Assessing Fruit Maturity and Quality of ‘Buckeye Gala’ Grown on a Diverse Panel of Apple (Malus domestica Borkh.) Rootstocks in Western Maryland

Abstract

Apple (Malus domestica Borkh.) is usually produced in the form of a rootstock grafted scion. Rootstocks have important effects on several horticultural attributes. However, the results are not consistent regarding sites and scion–rootstock combinations. The aim of this research was to characterize the horticultural performance of ‘Buckeye Gala’ apple scion grafted onto ten rootstocks grown in Western Maryland during two harvest seasons. Our results demonstrated that, on average, tree size and yield in G.935, M.26 and G.969 rootstocks were 5–40% higher, but weight per fruit was 2–15% lower than in all other rootstocks. Fruit maturity was significantly delayed with increasingly vigorous rootstocks. There were no crop load differences. Overall, the assessed rootstocks were discriminated into seven significantly distinct clusters characterized by marked differences in vigor, yield, and fruit maturity. Moreover, significant correlations were obtained amongst all assessed variables. Rootstock impact must be considered when making management decisions in ‘Buckeye Gala’ fruit grown under Western Maryland conditions as they are critical in modulating fruit maturity and quality.

Combining the Use of Reflective Groundcovers and Aminoethoxyvinylglycine to Assess Effects on Skin Color, Preharvest Drop, and Quality of ‘Honeycrisp’ Apples in the Mid-Atlantic US

“…The internal ethylene concentration (IEC) of each fruit was measured on 1 mL samples of internal gas from the core cavity using a gas chromatograph (GC-2014C, Shimadzu Co., Kyoto, Japan) equipped with an activated alumina column attached to a flame ionization detector as previously described [28,45,46]. Nitrogen (N 2 ) was used as the carrier gas at a flow rate of 30 mL min −1 , while O 2 and H 2 were used to create the flame of the detector at a flow rate of 300 and 30 mL min −1 , respectively.…”

“…Fruit quality is determined by multiple irreversible physiological and biochemical modifications that take place as fruit matures [26]. These include modifications in fruit skin color (background and red surface color), texture (flesh softening), and flavor (increase in sugar contents, decrease in organic acids, and changes in aroma volatiles) [27][28][29]. In addition, regarding preharvest fruit drop, ethylene can promote the degradation of the cell wall and intercellular tissues in the abscission zone of the pedicel, resulting in fruit drop [30,31].…”

The Expression of Key Ethylene and Anthocyanin Biosynthetic Genes of ‘Honeycrisp’ Apples Subjected to the Combined Use of Reflective Groundcovers and Aminoethoxyvinylglycine in the Mid-Atlantic US

“…The fruit internal ethylene concentration (IEC) was measured using 1 mL samples of internal gas from the core cavity of each fruit using a gas chromatograph (GC-2014C, Shimadzu Co., Kyoto, Japan), as described before [ 4 , 50 , 82 ]. The apple fruit red skin coloration was assessed as previously described [ 4 , 50 , 83 ].…”

“…Previous studies have shown that the initiation of anthocyanin biosynthesis and ethylene production concur [ 48 ]. However, ethylene production can also enhance fruit ripening, therefore directly impacting the fruit quality [ 4 , 49 , 50 , 51 , 52 , 53 ], and, at the same time, can promote the apple preharvest fruit drop [ 54 ]. The biosynthesis of ethylene has been significantly studied in fruit that present a climacteric behavior, such as apples, which display a rise in their rate of respiration and the internal ethylene concentration (IEC) as the ripening progresses [ 50 , 55 , 56 ].…”

“…However, ethylene production can also enhance fruit ripening, therefore directly impacting the fruit quality [ 4 , 49 , 50 , 51 , 52 , 53 ], and, at the same time, can promote the apple preharvest fruit drop [ 54 ]. The biosynthesis of ethylene has been significantly studied in fruit that present a climacteric behavior, such as apples, which display a rise in their rate of respiration and the internal ethylene concentration (IEC) as the ripening progresses [ 50 , 55 , 56 ]. Ethylene biosynthesis is driven by 1-aminocyclopropane-1-carboxylate synthase (ACS), which converts S-adenosyl-L-methionine (SAM) to 1-aminocyclopropane-1-carboxylate (ACC), and subsequently, by the action of ACC oxidase (ACO), drives the oxidation of ACC to ethylene [ 57 , 58 ].…”