; Tong et al., 2003 ; Wargo and Watkins, 2004 ) as well as greasiness ( DeLong et al., 2006 ; Delong et al., 2009 ; Watkins et al., 2005 ). Soft scald and soggy breakdown have proven to be serious limitations for air storage of the cultivar but could
Christopher B. Watkins and Jacqueline F. Nock
Jinwook Lee, In-Kyu Kang, Jacqueline F. Nock, and Christopher B. Watkins
Watkins, 2008 ), diffuse flesh breakdown ( Lee et al., 2016 ), core browning ( DeEll and Ehsani-Moghaddam, 2013 ), fruit cracking ( Lee et al., 2016 ), flesh breakdown ( Lee et al., 2013 ), peel greasiness ( Dong et al., 2012 ), and superficial scald
Kenneth R. Summy and Christopher R. Little
obtain near-infrared/red ratios. Sour orange: control ( a ) and sooty mold-infested ( b ; arrow); ‘Bo’ tree leaves: control ( c ), honeydew spotting ( d ; arrow), and sooty mold infested ( e ; arrow); grapefruit foliage: healthy control ( f ) and greasy
James Mattheis and David R. Rudell
soluble solids content, include development of peel greasiness, peel yellowing, and senescent disorders ( Watkins et al., 2004 , 2005 ). ‘Honeycrisp’ is susceptible to the chilling disorders soft scald and soggy breakdown ( Tong et al., 2003 ), but the
Corina Serban, Lee Kalcsits, Jennifer DeEll, and James P. Mattheis
, leather blotch, lenticel breakdown, senescent browning, core browning, internal browning, cavities, greasiness, soft scald, and soggy breakdown) are reported as incidence. Bitter pit was determined as surface lesions <5 mm in diameter with underlying brown
James M. Wargo, Ian Merwin, and Christopher Watkins
`Jonagold' apple often has problems of inadequate red blush development at harvest, and loss of firmness and skin “greasiness” after refrigerated storage. During two growing seasons we tested factorial combinations of three preharvest treatments for managing these problems: 1) N fertilization (no applied N, 34 kg N/ha in May, or 1% (w/w) foliar urea sprays in May and June); 2) mid-summer trunk scoring (girdling); and 3) aminoethoxyvinylglycine (AVG) applications 3 weeks prior to harvest. Fruit were harvested at four weekly intervals each year, and evaluated for size, blush, firmness, soluble solids, ethylene, and starch hydrolysis. Nitrogen delayed blush development in 1998, but not 1999, and there was no difference in fruit surface blush coverage between foliar urea and soil applied N. Nitrogen applications increased fruit size, decreased fruit firmness, and increased post-storage flesh breakdown in 1999. Trunk scoring increased blush coverage and intensity both years, and improved market-grade packouts. Blush increase after trunk scoring was not caused by advanced fruit maturity (based on ethylene and starch indices) in either year, although it did increase skin greasiness slightly. AVG treatments delayed maturity and blush development of `Jonagold' by 7 to 10 days both years, relative to untreated fruit. Flesh firmness increased and greasiness decreased in AVG treated fruit harvested on the same dates as controls. However, in AVG fruit harvested at comparable stages of maturity 7 to 10 days later, firmness and greasiness were equivalent to untreated fruit on the previous harvest date. Trunk scoring and no N fertilizer were effective for improving fruit blush coloration, and AVG for delaying harvest maturity.
F R Harker, C B Watkins, B A Cregoe, P L Brookfield, and W J Bramlage
The apple growing districts of New Zealand are spread across a wide range of latitudes. Differences in growing conditions associated with these various districts may influence the way fruit mature on the tree. In this study, the relationships between background colour and physiological maturity of Royal Gala apples have been compared in four major production areas. Royal Gala apples were strip picked from trees in three orchards during the commercial harvest period Hawkes Bay, Canterbury, Nelson and Otago. The maturity of these fruit was assessed, and fruit stored at 0°C for 12 weeks. Following removal from “storage, the quality of the fruit was assessed paying particular attention to -greasiness. Results from this trial indicate that the relationship between background colour and fruit maturity is not consistent. Indeed, the maturity of apples of a particular background colour may differ according to district and harvest date. Greasiness of fruit was related to harvest maturity in Hawkes Bay. However, fruit from Canterbury and Otago became severely greasy even when harvested at early maturities.
James M. Wargo, Ian A. Merwin, and Christopher B. Watkins
`Jonagold' apples [Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.] often fail to develop adequate red coloration at maturity and become soft and greasy in storage. During two growing seasons, we tested factorial combinations of three preharvest treatments affecting `Jonagold' quality at harvest and after storage: 1) three nitrogen (N) treatments [36 kg·ha-1 soil applied N, 6.9 kg·ha-1 of urea-N (1% w/v) in foliar sprays mid-May and June, or no N fertilizers]; 2) trunk girdling in early August each year; and 3) foliar applications of aminoethoxyvinylglycine (AVG, formulated as ReTain) 3 weeks before the first scheduled harvest. Fruit were sampled at four weekly intervals each year and evaluated for maturity and quality at harvest and after storage. Foliar urea and soil-applied N delayed red color development in 1998 but not 1999, increased fruit size in girdled and nonAVG treated trees in both years, and increased greasiness in 1999 only. AVG reduced fruit greasiness after storage both years. Nitrogen uptake was reduced in the dry Summer 1999, but N treatments still increased poststorage flesh breakdown. Mid-summer trunk girdling increased red coloration and intensity both years and improved market-grade packout. This effect was not caused by advanced maturity, although trunk girdling slightly increased skin greasiness. Girdling reduced fruit size only on trees of low N status. The AVG applications delayed maturity and red color development by 7 to 10 days in both years compared with untreated fruit. In 1998, the combination of AVG and N fertilization delayed red color development more than either treatment alone. Fruit softening and greasiness were reduced in AVG-treated fruit harvested at the same time as untreated fruit, but this effect was not observed when AVG treated fruit were harvested at comparable maturity 7 to 10 days later. Trunk girdling and withholding N fertilizer were the best treatments for enhancing red coloration, and foliar N concentrations of ≈2.0% (W/W) resulted in better packouts compared with higher leaf N levels. AVG was an effective tool for delaying fruit maturity and maintaining fruit quality awaiting harvest, but not for improving red coloration of `Jonagold' apples.
Donald N. Maynard and Donald L. Hopkins
Watermelon (Citrullus lanatus [Thunb.] Matsum & Nakai) fruit are affected by a number of preharvest disorders that may limit their marketability and thereby restrict economic returns to growers. Pathogenic diseases discussed include bacterial rind necrosis (Erwinia sp.), bacterial fruit blotch [Acidovorax avenae subsp. citrulli (Schaad et al.) Willems et al.], anthracnose [Colletotrichum orbiculare (Berk & Mont.) Arx. syn. C. legenarium (Pass.) Ellis & Halst], gummy stem blight/black rot [Didymella bryoniae (Auersw.) Rehm], and phytophthora fruit rot (Phytophthora capsici Leonian). One insect-mediated disorder, rindworm damage is discussed. Physiological disorders considered are blossom-end rot, bottleneck, and sunburn. Additionally, cross stitch, greasy spot, and target cluster, disorders of unknown origin are discussed. Each defect is shown in color for easy identification.
Chris B. Watkins, Randolph M. Beaudry, Terence L. Robinson, and Alan N. Lakso
ReTain™, a commercial plant growth regulator containing aminoethoxyvinylglycine, an inhibitor of ethylene production, was applied 4 weeks before normal harvest to `Jonagold' trees and the effects on fruit maturity and quality at harvest, and quality after air and controlled atmosphere storage was investigated. When fruit were harvested from 3 to 6 weeks after treatment, fruit ripening was inhibited as indicated by lower internal ethylene concentrations, delayed starch hydrolysis, and lower levels of skin greasiness. A number of factors indicated that other aspects of fruit metabolism were affected by the compound. Treated fruit were softer than nontreated fruit at the first harvest, and the benefits of ReTain on firmness appeared only at the later harvests. Also, at each harvest date, average fruit weight of ReTain-treated fruit was lower than nontreated fruit. We have investigated the possibility the ReTain and/or the accompanying surfactant, Silwet, inhibited leaf photosynthesis, thereby leading to altered carbon metabolism. Trees were unsprayed, or sprayed with surfactant, and ReTain plus surfactant. No treatment effects on photosynthesis were detected. However, leaf photosynthesis rates were generally low and quite variable. Measurements of fruit diameter confirmed that the increase in fruit volume following treatment was ≈2% less on the ReTain plus surfactant-treated fruit than nontreated fruit. The increase in fruit volume for the Silwet treatment was ≈1.5% less than in untreated fruit. The data indicates a rapid change in fruit volume as fruit changed in color. Inhibition of ethylene by ReTain may be an important factor influencing fruit size.