life.

Metabolic stress disinfection and disinfestation (MSDD) is a relatively new quarantine treatment in which fruit are exposed to rapid decompression and compression cycles and high CO 2 atmosphere, followed by exposure to ethanol vapour under decompression. This study evaluated the ripening response of ‘Hayward’ kiwifruit ( Actinidia deliciosa ) and ‘Pink Lady’ apple ( Malus x domestica ) to MSDD treatment, which can control longtailed mealybug ( Pseudococcus longispinus ). Following the treatments, fruit were held at 20 °C for 7 d for shelf-life assessment, while the remainder were refrigerated at 0.5 °C for 16 weeks. Respiration rate, volatile (ethylene, ethanol and acetaldehyde) production rates, firmness and disorders were measured at regular time intervals. MSDD treatments did not affect the metabolic activities and quality of ‘Pink Lady’ apples. However, firmness was reduced by 4.9 N in non-refrigerated MSDD treated fruit. MSDD treatments did not control superficial scald disorder in refrigerated ‘Pink Lady’ apples. For ‘Hayward’ kiwifruit, treatments increased the respiration rate and ethylene production of short-term refrigerated fruit, promoted endogenous production of ethanol and acetaldehyde in both short-term and long-term refrigerated fruit. MSDD treatments also increased the incidence of rots in refrigerated ‘Hayward’ kiwifruit. MSDD treatments accelerated the softening of short-term refrigerated kiwifruit, but retarded the softening of ‘Hayward’ kiwifruit during the 16 weeks of refrigerated storage. MSDD could potentially be used as a quarantine treatment of apples. Further studies are required on the sensory effect of MSDD treatment.

In the export of ‘Fuyu’ persimmon, fruit are airfreighted at ambient temperatures, or seafreighted at low temperatures using modified atmosphere (MA) packaging. Since persimmons are climacteric and ethylene sensitive, exposure to exogenous ethylene may accelerate natural softening at ambient temperature (e.g. airfreight) as well as aggravate chilling injury during coolstorage (e.g. seafreight). In the present work, the response of this cultivar to exogenous ethylene exposure was studied in four critical handling scenarios that might occur in a commercial chain. Non-packed fruit exposed to ethylene and then held at 20 °C (simulated airfreight) showed the greatest sensitivity to ethylene; fruit firmness and colour during shelf life were affected by even 1 d of exposure to 0.2 μL L−1 ethylene. Lower sensitivity was observed when fruit were stored at 0 °C under MA conditions after ethylene exposure at 20 °C (simulated pre-packing exposure-seafreight), where fruit quality was not affected by exposures of 1 d at ≤1 μL L−1, and only slightly by 2 d at

Insights into the relative importance of various aspects of product quality can be provided through quantitative analysis of consumer preference and choice of fruit. In this study, methods previously used to establish taste preferences for kiwifruit (Harker et al., 2008) and conjoint approaches were used to determine the influence of three key aspects of avocado quality on consumer liking and willingness to purchase fruit: dry matter percentage (DM), level of ripeness (firmness) and internal defects (bruising). One hundred and seven consumers tasted avocados with a range of DM levels from ~20% (minimally mature) to nearly 40% (very mature), and at a range of fruit firmness (ripeness) stages (firm-ripe to soft-ripe). Responses to bruising, a common quality defect in fruit obtained from the retail shelf, were examined using a conjoint approach in which consumers were presented with photographs showing fruit affected by damage of varying severity. In terms of DM, consumers showed a progressive increase in liking and intent to buy avocados as the DM increased. In terms of ripeness, liking and purchase intent was higher in avocados that had softened to a firmness of 6.5 N or below (hand-rating 5). For internal defects, conjoint analysis revealed that price, level of bruising and incidence of bruising all significantly lowered consumers' future purchase decision, but the latter two factors had a greater impact than price. These results indicate the usefulness of the methodology, and also provide realistic targets for Hass avocado quality on the retail shelf.

Fresh-cut ‘Braeburn’ apple slices were dipped in calcium ascorbate (CaAsc; 0, 2, 6, 12 and 20%, w/w) and stored in air or under modified atmosphere (MA) conditions for up to 28 d at 4 °C. Changes in antioxidant levels were measured using free radical scavenging activity (DPPH), reducing activity (FRAP), ascorbic acid content (AA) and polyphenolic content (by HPLC). Changes in browning, sensory quality and microbial counts were measured to indicate eating quality. CaAsc dips increased the initial levels of AA from 0.19 g kg−1 in the untreated control to 3.8 g kg−1 for the 20% CaAsc treatment. Ascorbic acid content of treated slices during storage decreased by more than 50% in CaAsc concentrations of 6, 12 and 20%. Similar patterns were observed for FRAP and DPPH activities. Untreated or 2% CaAsc treated slices stored in air or MA showed browning, microbial deterioration and poor sensory quality, thus resulting in a short shelf life (

Susceptibility of ‘satsuma’ mandarin fruit (Citrus unshiu Marc) to chilling injury limits the marketability of stored fruit. In this study, the effect of hot water dip (HWD) treatments on chilling injury tolerance, fruit quality, activity of antioxidant enzymes, and gene expression of proton transporters in the vacuole were investigated in New Zealand. Some treatments suppressed chilling injury development, but none of them could prevent it completely. The major reduction in chilling injury incidence (proportion of unacceptable fruit) and severity (level of damage) was observed in HWD at 50 °C, for 2 min. Temperatures higher than 50 °C increased fruit peel damage. Chilling injury was paralleled by higher ethylene production and respiration rate in affected fruit, and an increase in the amount of ethanol and acetaldehyde emitted in juice headspace. Afterwards, values decreased gradually with increasing chilling damage. Treatments that reduced chilling injury suppressed anaerobic products, ethylene evolution and respiration. During storage at 2 °C for 8 weeks, a decline in catalase (CAT) activity was observed, while peroxidase (POX) activity increased. This rapid increase in POX activity was associated with increased peel damage due to both chilling injury and heat damage. Decreasing chilling injury in HWD was correlated with decreased POX activity and maintenance of CAT activity during storage. Amounts of vacuolar pyrophosphatase (V-PPase) and vacuolar ATPase (V-ATPase) gene transcript in fruit peel were reduced by heat treatment. Storage periods reduced V-PPase and induced V-ATPase gene transcript level in fruit treated at 50 °C, but this was not associated with changes in the acid content in the juice. A significant induction (5–6-fold) of ATPase and V-PPase occurred in juice sacs and this may be associated with compensation for a loss of tonoplast integrity in fruit treated at 55 °C compared to those at 50 °C. We also found that V-ATPase and V-PPase transcript levels in juice sacs responded rapidly to heat treatments but were largely recovered after 8 weeks cold storage for successful (non-damaging) heat treatments. The optimal HWD treatments were 47.5–50 °C for 2 min.

The dry matter (DM) content in the flesh of harvested avocado is quite variable, ranging from low DM ( 35%) fruit that are potentially suitable for processing. Currently, no suitable method exists for segregating these categories in harvested lines. Compositional analysis of the skin, seed and flesh of 1000 mature ‘Hass’ avocado ( Persea americana Mill.) fruit was undertaken to determine the feasibility of employing a density technique to identify such fruit on the basis of their flesh DM. Measurements included whole-fruit density, and the mass, density and DM of both core plugs of individual tissues from unripe fruit, and the separated tissues of each fruit upon ripening. The proposition was evaluated by extending basic density theory to develop a generic multi-term expression for a whole-fruit system where the density of each component (the skin, seed and flesh) was characterized with regard to its water, DM and air content. At harvest whole-fruit densities ranged between 970 and 1018 kg m −3 , and flesh DMs between 23 and 43%, with a correlation of r = −0.29; P

Dragon fruit ( Hylocereus undatus ) are a host of fruit fly ( Bactrocera spp.), and thus export to many markets will require a disinfestation treatment. This work investigated the potential for disinfestation by heat treatment (HT) of cv. Binh Thuan in order to meet the biosecurity requirements of importing countries. Main-season fruit from Viet Nam were subjected to hot air treatments and stored for 2–4 weeks storage at 5 °C in sealed polypropylene bags, and fruit quality examined during subsequent shelf-life at 20 °C. HTs applied were fruit core temperatures (FCT) of 46.5 °C for durations of 20 and 40 min, and 48.5 °C for 50, 70 and 90 min. Assessments included turgor of the bracts and stem, the appearance of the body of the fruit and presence of rots, skin colour, flesh firmness, soluble solids concentration, fruit acidity, taste, and flesh translucence. ‘Binh Thuan’ Dragon fruit proved to be tolerant of hot air treatment and at the lower HT temperature (FCT 46.5 °C for 20 min) fruit quality was not significantly different from non-heated control fruit, either after treatment at harvest, or after storage for up to 4 weeks. However, metrics quantifying the appearance of both control- and HT-fruit generally deteriorated with storage time at 5 °C, although the internal appearance of the flesh, and taste, remained acceptable throughout. Shelf-life effects were restricted to comparison of the lower HT temperature (FCT 46.5 °C for 20 min) and non-heated control fruit. Shelf-life after any of the storage periods was terminated after only 4 d, as fruit available for study had not been sprayed with fungicides during the season, and developed anthracnose rots readily at 20 °C. No differences in shelf-life characteristics were established between HT fruit and control fruit. Our results provide strong evidence that ‘Binh Thuan’ Dragon fruit are a suitable candidate for fruit fly disinfestation by hot air HTs, and that fruit quality during or after storage does not suffer as a consequence.

Physiological disorders occur when ‘Hass’ avocados are stored for more than approximately 4–6 weeks. The major disorder is diffuse flesh discolouration (“flesh greying”, or “internal chilling injury”), but others include vascular browning, vascular leaching (browning of flesh around the vascular bundles), stringy vascular tissue (thickening and separation of the vascular strands), and outer flesh blackening (blackening of the outmost layer of the mesocarp). We have examined 1-MCP effects on ‘Hass’ avocados stored for 4 or 7 weeks at 5.5 ◦ C following treatment with 50–1000 nl l −1 1-MCP for 6–24 h, at 6 or 15 ◦ C. The effect of harvest date (fruit maturity) on responsiveness to 100 and 500 nl l −1 1-MCP was examined. 1-MCP treated fruit were firmer following storage, had reduced skin colouration (purpling) at removal from storage (4 or 7 weeks), increased time to softening, and reduced physiological disorders associated with long-term storage. Relatively little difference was observed between fruit treated at 15 and 6 ◦ C, and thus a treatment temperature of 6 ◦ C was used in the remaining experiments. For lower 1-MCP concentrations, short treatment durations influenced time to ripen, but not fruit quality. Treatment times of 12 and 24 h produced similar results. Harvest date (fruit maturity) influenced the levels of disorders in non-1-MCP treated fruit, but had little overall effect on 1-MCP efficacy. 1-MCP treatment was of little benefit for fruit stored for 4 weeks but, particularly if the 1-MCP concentration was high (250 nl l −1 ), excessively delayed the time to ripen. After 7 weeks storage 100 nl l −1 1-MCP almost completely eliminated some long-term storage disorders. A small trial showed that 500 nl l −1 1-MCP did not reduce external chilling injury (skin blackening) of ‘Hass’ avocados induced by 0 ◦ C storage. Overall, 1-MCP shows promise as a tool

Pretreatments at moderate temperatures applied immediately prior to the high or low temperature treatments can reduce skin damage to avocados. These temperature tolerance-inducing pretreatments have generally been applied immediately prior to the high or low temperature. We examined whether a delay between the pretreatment and potentially damaging high and low temperatures may cause a loss in the induced tolerance. A hot air pretreatment (38 °C for 6 h) applied prior to storage at 0 °C for 3 weeks with intervening delays of 1–4 days at 20 °C, showed a large reduction in chilling injury as a result of the pretreatment but that this was progressively lost with increasing delay to storage. Hot water pretreatments (38 °C for 0, 5, 20 and 60 min) increasingly reduced chilling damage at 0 °C, and heat damage from a hot water treatment (HWT) at 50 °C/10 min. With delays of up to 3–24 h prior to the HWT, heat damage was reduced for the 5 and 20 min pretreatments. However, delays up to 5 days between pretreatment and HWT, loss of heat tolerance was observed. For delays of between 1 and 5 days there was a clear loss of chilling tolerance which was more rapid than the increase in chilling injury in control treatments for the same delays. However, the effect of delays

Skin of 'Hass' avocados (Persea americana Mill.) changes colour from green to purple/black as fruit ripen. This colour change is important as an indicator of ripeness for both industry and consumers. We sought to characterise pigment changes during ripening of 'Hass' avocados. Skin colour and changes in chlorophyll and anthocyanin concentrations in relation to fruit firmness at three ripening temperatures (15, 20 and 25 °C) were studied. As fruit ripened, skin colour changed from green, to purple, to black, which was observed as a decrease in L, chroma and hue. Total anthocyanins in skin tissue increased during ripening, but this increase was due almost entirely to a single anthocyanin; cyanidin 3-O-glucoside. Cyanidin 3-O-glucoside concentration increased after 3-6 days postharvest (depending on ripening temperature), and levels increased earlier, and were higher, with higher ripening temperature. Chlorophyll a and b levels decreased until 4-5 days after harvest, but did not change significantly thereafter. No significant differences in chlorophyll concentration were observed among the three ripening temperatures. Fruit harvested directly from the tree (unripe) with skin darkening showed similar pigments changes to that during ripening (reduced chlorophyll and increased cyanidin 3-O-glucoside). Colour change in 'Hass' avocados from green to purple, then black, results from an initial decrease in chlorophyll content, followed by an increase in the levels of the anthocyanin, cyanidin 3-O-glucoside.

‘Hass’ avocado harvested at four different times during a growing season, was analysed by both reflectance and interactance NIR spectroscopy to establish its reliability for the non-destructive determination of fruit dry matter (DM). Mean DM increased from 27.7 to 36.8% during the course of the study. Relationships between spectral wavelengths and DM were evaluated by application of chemometric techniques to partial least squares (PLS) and multiple linear regression (MLR) models, using calibration and validation statistics of predictions to compare their efficacy. The interactance mode was a superior predictor of fruit DM compared with reflectance. A PLS model applied to interactance data from fruit from all harvests combined (n=239) gave a goodness-of-fit (Rp2) between predicted and actual DM measurements of 0.88, and an error of prediction (RMSEP) of 1.8% DM. MLR models incorporating four wavelengths returned equivalent validation statistics. Three of these wavelengths, in the vicinity of 900–920 nm, are consistent with the CH absorbance band, leaving only a minor role for water-related absorbances. These observations suggest on-line commercial NIR systems capable of operating in an interactance mode have the potential to usefully grade avocado on the basis of their DM content, to improve taste and oil content.

Storage of avocado fruit is limited by the development of skin damage (external chilling injury) when fruit are stored at temperatures of less than about 3 °C. The potential for low temperature conditioning to reduce external damage of ‘Hass’ avocados was examined. Avocados harvested in early summer were conditioned at temperatures of 4, 6, 8, 10, 12 and 15 °C for a period of 0, 1, 2, 3, 4 or 5 days before 3 weeks storage at 0 °C. Three days after removal from coolstore, external damage was rated, and internal quality assessed after ripening at 15 °C. The experiment was repeated in late summer, but fruit were stored for 4 weeks at 0 °C, and only external damage was measured. Control fruit stored at 0 °C for either 3 or 4 weeks exhibited severe external damage, manifested as blackening and pitting over almost the whole fruit surface. Conditioning temperatures of 4–10 °C reduced skin damage. The optimum temperature/time combinations were 6 or 8 °C for 3–5 days prior to 0 °C storage. Ripe-fruit quality was also highest in these treatments. Weight loss, ethylene and CO2 production were not associated with the reduction in external damage, and the response observed is therefore likely to be due to a low temperature, rather than a ripening response.

The potential for hot water treatment (HWT) to improve quality of ‘Hass’ avocado following cold disinfestation for fruit flies, was investigated. Avocado fruit were placed in water at 38–42 °C for 20–60 min, disinfested for 16 days at 1 °C, then ripened at 20 °C. In the following season, fruit from another orchard were treated with hot water at 39–42 °C for 20–30 min, disinfested as above, then ripened at 16 °C. In both seasons, HWT significantly reduced skin damage caused by cold disinfestation, with 40 °C for 30 min, 41 °C for 20–30 min and 42 °C for 25–30 min giving the greatest reduction. Hot water treatments also reduced body rots in ripe fruit, with 40 and 41 °C for 30 min being consistently the most effective. Treatment at 42 °C increased body rots compared to the other HWTs in one season, and there was no benefit of HWT times longer than 30 min. The severity of vascular browning (VB) and mesocarp discolouration (MD) in ripe fruit was generally low, and increased following cold disinfestation. Hot water treatments reduced VB severity but had no effect on MD. Treatment at 41 °C for 25–30 min and 42 °C for 25 min increased the percentage of externally acceptable fruit (less than 5% of the skin area with defects) from 0 to about 80% 3 days after removal from disinfestation. The same treatment also increased the percentage of ripe fruit with acceptable flesh quality (less than 5% of the flesh with rots or disorders) from 0 to 16–20%, due mainly to reduced body rots. These results indicate the commercial potential of HWTs of about 41 °C for 25–30 min, or 42 °C for 25 min to improve avocado external and internal fruit quality following cold disinfestation.

The impact on postharvest responses, of preharvest exposure of fruit and vegetables to direct sunlight, with associated high tissue temperatures, is reviewed. Fruit and vegetable flesh temperatures well above 40°C have been recorded in direct sunlight in a wide range of crops in both hot and temperate climates. These high temperatures, both in terms of diurnal fluctuations and long-term exposure, can result in differences in internal quality properties such as sugar contents, tissue firmness, and oil levels, as well as in mineral content differences. Fruit with different temperature histories will also respond differently to postharvest low temperatures and heat treatments used for insect disinfestation. For example, avocado fruit from exposed sites on a tree have less chilling injury, whereas more chilling damage is found in exposed tissues of citrus and persimmons. Mechanisms of high temperature effects on postharvest responses are discussed, including the role of heat shock proteins, membrane damage, and skin characteristics. Differences in exposure of fruit on the tree may be responsible for much of the wide variation commonly found in fruit with regard to at-harvest quality, ripening and postharvest behaviour.

Several lily cultivars from the three main groups were screened for response to ethylene. The vase life of most Oriental hybrid and Lilium longiflorum cultivars was unaffected by ethylene exposure. However, some Asiatic hybrids showed minor responses, as noted for cultivars ‘Apeldoorn’, ‘Goldena’, ‘Elite’ and ‘Mona’. Endogenous ethylene production by all lily cultivars tested was close to or below the limits of detection. CO2 production rates during vase life of 7 days at 20°C varied from 0.5–1.5 μmol kg−1 s−1, with Asiatic hybrids having rates in the upper end of the range. No climacteric increase in ethylene or CO2 production was detected during 7 days at 20°C. Vase life of two Asiatic hybrids (‘Cordelia’ and ‘Prato’) was not affected by a wide range of ethylene concentrations for varying durations, except at the highest concentration and duration of ethylene exposure tested, when vase life was reduced by only about 10–20%. For those Asiatic lily cultivars responding to ethylene exposure, the main effects were caused by high ethylene levels, with a reduced degree of flower opening and percentage of buds which opened. Both these factors influence vase life determination of stems, although quality of the individual flower buds was often less affected by ethylene exposure, as evidenced by similar or extended display life (the period flowers are open and of optimum quality) in ethylene-treated flowers. Pre-treatment of stems with Chrysal® or silver thiosulphate (STS) had little effect on the vase life of flowers subsequently exposed to ethylene. Pre-treatment with 1-methylcyclopropene (1-MCP) did not generally extend the vase life or improve flower quality of the Asiatic or L. longiflorum cultivars tested, although exposure to ethylene did reduce vase life of ‘Elite’ and ‘Cordelia’ by 1.5 days compared with flowers pre-treated with 1-MCP. For ‘Cordelia’, in vivo 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase activity was high, indicating that the enzymatic machinery for ethylene production is present even although endogenous levels were difficult to detect. Generally, ethylene exposure had little effect on cut flower quality or senescence of many of the lily cultivars examined, even when present at high concentrations. This is at variance with industry recommendations that lily flowers be treated with an ethylene antagonist prior to presentation at auction.