bluuebunny/crossref_metadata_2025 huggingface dataset:
325 Evaluation of `Meeker' Red Raspberry Freeze Tolerance using Whole-plant Growth and Root Electrolyte Leakage Viability Tests
Authors: Hummel Rita L. , Bristow Peter R.
Published: February 2019

In Spring 1996, `Meeker' red raspberry root cuttings were planted into a sandy loam soil in 30 cm tall x 27 cm diameter black plastic containers. During Mar. 1997, a second bottomless container was placed over the overwintering canes of half of the plants. The second container was filled with the same sandy loam soil to simulate ridging of the plants. All plants were grown using standard cultural practices on an outdoor, gravel nursery bed. Freeze tolerance of potted whole plants and excised root sections was measured at 5 °C intervals between -5 and -20 °C in a series of laboratory freeze tests conducted during Jan. 1998. Electrolyte leakage data were used to calculate the index of injury for excised roots while whole-plant response to freezing was determined by measuring the subsequent growth of floricane lateral shoots and of primocanes. After 1 month in the greenhouse, results indicated the dry weight of primocanes harvested from plants that were exposed to -20 °C was 56% of the nonfrozen control primocane dry weight. Primocane dry weight from plants exposed to -5, -10 and -15 °C was not different from the controls. Similar results were obtained for the percent of floricanes that were alive and for the dry weight of laterals produced by these floricanes after 3 months in the greenhouse. The whole-plant freeze test results indicated plants at the lowest temperature, -20 °C, were injured but not killed. Root index of injury of single potted plants averaged 5%, 15%, 29%, and 58% at -5, -10, -15, and -20 °C, respectively.
326 High Root-zone Temperature Inhibits Strawberry Reproductive and Vegetative Growth and Development
Authors: Biela Melita Marion , Nonnecke Gail R. , Graves William R. , Horner Harry T.
Published: February 2019

High temperatures are reported to promote day-neutral strawberry (Fragaria ×ananassa) vegetative growth and development and inhibit floral and fruit development, thereby imposing geographic and temporal limitations on fruit production. Day-neutral strawberry response to air temperature has been researched, but specific responses to temperature in the root zone have not. In a 1998 greenhouse experiment, 60 `Tristar' plants were grown hydroponically in a system of individual, temperature-controlled pots. A randomized complete-block design with constant root-zone treatments of 11, 17, 23, 29, and 35 °C and 12 replications were used. Stomatal conductance and transpiration rate were significantly lower for plants at 35 °C, compared with plants at all other temperatures. Leaf area and leaf dry mass of plants at 35 °C were five and four times smaller, respectively, than the combined mean for plants in all other treatments. Leaf area of runner tips was 450 and 44.5 cm2 at 11 and 35 °C, respectively, compared with that of plants at all other temperatures, 1552.1 cm2. Fruit dry mass was 14.5, 21.6, 25.5, 29.0, and 3.96 g per plant at 11, 17, 23, 29, and 35 °C, respectively. Root dry mass was highest at 11 and 17 °C and lowest for plants at 35 °C. The number of flowers, fruit, and inflorescences per plant was reduced at 35 °C, as were individual berry fresh mass and diameter. Overall, `Tristar' growth and development were near optimal at 17, 23, and 29 °C.
329 Rubus Plant Growth and Development as Influenced by Two High Summer Heat Environments
Authors: Stafne Eric T. , Clark John R. , Rom Curt R.
Published: February 2019

Seven Rubus cultivars were evaluated at two locations in Arkansas, northwest (Fayetteville) and southwest (Hope), to evaluate plant growth differences under high and very high summer temperature conditions. Temperatures during the hottest month (July) averaged 34 °C and 38 °C for Fayetteville and Hope, respectively. Growth; leaf area and number; and fresh and dry weights of leaves, stems, and roots were measured on the containerized raspberry cultivars Autumn Bliss, Dormanred, Heritage, Nova, Reveille, and Southland and the blackberry cultivar Arapaho. Growth measurements included number of canes per plant, number of laterals per cane, cane length, node number, and internode length. Measurements were taken monthly from June through September. Leaf areas were done after all growth measurements were taken at both locations in September. Variation occurred among cultivars and locations for leaf area, fresh and dry weights, growth, and leaf number. Plant death occurred at the Hope location, with `Heritag', `Reveille', and `Southland' all having plant mortality, while `Dormanred' and `Arapaho', both southern-adapted cultivars, had the greatest fresh and dry weights. The Fayetteville location had no plant loss after initial emergence in spring, and this more moderate environment probably contributed to higher plant survival. Our data indicated that only `Dormanred' and `Arapaho' achieved adequate survival and growth in the very high temperatures of the Hope location, whereas other cultivars (Reveille and Southland) with some southern U.S.-adapted germplasm, showed poor adaptation to the environments of our study. Our findings reflect the impact of high heat on non-adapted germplasm and reveal information on adaptation levels needed for parental consideration in breeding for southern conditions.
330 Effects of Calcium Salts on Chilling Tolerance in Cucumber Seedling Roots
Authors: Ozden Mustafa , Jennings Paul H.
Published: February 2019

The effects of calcium salts and concentrations from 25 to 200 mM on the induction of chilling tolerance in cucumber roots were studied using total root growth, electrolyte leakage, lipid peroxidation, and activities of antioxidant enzymes as indicies of chilling injury. Cucumber seeds `Poinsett 76' germinated at 25 °C for 36 h were treated with calcium sulfate, calcium nitrate, and calcium chloride for 2 h at 25 °C. After incubation, treated seedlings were rinsed with distilled H2O and chilled at 2 °C for 72 or 96 h with or without re-warming at 25 °C. Roots of CaSO4-treated cucumber seedlings exhibited less chilling injury at all concentrations, when exposed to 72- or 96-h chilling periods with a 72-h re-warming period as shown by greater root growth compared to the chilled control. Concentrations of CaCl2 and Ca(NO3)2 above 100 mM resulted in significant root growth inhibition. Electrolyte leakage (EL) was significantly reduced by CaSO4 up to 150 mM under chilling conditions and all calcium salt treatments reduced malondialdehyde (MDA) levels in seedling roots up to 150 mM. However, at 150 mM CaSO4 both EL and MDA values of 72 h chilled and re-warmed roots were at their lowest levels compared to the control and other treatments. Both superoxide dismutase and catalase activities of seedling roots decreased under chilling conditions compared to the nonchilled control, although the reduction was less in the presence of CaSO4. Peroxidase and glutathione reductase activities increased under chilling conditions and were generally reduced in the presence of calcium salts compared to the chilled control.
338 Timing of Onion Bulb Formation under Field Conditions in New York in Relation to Temperature, Photoperiod, and Cultivar
Authors: Wien H.C. , Orenstein B.S. , Ellerbrock L.A.
Published: February 2019

Although it has been known since the 1930s that long photoperiods and high temperatures hasten bulb formation in onions, the time at which onion cultivars under field conditions in New York start forming bulbs has not been previously reported. In the 1997 and 1998, onion cultivars were seeded in three commercial onion production areas at normal early spring planting dates. In 1998, a time-of-planting study was carried out in Ithaca, N.Y., in which three transplanted crops and three direct-seeded crops were established at monthly intervals beginning at the end of March. Bulb ratios (bulb diameter: neck diameter) were measured at 2-week intervals during the season in all plantings. Initiation of bulbs (assumed to occur 3 weeks before bulb ratio reached 2) was then related to the photoperiod and air temperature up to that point. A comparison of early, mid-season, and late cultivars indicated that bulbs are initiated in commercial plantings in New York at close to the longest day of the year (15.6 h), at a time when mean temperature is still rising. In the time of planting study, delay of planting resulted in fewer days from emergence to bulb initiation and a reduction in growing degree-day accumulation. If planted later than 15 June, some cultivars failed to initiate bulbs, but others, such as `Quantum' and `Winner', initiated bulbs but did not mature them. The results indicate that photoperiod appears to be the primary factor for the initiation of bulbs, but that bulb initiation can be modified strongly in some cultivars by temperature.
341 Carbohydrate Concentration in Antirrhinum majus L. Flower, Leaf, and Stem Tissue
Authors: Schroeder Kenneth R. , Stimart Dennis P.
Published: February 2019

A phenol-sulfuric acid assay was used to quantify non-specific neutral carbohydrates in Antirrhinum majus L. flowering stems of three inbreds and their hybrids. Flowering stems 40 cm long were harvested with five to six florets open and flower, leaf, and stem tissue separated, freeze-dried, and finely ground. Carbohydrates were extracted from the tissue with 95% ethanol in a 70 °C water bath and combined with a 5% w/v phenol solution and concentrated sulfuric acid. Glucose equivalents were determined with a spectrophotometer at absorbance of 490 nm. Averaged over tissue type, results were genotype dependent, ranging from 213 to 291 μg glucose equivalent per mg dry tissue with a LSD0.05 = 13. Flowers had the highest concentration of 340 μg/mg dry tissue, followed by stems, then leaves with 36% and 38% lower concentrations, respectively. Carbohydrate concentrations in two inbreds were compared when grown under cool (16 °C) and warm (29 °C) conditions. A genotype x environment interaction exists with inbred 3 exhibiting no reduction, 6% increase, and a 45% reduction in carbohydrate concentration when grown in warm conditions, while inbred 2 exhibited 15%, 23%, and 37 % reductions for flowers, leaves, and stems, respectively. Overall, there were 10% and 21% reductions in carbohydrate concentration for inbreds 2 and 3, respectively, when plants were grown under warm conditions.
342 Shading Influences the Growth and Development of Pawpaw Seedlings Grown Outside
Authors: Pomper Kirk W. , Jones Snake C. , Reed Eddie B.
Published: February 2019

In an effort to determine the optimal light level for growing pawpaw [Asimina triloba (L.) Dunal] seedlings outside, seedlings were germinated in a greenhouse until the two- to three-leaf stage, at which time they were placed outside and shade treatments were imposed that reduced incident light intensity by 30%, 55%, 80%, and 95%. Control seedlings were left unshaded outside. A randomized block design was used, with 20 replicate seedlings in each experimental treatment per block. Plants were destructively harvested 11 weeks after the start of the experiment. After 11 weeks, the height and number of leaves per seedling were about 35% higher with light to moderate shading (30%, 55%, and 80%) than in control (unshaded) seedlings. Shoot and leaf dry weights of seedlings grown in 30%, 55%, and 80% shade were almost 2-fold greater than control plants. Root dry weight of seedlings in 30% and 55% shade was 2-fold higher than in control plants. Total plant biomass was greatest in the 30%, 55%, and 80% shade treatments, about 2-fold higher than control plants. Total leaf area per seedling increased significantly with up to 80% shading. Seedlings growing under 95% shading had fewer and smaller leaves and reduced biomass production compared to control plants. There was a trend for shaded plants to display a higher leaf chlorophyll content than control plants. Overall, the best seedling growth was achieved in the 30% and 55% shade treatments outdoors.
345 Seed Germination of Inland Saltgrass
Authors: Harrington Judy , Reid Scott
Published: February 2019

Distichlis spicata var. stricta (Torrey) Beetle is a native grass that tolerates salt, high pH, and some heavy metals. It has been proposed for use in several challenging environments, including mine spoils and salt-impacted areas of golf courses, but its widespread use has been hindered by several factors, one of which is seed dormancy. Dormancy appears to be coat-imposed and can be overcome by scarification in relatively young seed lots. Thirteen-year-old seeds germinated better without scarification. Seeds were tested at several constant and alternating temperatures. Temperatures around 30 °C seemed to give the highest percentage germination, approaching the viability that was shown by tetrazolium chloride tests for each seed lot. Alternating temperatures increased the germination of unscarified seeds but not as much as scarification did. Light appears to be unnecessary for germination.
349 Studies on Postharvest Performance of Cut Racemes of Big Bend Bluebonnet
Authors: Mackay W.A. , Sankhla D. , Davis T.D , Sankhla N.
Published: February 2019

Racemes of Big Bend bluebonnet (Lupinus havardii Wats.), a winter annual native to far west Texas with attractive blue flowers, are currently being produced commercially as a specialty cut-flower crop. Our studies indicated that the key determinants of postharvest longevity and performance are flower abscission and flower senescence, both of which can be influenced by ethylene. Therefore, this study was undertaken to evaluate the role of some ethylene biosynthesis inhibitors (aminooxy acetic acid = AOA; cobalt = CO++; salicylic acid = SA) and an ethylene action inhibitor (silver thiosulfate = STS) on flower abscission and flower senescence of bluebonnet racemes. Depending on the concentration used (10 μM - 1 mM), AOA and CO++ exhibited variable effects on flower abscission, flower senescence and vaselife. SA (10-100 μM) slightly delayed senescence but did not affect abscission, while higher levels of SA (500 μM - 2 mM) slightly promoted abscission and also significantly enhanced the senescence of flowers on cut racemes. The effects of SA were found to be pH-dependent. However, STS nearly eliminated flower abscission and enhanced vaselife. The results also demonstrated that the abscission of bluebonnet flowers, in particular, is highly sensitive to ethylene.
351 Use of Promalin (GA4+7 and BA) Sprays to Prevent Cold Storage-induced Leaf Yellowing and Abscission in `Stargazer' Hybrid Lilies
Authors: Ranwala Anil P. , Miller William B.
Published: February 2019

Our previous research has demonstrated preventive effects of foliar sprays of growth regulators containing GA4+7 (ProVide or Promalin) on cold storage-induced leaf yellowing and abscission in `Stargazer' hybrid lilies. Further research was conducted to investigate the effective concentrations of Promalin and appropriate timing of promalin sprays. Lilies at “puffy bud” stage were sprayed with promalin at concentrations of 10, 25, 50 or 100 ppm (each GA4+7 and BA) just before placing them at 4 °C for 2 weeks in darkness. Promalin concentrations of 25 ppm or above completely prevented cold storage-induced leaf yellowing occurring during the poststorage evaluation phase in a simulated consumer environment, whereas 10 ppm sprays only partially prevented it. Foliar spray of Promalin (100 ppm each GA4+7 and BA) just before storage at 4 °C for 2 weeks was compared with spraying 2 or 4 weeks before cold storage. While spraying 2 weeks before storage prevented leaf yellowing to the same extent observed in plants sprayed just before cold storage, spraying 4 weeks before storage had very little preventive effect on leaf yellowing. To investigate the effectiveness of promalin sprays with different cold storage durations, puffy-bud stage plants were stored at 4 °C for 1, 2, 3, 4, or 5 weeks in darkness with or without promalin sprays (100 ppm each GA4+7 and BA) before storage. Longer cold storage durations increased the severity of leaf yellowing occurring during poststorage phase. Although promalin was able to prevent leaf yellowing completely up to 2 weeks of cold storage, beyond 3 weeks of cold-storage, effectiveness of promalin diminished with no apparent preventive effect on plants stored for 5 weeks.
354 Development of Off-flavor in Melting Flesh and Nonmelting Flesh Peach Genotypes
Authors: Karakurt Yasar , Huber Donald J. , Sherman Wayne B.
Published: February 2019

Some nonmelting flesh (NMF) peaches develop a characteristic off-flavor during postharvest ripening. A study was conducted using NMF genotypes from the Univ. of Florida breeding program to investigate the off-flavor development in melting flesh (MF) and NMF peach genotypes and to determine the compositional changes associated with the development of off-flavor during postharvest ripening at 8 °C. The study revealed that there were certain chemical components that were consistently associated with the occurrence of off-flavor. Generally, there was a significant increase in total soluble phenolics, polyphenoloxidase (PPO) activity and ethanol content with the increase in the percentage of off-flavored fruit with time in storage at 8 °C in NMF genotypes examined. However, total sugars and total soluble solids decreased significantly during the storage period. These changes in chemical composition of NMF genotypes were not observed in MF genotypes, which did not show off-flavor development. Moreover, highly significant linear correlations were detected between off-flavor development and soluble phenolics, PPO activity, ethanol content, total soluble solids, and sugars in Fla. 92-21C and USDA 87P285, which had the highest percentage of off-flavored fruit. Specifically, soluble phenolics, chlorogenic acid, PPO activity, and ethanol were positively correlated, but soluble sugars and soluble solids were negatively correlated with the off-flavor development. Thus, it is suggested that the accumulation of soluble phenolic compounds and ethanol, and the reduction of soluble solids and sugars contribute to the of off-flavor in NMF genotypes.
356 Leatheriness and Mealiness of Peaches, Their Biochemical Characteristics Related to Fruit Maturity and Storage Temperature
Authors: Ju Zhiguo , Duan Yousheng , Ju Zhiqiang
Published: February 2019

`Huangjin' peaches were harvested at immature, mature, and over-mature stages according to ground color and firmness evaluations, and were stored at 0, 5, and 10 °C, respectively. After 4 weeks of cold storage, immature fruit developed a higher percentage of leatheriness but a lower level of mealiness than mature fruit. Over-mature fruit did not develop leatheriness, but developed a higher percentage of mealiness than mature fruit. Fruit stored at 5 °C developed more mealiness than fruit stored at 0 °C for the same period of storage, while fruit stored at 0 °C developed more leatheriness than fruit stored at 5 °C. When stored at 10 °C, fruit did not develop any leatheriness or mealiness regardless of maturity. Compared with juicy and mealy fruit after the same period of cold storage, fruit with leathery symptoms were significantly firmer following 4 days at 20 °C. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-amino-cyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and β-galactosidase (GAL) activity were lower, and insoluble pectin content was higher, in leathery fruit than that in juicy and mealy fruit. Mealy fruit were as soft as juicy fruit after ripening at 20 °C for 4 days. Their ACO, PG, and GAL activity; ACC; and insoluble pectin content were similar. Results indicated that leatheriness is a typical chilling injury but mealiness is not.
359 Firmness and Force Relaxation Characteristics of Tomatoes Stored Intact or as Slices
Authors: Wu Tianxia , Abbott Judith A.
Published: February 2019

We compared the firmness and force relaxation characteristics of tomato flesh harvested at six maturity stages and stored intact or as 7-mm slices for 0 to 20 days. Three measurements were made on outer pericarp and columella tissue. A 4-mm cylindrical probe provided more consistent firmness measurements (lower percent CV) than a 6.4-mm spherical probe at harvest, and distances of 3 mm were more consistent than 1 mm. Following loading, stress relaxation was recorded for 10 s. Stored tomato samples were tested only with the 4-mm cylindrical probe and distance of 3 mm. Firmness was taken as the maximum force (Fmax) in the loading portion, usually occurring at 3 mm. Fmax of freshly harvested tomatoes ranged from 15 to 2 N for mature green and red tomatoes, respectively. Fmax was closely correlated to area, slope, and force at first peak, i.e., all four parameters measured the same physical property, and was moderately correlated (R > 0.9) to forces at specific relaxation times. Tomatoes stored intact generally had lower CVs than that of those sliced before storage, although there was little difference in average firmness (Fmax) between the two at a given storage time. A three-parameter model was developed to fit the relaxation curves. There was little correlation between Fmax and the three relaxation characteristics (R = 0.6 to 0.0), i.e., the relaxation characteristcs measured different physical properties than did Fmax. The responses of the relaxation characteristcs over storage time were dependent on the initial maturity of the tomatoes, but their values usually differed significantly between tomatoes stored intact or sliced, with tomatoes sliced before storage generally having higher values.
362 Prolonging the Shelf-life of Fresh-cut Tomato Slices through Modified Atmosphere and Low Temperature
Authors: Hong Ji Heun , Gross Ken
Published: February 2019

Fresh-cut produce continues to be a rapidly growing industry. However, there is little information available on storage conditions for many commodities, particularly for fresh-cut tomato slices. A major problem with fresh-cut tomato slices is their short shelf-life. The best method to extend shelf-life is refrigerated storage, preferably around 4 to 5 °C. Unfortunately, tomato tissue is susceptible to chilling injury at such temperatures. Experiments were conducted to compare changes in quality of slices from red tomato (Lycopersicon esculentum Mill.) fruit during storage at 5 or 10 °C under various modified-atmosphere conditions. In this study, we used the fourth uniform slice from the stem end and analyzed for various quality attributes during the storage period. At both 5 and 10 °C storage temperatures, ethylene concentration in containers sealed with Film A (oxygen transmission rate of 60.3 or 77.9 ml per hour per m2 at 1 atm and 99% relative humidity at 5 or 10 °C, respectively) was higher than that sealed with Film B (oxygen transmission rate of 87.4 or 119.4 ml per hour per m2 at 1 atm and 99% relative humidity at 5 or 10 °C, respectively), during storage. In addition, chilling injury, as measured by percent of slices showing some water soaked-areas, in containers sealed with Film B was higher than that of slices in containers sealed with Film A. The percent of visible fungal growth of slices was roughly correlated with the degree of chilling injury, as measured by the percent of slices showing some water soaked-areas. After 13 days of storage at 5 °C, slices stored in containers with a beginning atmospheric composition of 12% CO2 /1% O2 were firmer, compared to slices given the other treatments. After 9 days of storage at 10 °C, no visible fungal growth was observed on slices in containers with a beginning atmospheric composition of 12% CO2/1% O2 or 12% CO2/20% O2. However, slices in containers with a beginning atmospheric composition of air, or 4% CO2/1 or 20% O2 and 8% CO2/1 or 20% O2 did show visible signs of fungal growth at 25%, 33%, 46%, 29%, and 100% of infected slices, respectively. Slices in containers given all treatments, with the exception of 12% CO2/1% O2, had visible fungal growth after 15 days of storage at 5 °C. Slices in containers containing eight slices had less chilling injury and visible fungal growth than those containing four slices. Chilling injury of slices stored in completely enclosed plastic containers, similar to those commonly observed in grocery food stores, was over 7-fold higher than chilling injury observed in slices containers covered with Film A after 12 days of storage at 5 °C. However, there were no significant differences in the amounts of the volatiles we measured, i.e., ethanol, ethyl acetate, hexanol and hexanal, between the two container types. These results suggested that modified-atmosphere packaging storage can extend shelflife, as well as inhibit chilling injury in fresh-cut tomato slices.
365 Induced Modified Atmosphere Maintains Quality of Packaged Fresh-cut Honeydew Cubes
Authors: Bai Jin-He , Watada Alley E.
Published: February 2019

A study was made to determine if induction of modified atmosphere at the time of packaging would be of a benefit to the quality of fresh-cut honeydew cubes because the desired gas levels are not attained immediately or at all during the short holding period in modified-atmosphere packages. Fresh-cut honeydew cubes (2-cm cube) were placed in a plastic container underlaid with a water absorbent packet and the container was sealed with a film. The film is coextruded polystyrene and polyethylene (Cryovac), which had oxygen transmission rates of 1448 and 1903ml/m2 per day per atm at 5 °C and 10 °C, respectively. The sealed packages were given one of the following three treatments: 1) the packages were allowed to form their own natural modified atmosphere (nMAP), 2) the internal atmosphere of the packages was flushed with a gas mixture of 5% O2 + 5% CO2 (iMAP), 3) the film was perforated with a needle to have ten 1.5-mm holes (PFP). The packages were stored at 5 °C, 2 days at 5 °C, and transferred to 10 °C or at 10 °C for 2, 4, 7, 9, or 11 days. Quality attributes and microbial population were analyzed after each holding period. The average gas mixture equilibrated to 7% O2 and 9.5% CO2 in nMAP, was unchanged from the induced atmosphere in iMAP, and was close to the ambient condition (air) in PFP. Honeydew cubes were marketable on days 11, 4, and 4 when held in nMAP; on days 11, 4, and 7 when held in iMAP; and unsalable on days 9, 4, and 7 when held in PFP at 5 °C, 10 °C or transferred to 10 °C, respectively. Development of water-soaked lesions and sour odor were the main factor affecting marketability of the cubes. The decreasing pH, chroma and `L' values and increasing hue angle, mesophilic aerobic microrganism, and yeast population was retarded in both of nMAP and iMAP.
368 Responses of `d'Anjou' and `Bartlett' Pear Fruit to Postharvest 1-Methylcyclopropene (MCP) Treatment
Authors: Fan Xuetong , Argenta Luiz , Mattheis James
Published: February 2019

`Bartlett' and `d'Anjou' pear fruit were treated after harvest with MCP at 0, 0.01, 0.1 or 1 mL•L-1 and then stored at 1 °C. After storage, half of the fruit was continuously exposed to 10 mL•L-1 ethylene for 7 days in a flow-through system at 20 °C. A treatment concentration effect was evident for both respiration and ethylene production, all MCP concentrations reduced respiration and ethylene production by `d'Anjou' and `Bartlett' fruit compared to controls. Fruit quality changes in `d'Anjou' and `Bartlett' fruit were delayed by MCP treatment. Firmness and titratable acidity were higher through 4 months storage for `Bartlett' fruit treated at the two higher MCP rates. After 2 months, `Bartlett' fruit treated at the two higher MCP rates remained green, but, after 4 months, all fruit were yellow. Loss of firmness and titratable acidity was also reduced following MCP treatment of `d'Anjou' fruit. Yellowing of `d'Anjou' fruit was prevented by MCP treatment, even when fruit were exposed to ethylene after removal from storage. Poststorage ethylene exposure did not overcome the effects of MCP. Development of superficial and senescent scald was prevented by MCP treatment.
369 Relationship Between Ethylene Production and Accumulation of Cuticular Constituents in `Delicious' Apples During Fruit Ripening at Room Temperature
Authors: Ju Zhiguo , Bramlage William J.
Published: February 2019

Developmental changes in total cuticle and cuticular constituents were studied with `Delicious' fruit. Total wax (0.31 mg/cm2) and total cutin (0.54 mg/cm2, including carbohydrate polymers) were low in young fruit. They increased during fruit growth and reached 1.41 and 2.47 mg/cm2 of fruit peel at harvest, respectively. During fruit ripening at 20 °C, total cutin did not change, but total wax increased rapidly and reached 2.15 mg•cm-2 at 6 weeks. The increase of cuticular wax paralleled the increase of internal ethylene in fruit. Wax was separated by column chromatograph into four portions, hydrocarbons and wax esters, free alcohols, free fatty acids, and diols. More than half of the diols was ursolic acid. During fruit development, more hydrocarbons and diols accumulated in cuticle than free fatty acids and alcohols. During fruit ripening, all of the four portions increased, coincident with the climacteric rise in ethylene, but the increase rates of free fatty acids and alcohols were higher than those of other portions. Aminoethoxyvinylglycine (AVG, 220 mg•L-1) preharvest treatment inhibited internal ethylene synthesis to below 0.5 μL•L-1 during 6 weeks at 20 °C, and also inhibited wax accumulation. Ethephon (200 mg/L) preharvest treatment increased ethylene production and accelerated wax accumulation. α-farnesene accumulation coincided with increased internal ethylene and paralleled free fatty acid and alcohol accumulation.
371 Enhancing Anthocyanin Production and Maturity Uniformity of Apples Without Over-ripening
Authors: Wang Zhenyong , Dilley David R.
Published: February 2019

Multiple harvests are often necessary to achieve maximum yield of well-colored high-quality apples. This is true for most cultivars, and particularly for `Gala'. Multiple harvests add significantly to the cost of producing apples. We tested our hypotheses that anthocyanin production of ReTain™-treated apples may be enhanced by ethephon without overly stimulating other ripening processes and ReTain™ may promote uniform maturation of apples within and between trees by delaying maturation and ripening processes. Experiments were conducted with `Gala', `Empire', and `Jonagold' apples at the MSU CHES in 1997 and 1998 employing the rootstock/training systems research plot. Treatments were 1) ReTain™ (50g/ac.) applied 3 to 4 weeks before harvest, 2) ReTain™ followed by ethephon (3/4 pt/ac.) applied 1 to 2 weeks before harvest, 3) ethephon, and 4) control (Silwet® L-77 surfactant only). ReTain™ applied alone delayed the onset of the ethylene climacteric and red color development of `Gala' apples. ReTain™ followed by ethephon delayed the onset of the ethylene climacteric and red color development at the commercial harvest date was not significantly affected. Similar results were obtained with the `Empire' and `Jonagold'. Results with ReTain™ and ReTain™ + ethephon in 1998 on `Gala', `Empire', and `Jonagold' apples were more profound than in 1997; we attribute this to less environmental stress on the trees, which were well-irrigated in 1998. The ripening-related effects of treatments were reflected in the storability of fruit 1997 in air and particularly during CA storage where the action of ethylene in ripening can be attenuated. ReTain™ - and ReTain™ + ethephon-treated fruit were still at preclimacteric ethylene levels after 6 months in CA with excellent retention of flesh firmness and shelf-life, while ethephon and control fruit had higher ethylene levels and softened more during storage and shelf-life evaluation.
372 1-MCP-mediated Ripening Changes in `McIntosh' Apples
Authors: Rupasinghe H.P.V. , Murr D.P. , Paliyath G.
Published: February 2019

`McIntosh' apples were treated at 20 °C with 0.0, 0.01, 0.1, 1.0, 10, and 100 ppm 1-methylcyclopropene (1-MCP; EthylBloc™) a day after harvest for 18 h and stored at 0 °C in air. Apples were also continuously exposed to 0.0 and 25 ppm 1-MCP under controlled atmosphere (CA; 0 °C in 4.5 kPa CO2 and 3 kPa O2) by re-establishing the initial concentration at week 9 and 17. The threshold concentration of 1-MCP at 20 °C to inhibit de novo ethylene production in apple fruit was determined to be 1.0 ppm. Interestingly, the ethylene antagonist completely inhibited (99.67%) ethylene production in apples, which were removed from 0 °C in air and CA after 9 weeks and held at 20 °C up to 6 days. Overall, ethylene production was 10- to 100-fold less in apples treated with 1 ppm and above 1-MCP than in untreated apples. 1-MCP-treated apples showed less softening; fruit firmness was 2-4 Lb higher compared to untreated apples. Total soluble solids of apples was not affected by 1-MCP treatment. Total hydrophobic volatiles, including the sesquiterpene hydrocarbon α-farnesene, from apples measured by SPME/GC showed an inverse relation to 1-MCP concentration. Contents of α-farnesene and its putative superficial scald-causing catabolite, conjugated triene alcohol, in the skin were reduced 60% to 90% by 1-MCP. However, 1-MCP did not suppress the incidence of scald or other disorders, e.g., stem cavity, browning and brown core, in `McIntosh' apples.
376 Cuticular Phenolics and Scald Development in `Delicious' Apples
Authors: Ju Zhiguo , Bramlage William J.
Published: February 2019

Effects of fruit maturity, aminoethoxyvinylglycine (AVG) and 2-chloroethylphosphonic acid (ethephon) preharvest treatments, and storage conditions on cuticular phenolic concentration, α-farnesene oxidation, and scald susceptibility of `Delicious' apple were studied. Advanced maturity and ethephon reduced scald. AVG totally inhibited scald when the AVG-treated fruit were stored in low-ethylene room (<1 μL•L-1). In commercial room (ethylene >5 μL•L-1), however, AVG did not reduce scald. Advanced maturity and ethephon did not alter α-farnesene accumulation but significantly reduced conjugated triene (CT281) formation. AVG reduced α-farnesene and CT281 accumulation to very low levels in low-ethylene room but not in commercial room. Both advanced maturity and ethephon increased free phenolics in fruit cuticle, while AVG reduced them. Free cuticular phenolics increased during early storage in ethephon-treated and control fruit but not in AVG-treated fruit. Overall, free phenolics in fruit cuticle negatively correlated with formation of CT281 and scald susceptibility of apples. Neither fruit maturation nor AVG or ethephon treatment significantly affected lipid-soluble antioxidant concentration in fruit cuticle.
379 Biochemical Barriers Induced by UV Light and Botrytis cinerea in Postharvest Tomato
Authors: Charles Marie-Therese , Goulet Alain , Castaigne Francois , Arul Joseph
Published: February 2019

Hormic dose of ultraviolet light (3.7 kJ•m-2) induced disease resistance in tomato fruit. The biochemical nature of induced resistance by UV light was investigated by histochemical techniques. Ultraviolet light induced plasmolysis of the epicarp and few mesocarp cell layers, and collapse of these cell layers led to the formation of cell wall stacking zone (CWSZ). The treatment also stimulated the biosynthesis of phenolic compounds (Prussian blue reaction) in the epicarp and mesocarp cells. Biochemical reinforcement of the cell wall through lignification (Maule test) and suberization (berberine fluorescence) was also induced. These responses originating from the activation of phenylpropanoid path were principally localized in the CWSZ and were induced before inoculation by B. cinerea. The intensity of these responses was significantly increased in UV-treated tissue in response to infection. These responses were also induced in the inoculated control tissue but were either less substantial (phenolics, lignification, and suberization) or delayed.
380 Chlorophyll Fluorescence and Prediction of `Iceberg' Lettuce Shelf-life
Authors: Schofield R. Andrew , DeEll Jennifer R. , Murr Dennis P.
Published: February 2019

Chlorophyll fluorescence responds to a range of environmental stresses that affect horticultural crops. This technique has been used successfully to evaluate the quality of commodities after exposure to a number of postharvest stresses such as chilling, heat, and atmospheric stress. As well, chlorophyll fluorescence measurements have been incorporated as the main characteristics in shelf-life prediction models. Our objective was to evaluate the use of chlorophyll fluorescence measurements at harvest to predict the shelf-life of `Iceberg' lettuce. It was hypothesized that storage potential is influenced by the degree of stress induced by field conditions and that different cultivars, although grown under the same conditions, experience varying degrees of stress that can be detected by fluorescence measurements at harvest, even in the absence of visual differences in quality. The utility of fluorescence measurements was limited by inconsistencies in the development of the heads, such as maturity and leaf formation, and by variation among different areas of the same leaf. Fluorescence data from a homogeneous group of heads revealed that the variation associated with different areas of the same leaf was larger than that associated with measurements from different heads. Also, fluorescence readings from one leaf differed from those taken from any non-adjacent leaves. These sources of variation, along with strong cultivar-dependant differences in the fluorescence signal, were quite large, and hence, any trends in fluorescence measurements related to storage potential were not observed. Therefore, chlorophyll fluorescence at harvest does not appear to be a good predictor of lettuce storability.
381 Differential Leaching of Anthocyanins during Thermal Processing of Selected Black Bean (Phaseolus vulgaris L.) Genotypes
Authors: Hosfield George L. , Beninger Clifford W.
Published: February 2019

Seed coat color in dry bean (Phaseolus vulgaris L.) is determined by the presence or absence of tannins, flavonoids, and anthocyanins. Black beans contain three main anthocyanins that are responsible for their black seed coat color: delphinidin 3-O-glucoside, petunidin 3-O-glucoside, and malvidin 3-O-glucoside. Leaching of anthocyanins occurs in many black bean genotypes during thermal processing (i.e., blanching and cooking). Black beans that lose their dark color after processing are unacceptable to the industry. Since the marketability of black beans can be adversely affected by thermal processing, an experiment was conducted to ascertain whether pigment leaching was due to qualitative or quantitative changes in anthocyanins during processing. Four black bean genotypes that showed differential leaching of color were investigated. `Harblack' retains most of its black color after processing while `Raven' loses most of its color. `Black Magic' and `Black Jack' are intermediate between `Harblack' and `Raven' in processed color. Bean samples (119 ± 1.5 g) of the four genotypes were thermally processed in 100 x 75-mm tin cans in a pilot laboratory. Seed coats were removed from the cooked beans, freeze-dried, and placed in solutions of formic 10 acid: 65 water: 25 methanol to extract anthocyanins. The extracts were analyzed by HPLC. Although all genotypes retained some color, there were no detectable anthocyanins in seed coats of the cooked beans. In a second experiment, raw beans of each genotype were boiled in distilled water for 15 minutes. All four genotypes lost color during boiling, but `Harblack' retained most of its color and had a five-fold higher concentration of the three anthocyanins than did the other genotypes. `Harblack' may retain color better than other black beans because of physical characteristics of the seed coat.
382 1-Methylcyclopropene Prevents Development of Ethylene-promoted Postharvest Physiological Disorders of Carrot, Broccoli, and Lettuce
Authors: Fan Xuetong , Mattheis James
Published: February 2019

Carrots, broccoli, and lettuce were treated with air, continuous ethylene, 1-methylcyclopropene (MCP), or a combination of MCP before continuous ethylene. The respiration rate of ethylene-treated carrots reached a maximum 4 days after treatment and remained higher compared to controls through 16 days at 10 °C. Ethylene treatment also resulted in an accumulation of isocoumarin. Treating carrots with MCP before ethylene exposure inhibited the increase in respiration rate and accumulation of isocoumarin. MCP treatment reduced broccoli respiration and yellowing compared to controls, indicating that ethylene is involved in the senescence of broccoli. Ethylene exposure stimulated respiration and yellowing of broccoli. Treatment with MCP before continuous ethylene exposure negated the ethylene effects. MCP also inhibited respiration and russet spotting of lettuce stored in ethylene-containing atmospheres. The results indicate MCP can be used to block ethylene-induced isocoumarin accumulation (associated with bitterness) in carrots, yellowing in broccoli, and russet spotting in lettuce.
384 Modified-Atmosphere Packaging of Fresh Produce to Prevent Generation of Anaerobic Environments
Authors: Wendorf Michael , Mir Nazir A. , Beaudry Randolph M.
Published: February 2019

Broccoli tissue, ranging in weight from 7 to 21 g, was sealed in packages made from low-density polyethylene (LDPE) of various thickness and permeability to establish a range of O2 levels in the package headspace. A pouch containing either hydrogen peroxide (H2O2) or water as a control was also sealed in the package. For packages that developed anaerobic atmospheres, inclusion of H2O2 permitted the maintenance of aerobic conditions for up to 3 days at ambient room temperature. These results suggest that the plant tissue is able to actively metabolize the H2O2 vapor to generate O2, which will prevent the development of low-O2 conditions in packaged produce, even under conditions of elevated storage temperature.
392 Postharvest Quality Of Eastern North American Strawberry Cultivars during Short-term Storage
Authors: Koslanund Rumphan , Archbold Douglas. D.
Published: February 2019

Strawberry cultivars grown for “pre-picked” markets need to maintain quality during short-term postharvest storage in contrast to those destined for “U-pick” harvest. However, very little information is available on berry quality during postharvest storage of cultivars grown in matted-row culture in eastern North America. To determine how rapidly berry quality may change and identify cultivars best-suited for pre-picked markets, the postharvest performance of 16 cultivars grown in matted rows was compared. Berries were sampled at harvest, after 3 days of 4 °C storage within sealed plastic bags, and after 3 subsequent days at 20 °C. Quality traits assessed included fruit firmness, color, titratable acidity, pH, soluble solids, and percent weight loss. At harvest, berry quality varied by cultivar and from early to late harvest dates. Berry quality changed very little during 4 °C storage. During the subsequent 20 °C storage, berry quality traits changed more for some cultivars than others. In particular, soft fruit at harvest and/or a rapid decline in berry firmness indicated that several cultivars were not suited for short-term storage. Based on the cumulative data, several cultivars can be identified as better suited for pre-picked markets.
394 Ripening and Postharvest Behavior of Fruit of Two Hylocereus Species (Cactaceae)
Authors: Nerd Avinoam , Gutman Fania , Mizrahi Yosef
Published: February 2019

Fruit growth and ripening and the effect of various storage temperatureson fruit quality were studied in Hylocereus undatus and H. polyrhizus growing in Beer-Sheva (Israeli Negev desert) under greenhouse conditions. Dimensional growth of the fruit had a sigmoid pattern with a negligible growth after the onset of peel color change. The first change in peel color was recorded 24-25 d after anthesis in H. undatus and 26-27 d after anthesis in H. polyrhizus. In both species, peel color turned fully red 4-5 days after first color change (mean temperature for the study period was 26.6 ± 2.1 °C). Parallel to color changes the content of pulp, SSC and soluble sugars increased while firmness and the content of starch and mucilage decreased. The surge in acidity before color change indicated the beginning of ripening processes. In H. polyrhizus fruit, which have a red-violet pulp, the pigment increased in parallel to the development of peel color. The fruit were proved nonclimacteric, and when harvested at close to full color, they kept their marketing quality at least 2 weeks at 14 °C or 1 week at 20 °C. Storage at 6 °C is not recommended because fruit transferred from 6 °C to room conditions lose their firmness and flavor rapidly. In H. undatus chilling injury symptoms appeared.
397 Simple Ripening Model of Sapote Mamey (Pouteria sapota) Fruit
Authors: Diaz-Perez Juan C. , Bautista Silvia , Villanueva Ramon
Published: February 2019

Sapote mamey is a sweet and aromatic tropical fruit that is very perishable. It is a climacteric fruit and has high rates of respiration and ethylene production. Maturity indices for this commodity are difficult to define because fruit show few changes in external appearance as they ripen. The fruit flesh, however, shows large changes in color, firmness, and sugar content measured as soluble solids content (SSC). The objective was to model fruit ripeness from measurements of SSC. We selected SSC because it is easy to measure and because sweetness is an important quality attribute in sapote mamey. Typical values of SSC range from 12% (immediately after harvest) to 30% to 35% (ripe fruit). A linear-plateau model was used to describe the changes in SSC over time of ripening fruit kept at different temperatures. The model assumed that, as fruit ripened, SSC increased at a linear rate reaching a maximum of 30% SSC at the ripe stage after which SSC changed little. From the model we calculated the rate of fruit ripening and the time to reach the ripening stage (30% SSC). The rate of ripening showed a quadratic relationship with storage temperature. Fruit kept at 27, 25, or 20 °C ripened 3.5, 5, or 7 days after harvest. The model can be used to estimate when fruit will reach the ripe stage, as long as we know the initial SSC and storage temperature. This model was constructed from data obtained over 2 years from fruit grown in the state of Morelos, Mexico. It is still to be tested for its applicability on fruit from other growing regions.
398 Effects of Insecticidal Controlled Atmospheres at High Temperature on the Quality of Mango Fruit
Authors: Yahia Elhadi M. , Ortega Dora
Published: February 2019

We have shown in research work also presented in this meeting that insecticidal controlled atmospheres at high temperatures are very efficient in causing in vitro mortality of eggs and third instar larvas, and in vivo mortality of third instar larvas of Anastrepha ludens and A. obliqua. In this work we are reporting on their effect on the quality of mango fruit. Fruit of the cultivar `Manila' were exposed to 0% O2 + 50% CO2 at 40, 42, 43, 44, 45, 46, 47, 48, and 49°C and 50% relative humidity for 160 min, after which they were stored at 10 °C for 20 days and evaluated at different intervals. Fruit exposed at 44°C or more had heat injury, while those exposed at 43°C or less did not show any injury and had similar or better quality than the control. On the basis of our previous results on insect mortality and on the resulted fruit quality reported here (heat injury, color, texture, weight loss), we conclude that 0% O2 + 50% CO2 at 43°C or less for 160 min can be used for the control of A. ludens and A. obliqua in mangoes.