`Honeycrisp' apples (Malus × domestica) were harvested over 3-week periods in 2001 and 2002. Maturity and quality indices were determined at harvest. Fruit quality was evaluated after air storage [0.0 to 2.2 °C (32 to 36 °F), 95% relative humidity] for 10-13 weeks and 15-18 weeks for the 2001 and 2002 harvests, respectively. Internal ethylene concentrations (IEC), starch indices (1-8 scale), firmness and soluble solids content (SSC) did not show consistent patterns of change over time. Starch hydrolysis was advanced on all harvest dates, but it is suggested that a starch index of 7 is a useful guide for timing harvest of fruit in western New York. After storage, firmness closely followed that observed immediately after harvest, and softening during storage was slow. No change in SSC was observed during storage in either year. Incidence of bitter pit and soft scald was generally low and was not affected consistently by harvest date. The incidence of stem punctures averaged 18.5% over both years, but was not affected by harvest date. Development of stem end cracking in both years, and rot development in one year, increased with later harvest dates. A panel of storage operators, packers, growers, and fruit extension specialists evaluated the samples for appearance and eating quality after storage, and results suggested that a 2-week harvest window is optimal for `Honeycrisp' apples that are spot picked to select the most mature fruit at each harvest.
James M. Wargo and Chris B. Watkins
Lina Mayuoni and Ron Porat
achieve a final concentration of 4 μL·L −1 . Ethylene concentrations were verified by gas chromatography as described by Porat et al. (1999) . The tanks were flushed daily to ensure that accumulated carbon dioxide levels did not exceed 0.2%. Control fruit
Francisco E. Loayza, Michael T. Masarirambi, Jeffrey K. Brecht, Steven A. Sargent, and Charles A. Sims
storage after the application of different doses of exogenous ethylene to unripe mangoes ( Mangifera indica ); this study revealed that not only duration but also higher concentration of exogenous ethylene treatment induced greater production of ethylene
Yusuke Kubo, Shinobu Satoh, Haruka Suzuki, Toshinori Kinoshita, and Nobuyoshi Nakajima
adaxial cells grow faster than abaxial cells. Two theories of the mechanism of epinasty have been proposed. In one, ethylene affects auxin transport, causing the concentration on the adaxial side of petioles to become higher than that on the abaxial side
Satoru Kondo and Yusuke Takano
Effects of the synthetic auxin 2,4-DP on fruit ripening of `La France' pear (Pyrus communis L.) on `Quince C' (Cydonia oblonga Mill. rootstock) were investigated. A solution of 2,4-DP at 90 μL·L-1 was applied 143, 151, and 159 days after full bloom (DAFB) to whole trees and compared with nonstored nontreated fruit and stored nontreated fruit (harvested 165 DAFB). Internal ethylene concentration in 2,4-DP-treated fruit increased more than in nonstored nontreated fruit and the level was higher the earlier the application time. Fruit firmness decreased earliest for fruit treated with 2,4-DP at 143 DAFB, followed by 151 DAFB-treated fruit and then 159 DAFB-treated fruit. In the nonstored nontreated fruit, firmness also showed a slight decrease with time. In all 2,4-DP treatments, water-soluble polyuronide (WSP) increased with ripening and hexametaphosphate-soluble polyuronide (HMP) and HCl-soluble polyuronide (HP) concentrations decreased. Most notably, WSP concentration increased earliest in fruit treated with 2,4-DP at 143 DAFB. Total concentration of neutral sugars from cell walls in each treatment decreased with time, and the levels in fruit treated with 2,4-DP at 143 DAFB were lowest at each sampling time. Arabinose concentrations were high compared with other neutral sugars throughout fruit ripening for each treatment, while glucose concentrations were high in nonripened fruit. At 193 DAFB, ≈85% of the fruit treated with 2,4-DP at 143 DAFB reached edible condition (firmness not more than 0.4 N·mm-2) on the tree. Furthermore, ≈85% of the fruit treated with 2,4-DP at 151 DAFB reached edible condition on 200 DAFB and close to 100% of the fruit treated with 2,4-DP at 159 DAFB on 207 DAFB. When ripened in a controlled room at 20 °C and 90% relative humidity after 2,4-DP treatment, the fruit treated earliest reached edible condition the soonest. Results demonstrate that 2,4-DP treatment can be used as an effective method of producing good quality fruit ripened on the tree, and that 2,4-DP may be an adequate replacement for cold storage conditioning to induce ripening capacity. Chemical name used: 2,4-dichlorophenoxy-propionic acid (2,4-DP).
Lan-Yen Chang and Jeffrey K. Brecht
. Ethylene and carbon dioxide concentrations were determined by injecting a 3-mL sample of headspace into a Varian CP-3800 gas chromatograph (Varian Inc., Walnut Creek, CA) equipped with a pulsed discharge helium ionization detector (PDHID) and a thermal
Samuel S. Liu and Yong-Biao Liu
ethylene absorbents, the internal quality and injury were significantly correlated with lettuce weight. ANOVA showed that the heavier the lettuce, the higher the percentage of lettuce heads with internal injuries and the lower the internal quality. The
Sylvia M. Blankenship, Michael Parker, and C. Richard Unrath
`Fuji' apples (Malus domestica Borkh.) were harvested at three maturities for three consecutive seasons. Fruit firmness, soluble solids concentration, starch—iodine index (SI), and internal ethylene concentration were measured at harvest. Fruit were stored in 0 °C air storage for 8 months. Fruit firmness and other maturity indices were measured monthly during storage. Using a stepwise regression procedure, harvest maturity indices were used to predict firmness after air storage. When all maturity indices measured were represented in the model, R 2 = 0.29, 0.34, and 0.26 at 4, 6, and 8 months, respectively. Use of only SI and fruit firmness in the model gave R 2 values of 0.25, 0.29, and 0.24 for 4, 6, and 8 months, respectively. Although R 2 values were low, they were highly significant. The model using fruit firmness and SI resulted in the best fit. Thus, an equation was developed using months of air storage, firmness, and SI at harvest. Actual firmness values correlated fairly well with predicted firmness values, usually within ≈5 N. On Washington apples, predicted values were 4.3 and 3.7 N too low compared to actual firmness values after 3 or 5 months' storage. In 1993, when predicted and actual firmness values were compared for Pennsylvania apples, predicted values ranged from 2.6 to 8.3 N too high after 3 months' storage, depending on harvest date. In 1994, Pennsylvania fruit stored 4 months had predicted values 0.5 N too high to 6.3 N too low, depending on harvest date. It may be possible to develop and refine models for an apple variety that would be applicable to several regions.
Gregory M. Peck, Preston K. Andrews, John P. Reganold, and John K. Fellman
Located on a 20-ha commercial apple (Malus domestica Borkh.) orchard in the Yakima Valley, Washington, a 1.7-ha study area was planted with apple trees in 1994 in a randomized complete block design with four replications of three treatments: organic (ORG), conventional (CON), and integrated (INT). Soil classification, rootstock, cultivar, plant age, and all other conditions except management were the same on all plots. In years 9 (2002) and 10 (2003) of this study, we compared the orchard productivity and fruit quality of `Galaxy Gala' apples. Measurements of crop yield, yield efficiency, crop load, average fruit weight, tree growth, color grades, and weight distributions of marketable fruit, percentages of unmarketable fruit, classifications of unmarketable fruit, as well as leaf, fruit, and soil mineral concentrations, were used to evaluate orchard productivity. Apple fruit quality was assessed at harvest and after refrigerated (0 to 1 °C) storage for three months in regular atmosphere (ambient oxygen levels) and for three and six months in controlled atmosphere (1.5% to 2% oxygen). Fruit internal ethylene concentrations and evolution, fruit respiration, flesh firmness, soluble solids concentration (SSC), titratable acidity (TA), purgeable volatile production, sensory panels, and total antioxidant activity (TAA) were used to evaluate fruit quality. ORG crop yields were two-thirds of the CON and about half of the INT yields in 2002, but about one-third greater than either system in 2003. High ORG yields in 2003 resulted in smaller ORG fruit. Inconsistent ORG yields were probably the result of several factors, including unsatisfactory crop load management, higher pest and weed pressures, lower leaf and fruit tissue nitrogen, and deficient leaf tissue zinc concentrations. Despite production difficulties, ORG apples had 6 to 10 N higher flesh firmness than CON, and 4 to 7 N higher than INT apples, for similar-sized fruit. Consumer panels tended to rate ORG and INT apples to have equal or better overall acceptability, firmness, and texture than CON apples. Neither laboratory measurements nor sensory evaluations detected differences in SSC, TA, or the SSC to TA ratio. Consumers were unable to discern the higher concentrations of flavor volatiles found in CON apples. For a 200 g fruit, ORG apples contained 10% to 15% more TAA than CON apples and 8% to 25% more TAA than INT apples. Across most parameters measured in this study, the CON and INT farm management systems were more similar to each other than either was to the ORG system. The production challenges associated with low-input organic apple farming systems are discussed. Despite limited technologies and products for organic apple production, the ORG apples in our study showed improvements in some fruit quality attributes that could aid their marketability.
Peter J. Dittmar, Jonathan R. Schultheis, Katherine M. Jennings, David W. Monks, Sushila Chaudhari, Stephen Meyers, and Chen Jiang
storage roots harvested from fields with heavy rainfall, which led to our hypothesis that excessive moisture may contribute to internal necrosis. With flooding, roots suffer oxygen deficiency ( Jackson, 1985 ), which can increase the concentration of 1