The Effect of Ethephon, Abscisic Acid, and Methyl Jasmonate on Fruit Ripening in Rabbiteye Blueberry (Vaccinium virgatum)

Abstract

Ripening in blueberry fruit is irregular and occurs over an extended period requiring multiple harvests, thereby increasing the cost of production. Several phytohormones contribute to the regulation of fruit ripening. Certain plant growth regulators (PGRs) can alter the content, perception, or action of these phytohormones, potentially accelerating fruit ripening and concentrating the ripening period. The effects of three such PGRs-ethephon, abscisic acid, and methyl jasmonate-on fruit ripening were evaluated in the rabbiteye blueberry (Vaccinium virgatum) cultivars 'Premier' and 'Powderblue'. Application of ethephon, an ethylene-releasing PGR, at 250 mg L −1 when 30-40% of fruit on the plant were ripe, accelerated ripening by increasing the proportion of blue (ripe) fruit by 1.5-1.8-fold within 4 to 7 days after treatment in both cultivars. Ethephon applications did not generally alter fruit quality characteristics at harvest or during postharvest storage, except for a slight decrease in juice pH at 1 day of postharvest storage and an increase in fruit firmness and titratable acidity after 15 days of postharvest storage in Powderblue. In Premier, ethephon applications decreased the proportion of defective fruit at 29 days of postharvest storage. Abscisic acid (600-1000 mg L −1 ) and methyl jasmonate (0.5-1 mM) applications did not alter the proportion of ripe fruit in either cultivar. These applications also had little effect on fruit quality characteristics at harvest and during postharvest storage. None of the above PGR applications affected the development of naturally occurring postharvest pathogens during storage. Together, data from this study indicated that ethephon has the potential to accelerate ripening in rabbiteye blueberry fruit, allowing for a potential decrease in the number of fruit harvests.Horticulturae 2018, 4, 24 2 of 13 harvested three to five times depending on the variety. This makes harvesting a labor intensive and expensive component of blueberry production, requiring up to 520 h of labor/acre and costing up to $0.70 per pound of harvested fruit [7][8][9]. Concentrating the period of ripening could help reduce the required number of harvests and reduce costs associated with production. Ripening is regulated by multiple plant hormones such as ethylene, abscisic acid, auxins, and jasmonates [10]. External applications of plant growth regulators (PGRs) that influence the levels or activity of these plant hormones may alter the progression of ripening and thereby help in concentrating the period of fruit ripening for efficient harvesting. Therefore, understanding the progression of ripening and developing tools such as PGR applications can help in improving the efficiency of blueberry harvesting.Fruit ripening is a coordinated process involving changes in fruit texture, color, flavor, and susceptibility to biotic and abiotic factors [11,12]. Although all fruit display these changes during ripening, fruits can be generally classified into one of two types depending on physiological and bioche...

The Effect of Ethylene on the Color Change and Resistance to Botrytis cinerea Infection in ‘Kyoho’ Grape Fruits

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Transcriptomic and Physiological Analysis Reveals the Responses to Auxin and Abscisic Acid Accumulation During Vaccinium corymbosum Flower Bud and Fruit Development

“…Similar to other berries, ‘O’Neal’ berries initiate growth after successful pollination and fertilization, and expand quickly by cell division, cell expansion, and accumulation of water and assimilates with seed development in several weeks. During fruit growth and development, the transient concentrations of phytohormones may regulate fruit set, development, and maturation as well as cell proliferation, growth and death ( Kumar et al, 2014 ; Wang et al, 2018 ; Fenn and Giovannoni, 2021 ). In this study, cytological, physiological and transcriptomic datasets were used to elucidate the possible regulatory mechanisms underlying flower and fruit development in the southern highbush blueberry cultivar ‘O’Neal’.…”

Exogenous Ethylene Promotes Peel Color Transformation by Regulating the Degradation of Chlorophyll and Synthesis of Anthocyanin in Postharvest Mango Fruit

“…Ethephon [(2-chloroethyl)phosphonic acid, ETH] serves as one of the artificial analogs of ethylene and the role of ETH in fruit ripening has been reported in extensive literature ( 6 ). Previous studies have shown that the application of ETH accelerates the ripening process of tomato ( 7 ), blueberry ( 8 ), pear ( 9 ), fig ( 10 ), and mango ( 11 ). It is well-known that 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxidase (ACO) are two critical enzymes involved in the biosynthesis of ethylene ( 12 , 13 ).…”