locations in Chile. Materials and Methods Plant material. A set of seven apple ( Malus ×domestica Borkh.) cultivars (‘Galaxy’, ‘Brookfield ® Gala’, ‘Super Chief’, ‘Fuji Raku Raku’, ‘Braeburn’, ‘Granny Smith’, and ‘Cripp's Pink’) grafted on two virus
Jose A. Yuri, Claudia Moggia, Carolina A. Torres, Alvaro Sepulveda, Valeria Lepe, and Jose L. Vasquez
Nobuko Sugimoto and Randy Beaudry
The objective of the experiment was to determine developmental changes in major aroma profiles in `Jonagold' apple (Malus ×domestica Borkh.) and analyze climacteric fruit characteristics. Changes in internal ethylene production, respiration, skin color, texture, and aroma concentration were measured during maturation and ripening of `Jonagold' apple fruit. Patterns for skin color, starch, and internal ethylene content were typical for the variety. Volatile compounds and CO2 increased after a rapid increase in ethylene production. Total ester emission peak coincided with fruit softening. Hexyl acetate, 2-methylbutyl acetate, butyl acetate, and hexyl 2-methylbutanoate were found to be the major volatile compounds detected by GC/MS. Long chain esters, such as hexyl acetate and butyl acetate, contributed during the early stages of ripening and short chain esters such as n-propyl acetate and butyl propanoate increased later. Esters are formed by combining alcohol moiety with CoA derivative of fatty acid moiety by the action of alcohol acyl transferase (AAT). The alcohols butanol, 2-methylbutanol, propanol, and hexanol increased at an earlier developmental stage than the esters for which they acted as substrates.
Fenton E. Larsen and Stewart S. Higgins
Tree size, cumulative yield, yield efficiency and anchorage of 6 micropropagated (MP) apple (Malus domestica Borkh.) cultivars were determined in 1991 after 5 years of production, as compared with trees on seedling (sdlg) or M 7a roots. Trees were planted in 1984, with crops harvested from 1987 through 1991. Trees were generally smallest (trunk cross-sectional area) on M 7a and were largest with 4 cultivars (`Delicious', `Jonathan', `Rome', `Spartan') when micropropagated. `Golden Delicious' (GD) was largest on sdlg. Cumulative yield was affected by a scion × rootstock interaction, with few trends in scion or rootstock effects. Mean cumulative yield was 84 kg tree-1, 71 and 58 for M 7a, MP and sdlg, respectively. Yield efficiency was also affected by a scion × rootstock interaction. In 1991, mean yield efficiency was 0.5 kg cm-2 for sdlg and MP trees, but was 1.05 for M 7a. Efficiency on M 7a was superior to other rootstocks with all scions except `GD', while sdlg and MP trees were statistically similar with all scions. All trees leaned in response to prevailing westerly winds, with trees on sdlg tending to be more upright than MP or M 7a trees.
Jan Bizjak, Nika Weber, Maja Mikulic-Petkovsek, Ana Slatnar, Franci Stampar, Zobayer Alam, Karl Stich, Heidi Halbwirth, and Robert Veberic
mechanism, by which P-containing compounds affect the red coloration of apples. Materials and Methods Plant materials. The experiment was carried out in 2011 on 10-year-old trees of striped ‘Braeburn’ ( Malus domestica Borkh.) cultivar clone Hillwell
Carole L. Bassett, D. Michael Glenn, Philip L. Forsline, Michael E. Wisniewski, and Robert E. Farrell Jr
then by humans over the silk road trade routes into Europe. The modern cultivated apple ( Malus × domestica Borkh.) is believed to have been domesticated in Turkestan, now Kazakhstan, Kyrgyzstan, Uzbekistan, Turkmenistan, and Tajikistan ( Harris et al
M.E. Garcia and Linda A. Boccuzzo
Hardiness testing of the wood of deciduous fruit trees has been conducted using a variety of techniques. In our studies, the objective was to determine an efficient method of determining freezing injury for apple (Malus × domestica Borkh.) wood. We tested 1-year old wood of two cultivars: Liberty and RedMax. The wood was tested over the course of 2 years (1998 and 1999). Collection began in the late fall and continued throughout the winter (until it was determined full hardiness had been achieved) and then again in the early spring. The wood was cut into 1-cm sections and frozen. The artificial freezing was conducted in an ethanol bath, with the temperature lowered at 5 °C/h. Samples were removed in 3-min intervals. After freezing, the wood was acclimated to 4 °C for 12 h. Three tests were conducted to determine the hardiness/injury to the tissues. The tests used were: discoloration, callus growth and vital staining (with 2,3,5-triphenyltetrazolium chloride). This was a split block design with samples collected randomly from each tree. Four replicates (12 trees) of each cultivar were tested. Results showed that the callus test predicted the same LT50 as the other two tests, discoloration and vital staining. Discoloration was not easy to differentiate and was the most time-consuming. The callus grown by the apple wood was easily formed and distinguished. The callus test does not require the tetrazolium stain; therefore, one less step was needed in comparison to the vital staining test. This reduced testing time by over 6 h.
Travis Robert Alexander, Jacqueline King, Andrew Zimmerman, and Carol A. Miles
Cider is fermented apple ( Malus ×domestica Borkh.) juice, and is often referred to as hard cider in the United States in contrast to the nonfermented, unfiltered apple juice that is referred to as fresh cider or sweet cider ( Khanizadeh et al
Shiow Y. Wang, Miklos Faust, and Michael J. Line
The effect of Indole-3-acetic acid (IAA) on apical dominance in apple (Malus domestica Borkh.) buds was examined by studying changes In proton density (free water) and membrane lipid composition in lateral buds. Decapitation induced budbreak and enhanced lateral bud growth. IAA replaced apical control of lateral bud paradormancy. Maximal inhibition was obtained when IAA was applied immediately after the apical bud was removed. Delaying this application weakens the effect of IAA. An increase in proton density in lateral buds was observable 2 days after decapitation, whereas the change in membrane lipid composition occurred 4 days later. Decapitating the terminal bud induced an increase in membrane galacto- and phospholipids. and the ratio of unsaturated to corresponding saturated fatty acids. Decapitation also induced a decrease in the ratio of free sterols to phospholipids in lateral buds. Application of IAA to the terminal end of decapitated shoots inhibited the increase of proton density and prevented changes in the membrane lipid composition of lateral buds.
Edwin J. Reidel*, Brian G. Ayre, E. Robert Turgeon, and Lailiang Cheng
Sorbitol (d-glucitol) is the major end product of photosynthesis in apple (Malus domestica Borkh.), as well as the predominant phloem-translocated carbohydrate. The mechanism by which sorbitol is phloem-loaded for transport to heterotrophic sink tissues is unknown. We hypothesized that a plasma membrane-bound H+/sorbitol symporter mediates apoplastic phloem-loading of sorbitol. To discover genes potentially encoding sorbitol transporters, a cDNA library was constructed from mature `Gala' apple leaves. A homologous probe was synthesized via PCR with primers were designed against the cherry fruit sorbitol transporter, PcSot1, and using library lysate as template. From an initial plating of approximately 5 × 105 clones, twelve positives were identified after three rounds of hybridization screening. Following single-pass, 5' end sequencing, the clones were sorted into four contiguous sequences. One clone was chosen from each contig for complete sequencing. The four clones, provisionally named MdSOT1-4 (Malus domesitca Sorbitol Transporter), potentially encode full-length cDNAs for sorbitol transporters: Translated-BLAST searching (blastx) revealed that the open reading frames encode the complete Pfam sugar transporter domain, and the most significant alignments are with sequences encoding known- and putative polyol and sugar transporters.
Q. Liu, S. Salih, J. Ingersoll, R. Meng, L. Owens, and F. Hammerschlag
Transgenic `Royal Gala' apple (Malus × domestica Borkh.) shoots were obtained by Agrobacterium-mediated gene transfer using the plasmid binary vector pGV-osm-AC with a T-DNA encoding a chimeric gene consisting of a secretory sequence from barley-amylase joined to the modified cecropin MB39 coding sequence. Shoots were placed under the control of a wound-inducible, osmotin promoter from tobacco. The integration of the cecropin MB39 gene into apple was confirmed by Southern blot analysis. The transformation efficiency was 1.5% when internodes from etiolated shoots were used as explants and 2% when leaf explants were used. Both non- and transgenic tetraploid plants were produced by treatment of leaf explants with colchicine at 25 mg·L-1, and polyploidy was confirmed by flow cytometry. Of the diploid transgenics, three of seven were significantly more resistant to Erwinia amylovora than the non-transgenic `Royal Gala' control. Also, in one instance, a tetraploid transgenic was significantly more resistant than the diploid shoot from which it was derived.