Application of abscisic acid (ABA) at veraison advanced red color development and maintained postharvest quality of ‘Crimson Seedless’ grapes

https://doi.org/10.1016/j.postharvbio.2007.05.017Get rights and content

Abstract

‘Crimson Seedless’ is a popular table grape cultivar, but in warm-climates, its fruits often fail to develop adequate red color, even after they have been treated with ethephon. Application of abscisic acid (ABA) may improve color more effectively than ethephon, but its potential effects on postharvest quality must be considered before recommending its use on table grapes. Therefore, we compared the postharvest quality attributes of grapes treated preharvest with 250 μL L−1 ethephon, the current industry standard, to that of grapes treated with 150 or 300 μL L−1 ABA, or nontreated. Treatment with either ethephon or 150 μL L−1 ABA allowed grapes to be harvested 10 d before nontreated fruit, and fruits treated with 300 μL L−1 ABA attained marketable quality 30 d before nontreated fruit. Early harvest was possible because the treatments induced more rapid coloring of the grapes, and though total yield was not affected by any plant growth regulator (PGR), all PGRs doubled packable yields by improving the color of the grapes. ABA-treated grapes were characterized by superior appearance both in berries and clusters’ rachises compared to ethephon-treated and control grapes. Other quality attributes such as firmness, berry weight, decay incidence, and shatter remained unaffected among treatments. Therefore, ABA is an effective alternative to ethephon for enhancing the color and maintaining postharvest quality of ‘Crimson Seedless’ grapes.

Introduction

In California, most ‘Crimson Seedless’ table grapes (Vitis vinifera L.) are grown in the San Joaquin Valley, a warm-climate region. Often, ‘Crimson Seedless’ grapes fail to achieve the desired level of red color, in part due to high temperatures which inhibit the accumulation of anthocyanins (Spayd et al., 2002), the class of pigments that impart red color to grape berries (Peppi et al., 2006). Applications of the plant growth regulators (PGRs) gibberellic acid (GA3) and forchlorfenuron (CPPU), which may be needed to increase berry size, can further inhibit coloring. Careful canopy and crop management, and application of ethephon, optimize the color of ‘Crimson Seedless’ grapes (Dokoozlian et al., 1994), but even grapes subjected to these ideal cultural practices may remain poorly colored, especially when grown in regions or seasons with supraoptimal temperatures (Kliewer, 1970, Dokoozlian et al., 1994, Spayd et al., 2002).

In grapes, anthocyanin accumulation begins at veraison, the onset of maturation. This accumulation appears to be regulated, at least in part, by the plant hormone abscisic acid (ABA) (Kataoka et al., 1982, Hiratsuka et al., 2001, Ban et al., 2003), and exogenous applications of ABA increased the anthocyanin content of grape skins (Peppi et al., 2006, Peppi et al., 2007). In general, grapes having high skin anthocyanin content will appear darker and more red-colored, than grapes having low anthocyanin content, but the relationships between pigments and berry color characteristics are non-linear, so relatively large differences in pigment content may have little effect on berry color (Peppi et al., 2006, Peppi et al., 2007). Even so, ABA treatment improved the color of ‘Flame Seedless’ (Peppi et al., 2006) and ‘Redglobe’ grapes (Peppi et al., 2007).

Historically, the cost to produce ABA was too high to justify its use as an agrochemical, but recently ABA production methods have improved sufficiently to reconsider its potential use in viticulture. Furthermore, ABA proved to be more effective than ethephon at improving the color of ‘Crimson Seedless’ table grapes but the most effective treatments sometimes induced berry softening (Peppi, personal communication), an undesirable condition for fresh grapes that might have further implications for their postharvest storage. Table grapes tend to senesce and deteriorate during postharvest handling (storage and marketing) which limits their market life (Crisosto and Mitchell, 2000). Quality deterioration in clusters of grapes is expressed in terms of weight loss, rachis senescence or necrosis, berry shatter, fruit softening, undesirable color changes in the berries or rachis, and the development of fungal rots (Carvajal-Millan et al., 2001, Crisosto et al., 2002). The severity of these quality changes vary according to cultivar, and to practices in the vineyard and in the postharvest storage facility (Carvajal-Millan et al., 2001, Crisosto et al., 2002). Thus, the postharvest quality of ABA-treated grapes should be considered before recommendations on the use of ABA are made. The objective of this study was to determine whether the postharvest quality of grapes treated with different concentrations of ABA differed from that of grapes treated with 250 μL L−1 ethephon, a standard commercial practice, or from grapes not treated with either PGR.

Section snippets

Plant material and PGRs applications

Nine-year-old own-rooted ‘Crimson Seedless’ grapevines (Kearney Agricultural Center, Parlier, CA) of similar capacity and crop load were used in the study. Each vine was trained to quadrilateral cordons, supported by an open gable trellis, and spur-pruned. The vines were spaced 2.4 m within rows and 3.6 m between rows. The vineyard was drip irrigated and standard cultural practices were followed, including berry thinning (2.5 g GA3 per ha at 80% anthesis), girdling for berry sizing (6 mm girdle at

Initial quality

Clusters of grapes attained marketable quality between 22 August and 3 November, depending on the treatments they received. Grapes treated with 300 μL L−1 ABA colored quickly and thus were harvestable about 30 d earlier than untreated grapes, and 10 d earlier than grapes treated with ethephon (Table 1). On average, grapes treated with 150 μL L−1 ABA were harvestable at about the same time as grapes treated with 300 μL L−1 ABA or ethephon, and grapes treated with either 150 μL L−1 ABA or ethephon were

Acknowledgements

The authors acknowledge financial support from the California Table Grape Commission, the California Competitive Grants Program for Research in Viticulture and Enology, and from Valent BioSciences. Ms. Celia M. Cantín was supported by a FPU fellowship from Spanish MEC (Ministerio de Educación y Ciencia). We also acknowledge the assistance of M. Cecilia Peppi, Kimberley Cathline, and Jorge Osorio Aguilar.

References (18)

There are more references available in the full text version of this article.

Cited by (169)

View all citing articles on Scopus
View full text