The Influence of Rootstock on Fruit Ethylene, Respiration, Index of Absorbance Difference, Fruit Quality, and Production of ‘Aztec Fuji’ Apple under a Full-crop Condition

Abstract

Selection of dwarfing rootstocks that facilitate optimum production of high-quality fruit is crucial in modern high-density apple orchards. In addition to tree growth and yield, rootstocks can influence fruit maturity of scion cultivars in apples. In this study, the impact of 17 rootstocks on fruit maturity, yield, and quality attributes of ‘Aztec Fuji’ apples (Malus domestica Borkh.) at harvest were evaluated in a season when all trees were in a “full-crop” condition. Keeping sealed fruit at room temperature, a typical climacteric pattern was observed in ethylene evolution, respiration, and oxygen consumption, peaking after 5–7 days in fruit from trees on all rootstocks. During the ripening period, ethylene evolution and respiration rates in fruit from trees on Supp.3, G.3001, and G.202 were often in the high-range category, whereas those on CG.4004, CG.4214, G.41N, and B.9 were in the midrange category and those on M.9Pajam2, M.26EMLA, and G.11 were in the low-range category. Evolved ethylene and respiration in fruit from trees on M9.T337 steadily and slowly increased from 7 days after harvest (7DAH) to 13 days after which harvest (13DAH) ethylene sharply increased, signaling occurrence of climacteric peak, while respiration declined after the peak of 13DAH. In fruit from trees on most rootstocks, the rates of oxygen consumption had inverse relationships with the rates of respiration, so that fruit from trees on M9.T337 had higher and those on G.41N and Supp.3 had lower rates of oxygen consumption. Trees on G.41N, CG.4004, and M.26EMLA had higher and those on CG.4003 had lower yield per tree than trees on other rootstocks. Trees on B.9 and M.9T337 were most yield efficient among trees on all rootstocks. Trees on CG.4004 had larger fruits than those on other rootstocks. Considering all fruit maturity, quality, and yield attributes, CG.4004 seems to be a good choice of rootstock for ‘Aztec Fuji’ under the conditions of this study.

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

“…On the other hand, changes from green to yellow in the background color of apples, through a decrease in the values of chlorophyll disapearance (I AD ), have been shown to be associated with increased fruit maturity [51]. These results support the significantly negative correlations between I AD and IEC obtained for fruit in all trees on all assessed rootstocks in this work, and is consistent with other studies in apples [55] and peaches [24,51]. Furthermore, in the present study, rootstocks dramatically affected 'Buckeye Gala' fruit red coloration and chlorophyll disappearance, in agreement with other authors using 'Gala' and 'Fuji' as scion cultivars [11,14,32,55].…”

“…In agreement with the latter, our results show a consistent effect of rootstocks on IEC of 'Buckeye Gala' fruit at harvest. Furthermore, the positive correlations of IEC with fruit weight, skin blush and SPI, as well as the negative associations of IEC with flesh firmness, TA, skin and flesh hue angle and index of absorbance difference (I AD ), are in agreement with other studies [24,55] and are indicative of IEC promoting an increase in fruit maturity. The highest IEC values in 'Buckeye Gala' fruit at harvest were associated with fruit from the dwarfing and lower yielding G.11, M9.T337 and G.41 rootstocks.…”

“…Apple fruit display a climacteric fruit ripening behavior; thus, IEC has been reported to play a key role in controlling fruit maturity in apples [21]. Previous results in the influence of rootstock genotypes on IEC are contradictory, as some have found no relationships [6] while others have found significant effects of rootstocks on fruit scion IEC [14,25,26,54,55]. In agreement with the latter, our results show a consistent effect of rootstocks on IEC of 'Buckeye Gala' fruit at harvest.…”

“…Rootstocks are a key component of apple production systems and can significantly influence scion cultivar physiology. Although there are several reports on the effects of rootstocks on apple maturity and quality characteristics [6,14,15,28,[30][31][32][33]40,54,55], the results are inconsistent from site to site and/or for different scion cultivars. Particularly, there is limited information about rootstock effects on maturity and quality of apples grown in Western Maryland.…”

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

“…Additionally, changes from green to yellow in the background color of apples, through a decrease in the values of hue angle as well as a result of chlorophyll disappearance (I AD ), have been shown to be associated with increased fruit maturity [28,48]. These results support the significantly negative correlations between I AD and IEC obtained in this work, and are consistent with other studies in apples [28,42,56] and peaches [45,48]. The significantly highest and lowest hue angle and I AD values for AVG-only-and Extenday-only-treated 'Honeycrisp' apples, respectively, are indicative of the delay and advancement of background color changes, respectively.…”