Abnormal auxin distribution and poor berry setting (coulure) in grapes

A constant low auxin level was observed in a normally setting trimmed cluster of the tetraploid grape ‘Kyoho’ (Vitis vinifera L. × Vitis labrusca L.). The basipetal auxin transport in the trimmed cluster was always 2–3 times higher than the acropetal transport during the flowering-period. In a non-treated cluster, showing a tendency towards excessive berry abscission, the auxin level in the apical parts of the cluster fluctuated within the range of 20–70 times that of the auxin content at full bloom. The ratio of basipetal to acropetal auxin transport was nearly unity or less than unity.The results support the hypothesis of apical dominance and auxin gradient in the formation of an abscission zone.     

Manual and chemical induction of side-shoot formation in apple trees in the nursery

An experiment was set up to find a manual method for side-shoot formation as an alternative to the use of chemicals. On growing buds of 2 apple cultivars — budded August 1976 on M.9 rootstock — which often do not form laterals in the nursery (‘Red Boskoop’ and ‘Benoni’), the following treatments were carried out in the summer of 1977: decapitation (removal of the growing-point plus all young leaves); removal of the young leaves, leaving only the actual growing-point intact; spraying with 0.176% FR $\text{570}\text{3}$ (containing 0.15% May and Baker 25 105). All these treatments were applied at about 55 cm shoot length. In a separate series, the young-leaf removal was repeated at about 65–75 cm shoot length. Untreated trees served as controls.All treatments stimulated side-shoot formation; M&B 25 105 most of all. The manual treatments gave similar results with respect to total shoot number but not to height and orientation of the laterals or the vigour gradient along the stem. From the point of view of suitability of the side shoots (i.e. sufficient height above the soil and a large crotch angle), only the chemical treatment and the once-repeated removal of young leaves proved satisfactory. The latter method may offer an alternative to the use of chemical branching-agents.The results are discussed in relation to studies on apical dominance.     

Yield benefits associated with pre-blossom low-biuret urea sprays on Citrus spp.

Summary

This study evaluated the potential yield benefits of pre-blossom urea sprays on various Citrus spp. and to ascertain whether these yield benefits are as a result of altering the blossom composition or of supplying readily utilizable N during the critical flowering/fruit set period. Pre-blossom low-biuret urea sprays, 6–8 weeks before anthesis, at 1% concentration, one or two sprays 10–14 d apart, have resulted in significant (P<0.05) yield benefits in certain orchards. Experiments were conducted over a period of 2–4 years. Cultivars evaluated included ‘Shamouti’ oranges, ‘Ellendale’ tangor and ‘Minneola’ tángelo. In orchards where the leaf N level was below optimum the results were most significant while only slight or no yield responses were obtained in orchards where N levels approximated or exceeded 2.6%. Endogenous leaf ammonia levels were significantly increased for 14–30 d after the spray. This indicated a beneficial N level during the critical flowering and fruit set period. Because of large field variation no consistent trend with respect to the effect of the urea spray on changing the blossom composition (leafless vs. leafy inflorescences) could be demonstrated. Despite the increased ammonia levels recorded, no longer term increases in reserve leaf N levels were obtained.     

A comparison of high- and low-volume spray techniques in the thinning of ‘Golden Delicious’ apples

A trial at the Grove Research Station, southern Tasmania in 1989-90 examined the thinning of mature ‘Golden Delicious’ apple trees. High-volume sprays were applied at 6,0001 ha^-1 as air blast or vertical boom using NAA at 10mg l^-1 4d after full bloom (AFB) and 18 d AFB. Carbaryl at 1,000 mg l^-1 and thiram at 1200 mg l^-1 were also applied as combined sprays, 30 and 38 d AFB. These high-volume sprays were compared with unsprayed controls and Micron and Micronair low volume sprayers at 200 and 1,1000 l ha^-1. The dosages of the low volume applications were equilibrated to apply the same rates of chemical per hectare as the high-volume sprays, and the timing was the same. All spray treatments reduced crop load to acceptable levels when compared with the overcropped controls. There were no consistent differences between treatments for number of fruit per cm² limb area except that the lowest volume Micron spray thinned significantly less than most other treatments. Considering the number of fruit per 100 blossom clusters the airblast spray was the only treatment to be significantly better than the Micron at 2001 ha^-1. These numbers were reflected in mean fruit weight with the control fruit being significantly lighter than any sprayed fruit. The air blast treatment produced significantly heavier fruit than all other treatments, apart from the other high volume treatment. Fruit size distribution (FSD) showed significant differences between the control and all the spray treatments. The airblast treatment produced significantly more fruit in the 80 mm or larger category than all treatments, apart from the vertical boom application. These preliminary results suggest that although low-volume sprays can thin apple trees, the use of ultra low volumes (ULV) should be explored using machines capable of controlled droplet application (CDA). This may ultimately lead to less chemical being applied per hectare.     

Effects of light quality on shoot proliferation of Prunus cerasifera in vitro are the result of differential effects on bud induction and apical dominance

Summary

The morphogenic effect of different light qualities was investigated on in vitro shoot proliferation of Prunus cerasifera (clone Mr.S. 2/5) in relation to apical dominance and node formation. In intact microcuttings, leader stem length was not affected by light quality but blue and white light produced a higher number of nodes, with shorter internodes than red or far-red light or darkness. The proportion of nodes producing outgrowing lateral shoots was higher in red and far-red light than in white, blue or darkness. In decapitated microcuttings apical dominance was fully released in all the light treatments but not in darkness. Taken together the data show that the proliferation rate is a product of bud induction and release from apical dominance which are differentially affected by light quality. The much lower percentage outgrowth in white and blue light as compared with red light indicates a specific effect of blue light acting in the opposite direction to active (far-red light absorbing) form of phytochrome on apical dominance.     

1-Naphthaleneacetic acid and 6-benzyladenine thinning of a common slender spindle ‘Jonagold’/M.9 apple orchard. I: Dose effects and spray distribution in the crowns

Summary

To find the most appropriate rates of application of plant growth regulator (PGR) thinning-agents for a common slender spindle apple (Malus × domestica Borkh.) orchard, different volumes of dilute 1-naphthaleneacetic acid (NAA) and 6-benzyladenine (BA) were sprayed ha^?1. Mature ‘Jonagold’/M.9 trees, 3.0 – 3.5 m high and 1.2 – 1.5 m wide, planted in a single row system with 3,030 trees ha^?1, were used. Significant thinning was observed in the case of dilute sprays of NAA at 10 mg l^?1, or BA at 100 mg l^?1, to run-off, using 2,000 l ha^?1 or 1,500 l ha^?1; while 1,000 l ha^?1 did not result in sufficient thinning. Thinning using smaller volumes (250, 500, or 750 l ha^?1) was also significant if the concentration of PGR thinner was proportionally higher (i.e., based on the 1,500 l ha^?1 application rate of more dilute sprays of NAA at 10 mg l^?1 or BA at 100 mg l^?1). Spray distribution measurements in the crowns showed better spray deposits when higher water volumes (i.e., more dilute PGR solutions) were sprayed at all positions (bottom, middle, or top) of the canopy. At 2,000 l ha^?1, 54 – 72% coverage of the leaf area was observed; but, at 250 l ha^?1, coverage was only 10 – 21%. The lower 30% of the canopy was covered poorly when smaller volumes of water (250, 500, or 1,000 l ha^?1) were applied. When 1,500 l ha^?1 was sprayed, good coverage of the lower and upper surfaces of the leaves occurred, and no differences in canopy positions were measured. It was concluded that 1,500 l ha^?1 (i.e., dilute PGR) spraying was the most appropriate volume to use when calculating the dose of NAA or BA to be applied ha^?1 to common (3.0 – 3.5 m-high) mature slender spindle apple orchards on M.9 rootstock. This study was part of the ISAFRUIT Smartfruit Project, aimed at improving existing methods for apple crop regulation with more precise use of PGR thinning agents and with minimum impact on the environment.     

The Response of Magnesium-Deficient Edward VII Apple Trees to Variations in the Timing and Composition of Foliar Sprays

Magnesium-deficient Edward VII apple trees were used to study the effect of pre-blossom sprays of magnesium sulphate and urea, and to compare the efficiency of post-blossom sprays of magnesium sulphate and chloride.

Two pre-blossom sprays of 2% Epsom salt (MgSO_4·7H,O) prevented the development of early-season magnesium deficiency symptoms but did not increase fruit set. Similar sprays of 0· 5%urea had no effect on symptoms but increased the set of fruit.

Five post-blossom sprays of 2% Epsom salt largely eliminated both early and late symptoms and produced consistent increases in the magnesium content of the leaves (% dry wt.). There was also a large increase in crop, due mainly to a greater fruit set which could be detected after the second spray application. Growth responses also were associated with this treatment.

Five post-blossom sprays of 0·83% magnesium chloride, i.e. containing only half the amount of magnesium, produced similar responses, except that growth was not affected. Reducing the number of magnesium chloride sprays to three, but applying them over the same time interval, resulted in similar' crop responses even though less magnesium was taken up and symptoms were slightly less effectively controlled.     

Spatial distribution of Malus root systems in irrigated,trellised orchards

Summary

Root distribution was determined for apple trees [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. ‘Fuji’/’M.26’ (syn. M. domestica Borkh. non Poir.)] 1, 2 and 3 years after planting in trellised orchards in central Texas. Using a soil-coring method, measurable differences were detected in root-length density (RLD; root length per unit volume of soil) by tree age, soil depth, radial distance from the tree, and spatial bearing within and across rows (P ≤ 0.05). For fine roots (root diameters < 1 mm), mean RLD values were 0.1028, 0.1139 and 0.2911 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. For coarse roots (root diameters 1–5 mm), mean RLD values were 0.0006, 0.0009 and 0.0015 cm cm^–3 for 1, 2 and 3 year-old plantings, respectively. Mean RLD values declined for both fine and coarse roots of all ages with increasing soil depth and radial distance from the trunk (P ≤ 0.05). Similar patterns were observed for the number of soil cores containing measurable roots. The percentage of samples with no roots increased with increasing soil depth and distance from the trunk (P ≤ 0.05). When examining fine roots by spatial bearing from the tree, the greatest RLD was found along the drip irrigation lines for the two youngest plantings and along drip irrigation lines and beneath shaded trellises for the oldest planting (P ≤ 0.05). For coarse roots, the greatest RLD was found along the drip irrigation lines for all plantings (P ≤ 0.05). This information is important for predicting the rates and locations of new root growth in orchards after transplanting, so that management techniques (e.g., fertilisation, irrigation, control of soilborne diseases) can be properly targeted and effectively implemented.     

Use of 6-benzylamino purine and Promalin for improved canopy development in selected apple cultivars

Foliar sprays of Promalin (gibberellins A_{4 + 7} + 6-benzylamino purine) applied to 1-year-old apple (Malus domestica Borkh.) trees at the 3–5-cm growth stage significantly increased lateral branching in 5 of 9 cultivars tested. Branching response ranged from 0% (‘Winter Banana’) to 131% (‘Starkrimson Delicious’) of the untreated controls. Total shoot growth was not consistently increased by 6-benzylamino purine or Promalin in tests over 3 years on spur and non-spur 1- and 2-year-old apple trees. Sprays of 50–300 mg l⁻¹ Promalin were ineffective for increased branch development. Sprays of 300–500 mg l⁻¹ increased total shoot numbers and reduced average shoot length. Sprays applied prior to new terminal growth in spring were ineffective. Treatment during periods of active shoot growth were generally effective, but periods of stress may have reduced response. Sprays were more effective for inducing lateral shoot formation than dormant heading or delayed dormant heading (pruning) (10 days after full bloom) in ‘Criterion Golden Delicious’. No difference in branching response was observed between BA and Promalin. Addition of a spray adjuvant (Buffer-X) did not affect branching response. Repeat annual single sprays of Promalin applied to dormant pruned trees were generally less effective for stimulating lateral branching than a single application in a given year. Phytotoxicity was associated with Promalin sprays at 300–500 mg l⁻¹ on ‘Delicious’.     

Corm induction and multiplication of Amorphophallus albus in vitro

Summary

Amorphophallus albus, belonging to the family Araceae, has attracted widespread attention due to its considerable economic and medicinal importance. The natural propagation coefficient of A. albus is very low, which limits application of this crop. In vitro corms can be used for propagation of A. albus and have been proved to be superior over in vitro plantlets. To optimise procedures for in vitro corm production and multiplication, the effects of phytohormones, sucrose concentrations and incubation conditions with desirable phytohormone combinations for callus induction, corm formation and corm growth of A. albus were investigated. The results showed that calli were induced at high frequency from petiole segments on Murashige and Skoog medium supplemented with 1.0 mg l^–1 naphthaleneacetic acid (NAA) and 1.0 mg l^–1 6-benzyladenine (BA). Compact nodular calli were desirable for corm formation, and optimum corm formation was obtained in the presence of 0.5 mg l^–1 NAA and 2.0 mg l^–1 BA. With this auxin and cytokinin combination, an increase in sucrose concentration from 2% to 6% (w/v) significantly increased the corm formation rate and favoured corm growth, but negative effects occurred at higher sucrose concentrations. By incubating over a range of temperatures from 19°C – 28°C, 22°C produced the largest numbers of corms and highest mean fresh weight of each corm. Short-day (8 h) or long-day (16 h) photoperiods did not affect corm formation and growth significantly, except that corm weight fell under long-day conditions. The multiplication rate of in vitro corms was enhanced by apical meristem wounding. It was possible to store in vitro produced corms at 4°C for as long as 90 d to overcome apical dormancy and accelerate sprouting after planting into soil. This work has established an efficient protocol for multiplication of A. albus through an in vitro corm system.     

Foliar application of calcium plus boron reduces the incidence of sunburn in ‘Golden Delicious’ apple

Summary

Losses of apple fruit due to sunburn damage under South African climatic conditions can reach up to 40% per annum for specific cultivars in certain years. Various approaches to reduce the incidence and severity of sunburn resulted in temporary effects but, at present, no single remedy is available to provide a significant and consistent reduction in sunburn damage on a commercial scale. ‘Golden Delicious’ apple trees that received both calcium (Ca) and boron (B) as foliar applications on a weekly basis, when applied from approx. 21 – 70 d after full bloom (DAFB), showed significantly less sunburn in two consecutive seasons (P = 0.0500 and P = 0.0247 respectively) than untreated control fruit, or treatments based on Ca alone. The minerals were applied as supplements of sugar-alcohol complexed with Ca and B, trading as Manni-Plex^® Ca [10% (w/w) Ca] and Manni-Plex^® B [3.3% (w/w) B], respectively. The mode of action by which the incidence of sunburn was reduced using combined sprays of Manni-Plex^® Ca plus Manni-Plex^® B remains to be elucidated.     

Vascular blockage in cut roses in a suspension of Pseudomonas fluorescens

Summary

To analyse quantitatively the relationships between cut rose (Rosa hybrida L. ‘Pascha’) vase-life, the onset of cavitation, plant water potential, and bacterial concentrations in the vase water, rose stems were placed in water containing different concentrations of Pseudomonas fluorescens 2892 tet^r rif ^r. There was a significant correlation (P = 0.0009) between cut rose vase-life and the concentration of bacteria in the vase water. As the number of bacteria in the vase water increased, the rate of senescence also increased. The water potential for roses in the bacterial suspension (at 8.50 log₁₀ CFU ml^–1) proceeded to drop constantly after 5.17 h in the vase solution, with the water potential falling to as low as -2.35 MPa by the end of the experiment (at 117 h). In contrast, the water potential of roses in deionised water dropped from -0.419 MPa at 5.17 h, to only –0.663 MPa after 117 h. When roses were stood in a bacterial suspension (at 8.5 log₁₀ CFU ml^–1) for 30 h, 63.8% of the total cumulative cavitation events were seen, while roses stood in deionised water exhibited only 26.8% of the total cavitation events. Uptake of acid fuchsin and the movement of tagged P. fluorescens 2892 in the xylem indicated that bacteria did not travel beyond the open-ended xylem vessels and were generally restricted to the first 50 mm from the cut end of the stem.     

Growth and yield of bean plants as affected by 2, 4-D-micronutrient sprays

Aqueous sprays containing either (1) micronutrients (Fe, Mn, Cu, Zn, B) at a concentration of 5 × 10⁴M, (2) 2, 4-D at 1 ppm or (3) the micronutrients and 2, 4-D together were applied to 2-week-old plants of green bush bean, Phaseolus vulgaris. Measurements of juvenile growth were made 5, 10 and 15 days after treatment; of green pod yield and ascorbic acid content 6 weeks after treatment; and of seed yield when the plants were 13 weeks old. The use of 2, 4-D and of the 2, 4-D-micronutrient sprays resulted in significant (P = 0.05) increases in stem height, leaf number and area, and fresh and dry weights of roots, stems and leaves at all three times of harvest. The yield of green pods, in terms of number and fresh weight per plant, and the pod vitamin C content at harvest and after 4 days’ storage were significantly larger in the treated plants. In all cases the greatest stimulation resulted from the use of the solution containing both the 2, 4-D and microelements. Application of the solution containing only microelements produced values which did not differ significantly from those of control plants.     

Field spray trials for control of the strawberry mite,Tarsonemus fragariae (Zimm.)

Results are given of field trials in which various chemical sprays were tested for control of the strawberry mite Tarsonemus fragariae. Activity of most compounds was poor, although promising results were obtained with Bayer 5024 (methiocarb), Boots BTS 27419, Du Pont 1642 and Shell WL 21959 (‘Talcord’). None gave as good control as a standard endosulfan spray, but some results were better than those achieved with a standard application of dicofol.     

The effects of Apogee® on shoot growth,secondary flowering,fire blight,fruit quality,yield and return bloom in ‘Bartlett’ pear growing in California

Summary

Apogee^® sprays were applied to mature ‘Bartlett’ pear (Pyrus communis L.) trees as single or multiple sprays during the growing seasons of 1999 to 2003 at concentrations of 420 g ha^–1 (125 mg ^–1) or 840 g ha^–1 (250 mg^–1): both reduced vegetative shoot growth. Two sprays of 840 g ha^–1 applied 3–3.5 weeks apart were most effective and reduced shoot growth by approximately 40%. An application made 2 d after fall bloom was ineffective and led to more vegetative shoot growth. Single sprays of Apogee^® made within 9–28 d after full bloom (DAFB) were equally effective in reducing vegetative shoot growth. Bourse shoot growth was reduced 43% by 3 April, 2001 (8 DAFB) treatment of 840 g ha^–1 when bourse and vegetative shoots ranged from 2.5 to 7.5 cm in length. Subsequent single applications of 840 g ha^–1 Apogee^® (on April 12 or 23, 2001) did not reduce bourse shoot growth significantly. Vegetative shoot growth was also reduced by 12% (9 d after treatment) and by 38% (approximately one month after treatment) by 840 g ha^–1 Apogee^® applied on 3 April, 2001, (8 DAFB). In 2002, bourse shoot growth was controlled most effectively by split applications (840 + 420 g ha^–1 or 840 2 g ha^–1, 9 April and 24 May) and by 840 g ha^–1 Apogee^®, applied at 2.5 to 7.5 cm shoot growth (9 April). These split applications, as well as girdling, decreased shoot strikes in 2002, the year after treatment. Split applications of 840 g ha^–1 Apogee^® made in April to early May were most effective in controlling both vegetative and bourse shoot growth in most years, although single applications of Apogee^® were effective in some years. Subsequent flushes of shoots tended to be controlled by split applications with the second application timed to the emergence of new shoots. Apogee^® was not consistently effective in reducing the incidence of Type I or Type V secondary flowers in these trials. Single or multiple sprays of Apogee^® had no measurable or consistent effect on return bloom, fruit size or shape, firmness, percentage soluble solids, or yield per tree over the period of these experiments. Apogee^® appears to have promise as a shoot growth control agent in ‘Bartlett’ pear growing in California, USA, without deleterious effects.     

Effect of GA3, Planofix (NAA) and Ethrel on granulation and fruit quality in ‘Kaula’ mandarin

The effect of GA₃ 15 mg l^?1, Planofix (NAA = 1-naphthalene acetic acid) 300 mg l^?1 and Ethrel 250 mg l^?1 on granulation and fruit quality in ‘Kaula’ mandarin (Citrus recticulata Blanco) was studied during 1975–1976. Three sprays of Planofix reduced the incidence of granulation to 30.7% from 62.7% in control. Three sprays of GA₃ were almost equally effective (31.3% granulation). These treatments also improved the fruit quality and gave the highest fruit weight, pulp percentage, juice, T.S.S., reducing and non-reducing sugars and ascorbic acid, and the lowest acidity, peel and rag. In both these treatments (3 sprays of GA₃ or Planofix) the T.S.S. was 9.3% (8.1% in control). The application of 3 sprays of Planofix 300 mg l^?1 or GA₃ 15 mg l^?1 is, therefore, considered to be successful in reducing the granulation in this cultivar of mandarin.     

1-Naphthaleneacetic acid and 6-benzyladenine thinning of a common slender spindle ‘Jonagold’/M.9 apple orchard. II: Partial tree spraying

Summary

Mature slender spindle ‘Jonagold’/M.9 apple (Malus × domestica Borkh.) trees were thinned using 10 mg l^–1 1-naphthaleneacetic acid (NAA) or 100 mg l^?1 6-benzyladenine (BA) and an axial fan sprayer at a spray volume of 1,500 l ha^?1 applied to the whole canopy, or with smaller volumes, where only the upper half of each canopy was sprayed. Partial spray applications of NAA or BA (at 1,000 l ha^?1, 750 l ha^?1, or 500 l ha^?1) to the upper half of the trees did not cause any reduction in final fruit numbers on the upper half, or on the lower half of each tree. When the whole tree was sprayed to run-off with the same thinning agent, or at 1,500 l ha^?1, successful thinning on both the upper and lower parts of the canopy occurred. Good spray coverage (from 51% to 77%) was also observed on leaves at all canopy positions measured, when whole trees were sprayed at 1,500 l ha^?1.The development of an innovative crop load regulation strategy was an objective of the ISAFRUIT Smartfruit Project.     

Effect of gibberellic acid (GA3) on elongation and rooting of ‘St. Julien A’ rootstock in vitro

‘St. Julien A’ (Prunus instititia L.) rootstock was induced to proliferate shoots on a modified half-strength Murashige and Skoog (MS) medium. Cultures treated with 12.5 mg l^?1 gibberellic acid (GA₃) produced elongated shoots suitable for rooting. Elongated shoots were placed in media with indolebutyric acid (IBA) or indole-3-acetic acid (IAA) with or without a 16-day dark incubation. Light (16-h photoperiod) inhibited rooting. IAA (4 mg l^?1) was ineffective in promoting rooting. Rooting was best when shoots were incubated in the dark with IBA (4 mg l^?1). GA₃ was deleterious to shoots, causing chlorosis and apical die-back. Light regime interacted with auxin treatments in affecting shoot condition. Shoot condition was better on shoots treated with IBA and dark-incubated; while those treated with IAA were better when light-incubated.     

Apical Dominance and Flower Initiation in the Rose

The initiation of leaves and flowers by selected axillary buds of the glasshouse rose cultivar Sonia (syn. Sweet Promise) has been studied both while their extension growth was inhibited by apical dominance and after the inhibition had been removed at one of two times (“early” or “late”). Leaf initiation occurred during growth inhibition so that leaf primordia accumulated in the axillary buds. Flower initiation began, with both treatment times, only after removing apical dominance. Although the total number of leaf primordia formed before the flower was greater in plants of the “late” treatment, the axillary shoots produced in both treatments had similar numbers of leaves with expanded leaflets. Thus many leaf primordia of the “late” treatment plants became scales. The evidence suggests that flower initiation cannot begin while an axillary bud is subject to apical dominance, and that after its removal another factor results in the production of shoots with a relatively constant number of leaves with expanded leaflets.     

Evaluating the effectiveness of different strategies for calcium application on the accumulation of calcium in apple (Malus × domestica Borkh. ‘Braeburn’) fruit

Summary

Orchards displaying calcium (Ca) deficiency are a common phenomenon worldwide, despite the presence of sufficient Ca in the soil and the plant. A 3-year trial was conducted between the 2007 – 2008 and 2009 – 2010 growing seasons to evaluate the contributions of soil and foliar Ca applications to Ca concentrations in ‘Braeburn’ apple (Malus × domestica Borkh.) fruit. Ca(NO₃)₂ (Calflo; Yara Africa, Fourways North, South Africa) was applied as six separate foliar sprays until run-off. Applications were made at 1-week intervals between approx. 21 – 70 d after full bloom (DAFB) at 6.75 ml l^–1. Soil applications of Ca (Tropicote^TM; International ASA, Oslo, Norway) at 300 kg ha^–1 were applied at fruit set, or after harvest, according to standard practice. Mineral analysis was conducted to assess the soluble Ca concentrations of whole fruit (without pips and stalks), to quantify the contribution of foliar sprays or soil-applied Ca. Fruit Ca concentrations were maintained at satisfactory levels (4.5 mg Ca 100 g^–1 FW) at harvest by applying a series of six foliar sprays early in the season (for all seasons) during the trial period. Fruit Ca concentrations at 80 DAFB were highest in the treatments with foliar applications of Ca. In 2009 – 2010, Ca concentrations in apple fruit were lowest (8.38 mg 100 g^–1 FW) for soil application of Ca at fruit set. Ca applications to soil after harvest in the previous season, and soil applications shortly after fruit set in the current season, did not significantly increase Ca concentrations in current-season fruit, providing soil Ca levels were above the minimum requirement for apple trees. A possible explanation is that apple trees regulate their uptake of Ca through the roots when soil Ca is available in sufficient quantities. This confirms the importance of active root growth for efficient Ca uptake by apple trees when applying Ca to the soil.