The Effect of Partial Defoliation at Different Times in the Season on Fruit Drop and Shoot Growth in Lord Lambourne Apple Trees

Six-branched trees were deblossomed on alternate branches and various defoliation treatments given. For the period of 7 to 30 days from the time of treatment, defoliations increased the compound-interest rates of fruit drop. After this period these rates of drop became equal to those of untreated trees and the relative differences in crop numbers established by this time persisted until harvest though the actual numbers still fell. The earlier in the season that the defoliations were applied the greater were the relative differences. The removal of spur leaves from branches bearing fruit caused greater drop than the removal of spur leaves from neighbouring deblossomed branches. The removal of leaves from extension and bourse shoots of fruiting or deblossomed branches had no significant effect upon fruit drop or shoot growth.

The removal of all flowers from alternate branches at mouse-ear caused more shoots to grow from these branches than from branches allowed to fruit. Removal, at pink bud, of spur leaves from either fruiting or non-fruiting branches increased the number of shoots on both branches, but removal deferred till later in the season had no effect.     

Effect of CPPU on fruit and shoot growth of apple

The effects of CPPU on the growth of fruits and bourse shoots of apple were examined by targeted applications of 20 mg I“1 CPPU to fruitlets and/or bourse-shoot and spur leaves. Treating fruitlets and fruitlets-plus-leaves stimulated fruit growth to a similar extent; fruit growth rate was temporarily suppressed when only the leaves were treated. Conversely, bourse shoot growth was stimulated by leaf and leaf-plus-fruit treatments. All CPPU applications reduced the content of fruit soluble solids and induced a paler yellowish- green fruit ground colour.     

Growth characteristic and sink strength of fruit at different CO2 concentrations in a Japanese and a Dutch tomato cultivar

The aim of the present study was to elucidate how fruit growth was limited by the source and sink capacities in a Japanese (‘Momotaro York’) and a Dutch (‘Dundee’) tomato cultivar. The two cultivars were grown hydroponically with a high-wire system in greenhouses for 25 weeks, and the growth characteristics and sink strength of fruit were determined. Fruits were pruned to four (4F) or one (1F) per truss. The latter were used to determine potential fruit growth, an indicator of fruit sink strength. Growth was also determined under normal (LC) and enriched (HC, 700 μmol mol⁻¹) CO₂ concentrations to examine the effect of source enhancement on fruit production. In both cultivars under normal CO₂, the growth rate of fruit pruned to 4F per truss was lower than that in 1F, indicating that maximum potential fruit growth was not achieved. Under HC conditions, fruit growth rate of ‘Dundee’ achieved in 4F trusses was lower than that in 1F. In ‘Momotaro York’ in HC, fruit growth in 4F trusses was close to potential. This implies that fruit growth was source-limited irrespective of CO₂ concentrations in ‘Dundee’ cultivar while fruit growth in ‘Momotaro York’ under normal and enriched CO₂ conditions was limited by source and sink strengths, respectively. Adjustments of cultural practices including increasing fruit number per truss and/or genetic approaches to enhancing fruit sink strength by breeding may improve fruit yields of Japanese cultivars under high source/sink conditions.     

Wood age and leaf area influence fruit size and mineral composition of apple fruit

Summary

The influence of wood age, fruiting position and leaf area within the tree canopy on fruit mineral content and quality for several apple (Malus domestica Borkh.) cultivars was investigated. Size and Ca, Mg and K content of individual fruit on one-year (lateral and terminal positions), two-year and older than three-year wood were compared for cvs Royal Gala, Braeburn, Granny Smith and Fuji. Fruit on two-year spurs and one-year terminals was generally larger at commercial harvest than that on one-year laterals and spurs older than three years. Flower receptacles at full bloom were larger and fruit growth rates were greater from 60 to 100 d after full bloom on two-year spurs than on one-year laterals. Fruit Ca and Mg concentrations and contents at commercial harvest were highest for terminal fruit, but there was no consistent difference between fruit from other positions. One-year terminals had the greatest primary and bourse leaf areas, two-year spurs were intermediate and one-year laterals had the lowest areas of both leaf types. Removal of 50% of primary leaves and/or removal of bourse shoots from clusters at bloom reduced fruit Ca content at commercial harvest for two-year spurs, one-year laterals and one-year terminals. Bourse shoot removal also reduced Mg content for all positions. However there was no effect of leaf removal on fruit size or K content. Ca content of individual fruit increased curvilinearly with increasing total spur leaf area for fruit on two-year spurs and one-year terminals but not for fruit on one-year lateral clusters. Terminal fruit with total spur leaf areas and fruit size similar to those on two-year spur fruit had higher Ca content.     

Relationship between early watercore development and leaf photosynthesis or partitioning of photosynthates in apple

Seasonal changes in leaf photosynthetic rate and partitioning of ¹³C taken up by leaves were compared in relation to the development of early watercore using susceptible ‘Orin’ and resistant ‘Fuji’ apples (Malus domestica Borkh.). There was no difference between the cultivars in leaf photosynthetic rate from mid-July to mid-October. The extent of watercore in ‘Orin’ increased from mid-July and peaked in late-August, followed by a decrease through mid-October, while no watercore was detected during the experimental period in ‘Fuji’. Fruit fresh weight and soluble solids content (SSC) were higher in ‘Orin’ than ‘Fuji’ during the earlier stages. Leaf dry weight of ‘Orin’ was higher than that of ‘Fuji’ throughout the experimental period. Accumulation of dry matter in the fruit increased in both cultivars and ‘Orin’ kept significantly higher level than ‘Fuji’ from mid-July to mid-October. The amount of ¹³C distributed to ‘Orin’ fruit at 5 days after labeling was significantly higher than ‘Fuji’ in mid-July just before watercore started to occur. ¹³C taken up by ‘Orin’ fruit with prevalent watercore was also higher than ‘Fuji’ in late-August but the difference was not significant. In mid-October when early watercore was gradually reducing, ¹³C recovered by ‘Orin’ fruit decreased and was significantly lower than ‘Fuji’. The difference of partitioning pattern of ¹³C between the cultivars was associated with the susceptibility to early watercore as well as the changes in fruit growth and SSC. The seasonal changes in the amount of ¹³C distributed to ‘Orin’ fruit were also related to the fluctuations in watercore severity. The results suggest that active phloem transport might be the cause of early watercore in our previous work, which might be induced by the increased partitioning of assimilates to the fruit during summer in susceptible ‘Orin’ compared to resistant ‘Fuji’ and not by the higher potential of leaf photosynthesis.     

The number of leaves required for floral induction and translocation of the florigenic promoter in mango (Mangifera indica L.) in a tropical climate

Mango flowering appears to be determined by a temperature-regulated florigenic promoter (FP) synthesized in leaves and translocated to buds in phloem. The number of leaves required for flowering was investigated in ‘Keitt’ and ‘Tommy Atkins’ mango trees exposed to tropical conditions in Colombia. Data were compared with a previous study conducted under cool, floral-inductive conditions in Florida (Davenport et al., 2006). Leaf-number treatments consisted of 0, 1/8, 1/4, 1/2, 1, 2, 3, or 4 leaves on each of 20–40 stems per branch. The long distance translocation experiment consisted of a terminal donor stem and five defoliated receiver stems on each treatment branch. Treatments were 0, 1, 3, or 5 leaves on the donor stem. Every treatment branch in both experiments was girdled to isolate it from the rest of the tree, and developing panicles were removed to stimulate lateral shoot initiation at a time when conditions were right for floral induction in those buds. Treatment stems bearing no leaves produced only vegetative shoots in both cultivars in both experiments. The minimum number of leaves per stem (1/8 of a leaf and 1/4 of a leaf) was sufficient to induce 6% and 1% reproductive shoots with 94% and 99% vegetative shoots in Tommy Atkins’ and ‘Keitt’ stems, respectively. Branches bearing 4 leaves per stem in ‘Tommy Atkins’ trees produced the maximum mean flowering response with 45% reproductive shoots and 55% vegetative shoots. The maximum ‘Keitt’ response was 22% reproductive and 78% vegetative shoots with 4 leaves per stem. The donor stem of the 1-leaf treatment and the donor and first receiver stem of the 3-leaf treatment in the translocation experiment were induced to flower in ‘Tommy Atkins’ trees. The more distal receiver stems from the donor were vegetative. The 5-leaf donor treatment-induced reproductive shoots as far as the third leafless receiver stem located 52 cm from the donor. Proportions of flowering shoots decreased with distance from the donor, and the level of the FP was apparently insufficient to reach the fourth and fifth receivers since their shoot responses were vegetative. Only vegetative shoot responses were obtained in the translocation experiment conducted in ‘Keitt’ trees. The leaf number and translocation experiment results support the hypothesis that far less FP is synthesized in both ‘Tommy Atkins’ and ‘Keitt’ leaves during warm, tropical conditions than is synthesized in ‘Keitt’ leaves exposed to cool, subtropical conditions.     

基于三维数字化仪的高纺锤形苹果树光截获率测定

利用三维数字化仪,结合Piaf Digit和Vege STAR软件,建立了13a生高纺锤形苹果树数字化模型,并对树体模型进行立方单元分割以及分析总冠层及冠层内各类型枝条的光截获率。结果表明:不同类型的枝条,光截获率(STAR值)有差异。大树的短果台副梢、长果台副梢、短营养枝和长营养枝的STAR值分别小于中树,中树小于小树;每棵果树的短果台副梢和短营养枝的STAR值分别小于长果台副梢和长营养枝;不遮阴枝条的光截获率比遮阴枝条大,并且短果台副梢和短营养枝因其它类型枝条遮阴减少的STAR值分别比长果台副梢和长营养枝大。果树由底部到顶部及由冠层中部到外部,光截获率逐渐增大,与用光量子探头(LS190)测得的透光率递增趋势相符。冠层STAR值越大,果树产量越高。因此,冠层光截获率能够作为冠层内部光分布特征的一个评价指标,并能有效指导果树管理,提高果实产量。     

Mobilization of nitrogen in the olive bearing shoots after foliar application of urea

Mature ‘on’ and ‘off’ ‘Manzanillo’ olives trees with three healthy branches of 10–12 cm in diameter were selected to determine changes in nitrogen levels in the bearing shoots after foliar application of urea. Each selected branch of each tree received one of the following treatments: (i) control without urea application; (ii) foliar application of urea to all the current-season leaves; and (iii) foliar application of urea to all the one-year-old leaves. Urea was applied in May, four days after full bloom in the ‘on’ year trees. Each treated leaf was immersed in a test tube containing a 4% urea solution and 0.1% Tween 20 for 5 s. Bearing shoots, composed of both one-year stems and leaves and current-season stems and leaves, were collected at intervals from the beginning of the experiment until 64 days after urea application. Nitrogen was determined in stems and leaves from each part of the bearing shoot, and in fruits during the ‘on’ year. Nitrogen uptake from the leaves was rapidly mobilized from the older to the current-season leaves of the bearing shoot, and thereafter to other storage organs of the tree or to the fruit, which is the largest nitrogen sink in the bearing shoot. No translocation of nitrogen from the current-season leaves to older leaves was observed. The rapid translocation of nitrogen from the younger leaves to other storage organs of the tree could explain the insensitivity of leaf analysis to detect excess nitrogen, since mature leaves from current-season shoots must be sampled to determine the nutritional status of the tree. The failure of leaf analysis to detect excess nitrogen may be a cause of nitrogen over-fertilization in olive orchards.     

The effect of forcing temperature on peony shoot and flower development

Pre-chilled potted plants of Paeonia ‘Coral Sunset’, ‘Monsieur Jules Elie’, ‘Sarah Bernhardt’, and ‘Karl Rosenfeld’ were placed in a range of controlled temperature regimes to ascertain the effect of temperature on the timing of shoot emergence and floral development. For all cultivars, warmer temperatures up to 25 °C lead to more rapid shoot emergence and flower development. Linear temperature responses adequately described the rate of development from shoot emergence to flower bud appearance, and from bud appearance to flower opening, but a curvilinear response was required to describe the time taken for shoots to emerge. There were significant differences between cultivars in the number of heat units required for shoot emergence, with the shoots of the slowest-developing cultivar, ‘Monsieur Jules Elie’, taking 50% longer to emerge than those of the most rapid, ‘Coral Sunset’. No significant differences were found among cultivars in the time taken from shoot emergence to flower opening, although the ‘split’ stage (when the bud opens sufficiently for petal colour to be observed) was slightly earlier in ‘Karl Rosenfeld’.     

Growth,biomass allocation and leaf ion concentration of seven olive (Olea europaea L.) cultivars under increased salinity

Olive (Olea europaea L.) is the major fruit tree in the Mediterranean region, often grown in locations where plants are exposed to increased salinity. To determine the effect of NaCl on shoot and root growth, dry matter allocation, leaf Na⁺ and K⁺ concentration, electrolyte (EL) and K⁺ leakage (KL), seven olive cultivars of different origins were grown in nutrient solution containing 0, 33, 66, 100 or 166 mM NaCl for three months. The general effect of salinity was linear and quadratic decrease of observed plant growth parameters. Different responses of tested cultivars to applied levels of salinity were found for stem dry weight, shoot length and number of leaves. As salinity increased, growth of ‘Manzanillo’ declined sharply, whereas ‘Frantoio’ was the most tolerant to growth reduction in most of the observed growth parameters. Allometric analysis showed that biomass allocation under salinity stress was similar in all cultivars, but the slope between shoot weight and total plant weight decreased as salinity increased. Since the higher allocation in roots was not found, it seems that salinity only slowed the above ground plant canopy growth. Sodium concentration in leaves of all cultivars increased as salinity increased with the highest increment reached when the salinity of nutrient solution was raised from 100 to 166 mM NaCl. Significant differences among genotypes were found in leaf Na⁺ and K⁺ concentration and K⁺:Na⁺ ratio, but they were not related to the growth rate. Generally, ‘Frantoio’ and ‘Oblica’ accumulated less Na⁺ and were able to maintain higher K⁺:Na⁺ ratios as compared to other genotypes. Electrolyte leakage and KL linearly increased with increasing salinity and the magnitude of the response depended upon the olive cultivar.     

Evaluation of basal media for micropropagation of four highbush blueberry cultivars

Murashige and Skoog medium (MS), woody plant medium (WPM), and a mixture of equal parts of MS and WPM (MW) were compared for in vitro shoot proliferation and rooting of four highbush blueberry (Vaccinium spp.) cultivars. During the multiplication stage, the shoots on WPM showed worse growth than the other shoots. The MW produced the best shoot growth. The shoots on MS grew well but tended toward hyperhydricity in the multiplication stage, especially in the case of ‘Bluecrop’ shoots. Rooting was worst in the shoots multiplied on WPM, while the best rooting percentage of ‘Bluecrop’ shoots was obtained on MS, and that of ‘O’Neal’ on MW. The rooted shoots developed a good root system and were easily acclimatized after potting.     

Long-term effects of (2RS, 3RS)-paclobutrazol on vegetative and fruiting characteristics of sweet cherry spurs

The long-term effects of an overall foliar paclobutrazol application (750 mg a. i. per tree) was tested on sweet cherry spur growth and fruiting. Leaves and fruits were counted on spurs situated on long upright shoots, during the year of treatment and in the following two years. Paclobutrazol significantly increased the mean number of leaves per spur during the three year study. It also significantly increased the number of fruits per spur on three year old spurs, whereas no differences were observed on two year old spurs. Furthermore, the chemical treatment led to a significant increase in the number of fruits per corymb at the base of one year old long shoots. Otherwise, paclobutrazol appeared to induce spur ramification in the year of treatment. The same year, these ramifications, which did not bear fruits, accounted for 16.5% of the total number of spur leaves. This phenomenon was probably due to a direct action of the chemical spray since almost no new ramifications were produced the following years. In addition to the known retardation of extension shoot growth, foliar application of paclobutrazol thus appeared effectively to enhance leaf and fruit production of the spurs, not only in the year of treatment but also during the two following years.     

Phenology of strawberry guava (Psidium cattleianum) in ReÂunion Island

Summary

The phenology of wild stands of strawberry guava (Psidium cattleianum Sabine) was studied at 100, 480 and 720.m over 2 years in ReÂunion Island. The shoots bore flower buds at the basal nodes, and vegetative buds at the apical nodes. Trees produced vegetative growth from September to December, flowers from November to January and fruit from February to June. Shoot growth was earlier at 100 and 720.m the first year, but were synchronized in the second year. Flowering and fruiting were also earlier at 100.m. The intervals between shoot emergence and flowering, and flowering and fruit maturity were strongly related to temperature, with base temperatures of 5.58C and 2.68C, and heat units requirements of 675 and 2,5528C.d, respectively. The number of shoots, flowers and fruit per branch varied across sites and years, unrelated to temperature. However, production was significantly higher at 720.m. Production was much lower after a hurricane. Flowering (y) was related to shoot production per branch (x) (log(y)=111.33.log(x); r².=.0.78), whereas the fruit set rate was highly variable between trees (26±100%). The number of fruits per branch (1±6) was possibly related to poor shoot growth or fruit set, but unrelated to the timing of the phenological events. It is expected that commercial orchards would be more productive than feral stands.     

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.     

Harvest and post-harvest apple fruit quality following applications of kaolin particle film in South African orchards

Sunburn on apples in the Western Cape region of South Africa can result in yield losses of up to 50%. Application of kaolin-based particle film (Surround^® WP) increases leaf and fruit surface reflectivity, thus potentially reducing heat load and sunburn. Trials were performed during 2002/2003 and 2003/2004 to assess the effectiveness of kaolin particle film in controlling sunburn on ‘Granny Smith’, ‘Braeburn’, ‘Fuji’, ‘Royal Gala’ and ‘Cripps’ Pink’ apples. Fruit quality and ripening were monitored following 1–4 months in regular atmosphere cold storage at −0.5 °C. Sunburn on exposed fruit was significantly reduced in ‘Granny Smith’ and ‘Fuji’. Kaolin treatment improved fruit colour of ‘Granny Smith’ and ‘Royal Gala’, and delayed starch conversion in ‘Granny Smith’ at harvest and during the early storage period but not thereafter. Incidence of watercore at harvest was significantly reduced by kaolin treatment, but this disorder disappeared during cold storage in both treatments. There were no effects on skin anthocyanin or phenolic concentrations in any cultivar compared to unsprayed fruit.     

Effect of NaCl salinity in the genotypic variation of cowpea (Vigna unguiculata) during early vegetative growth

Twenty-five genotypes of cowpea (Vigna unguiculata L. Walp.) were tested for salt-tolerance at the vegetative growth stage in pot in the greenhouse experiments at salinity levels of 0, 85, and 170 mM NaCl. Plant survival was the main criterion for classifying genotypes. Other criteria included the ion concentration (Na⁺ and Cl⁻) in root and shoot and biomass accumulation. Four local accessions (‘Paceño’, ‘Tardón’, ‘Sonorense’, and ‘Cuarenteño’), three accessions from California (‘CB46’, ‘CB27’, and ‘CB3’), and one accession from the International Institute of Tropical Agriculture (IITA) (‘IT82D-889’) survived at concentrations of both 85 and 170 mM NaCl and were classified as salt-tolerant, while ‘IT96D-666’, ‘IT89KD-288’, and ‘IT93K-734’ from IITA were classified as salt-sensitive. One local accession (‘Sesenteño’), three accessions from IITA (‘PEPH-V Wes-85’, ‘IT86D-719’, and ‘IT95K-1090-12’), and one accession from California (‘CB5’) were classified as moderately salt-tolerant. Eight accessions from IITA (‘IT96D-733’, ‘IT90K-277-2’, ‘IT91K-93-10’, ‘IT91K-118-20’, ‘IT90K-284-2’, ‘IT95K-1088-4’, ‘IT89KD-391’, and ‘IT94K-437-1’) and one from California (‘CB88’) were classified as moderately salt-sensitive. Biomass was affected by both 85 and 170 mM NaCl in all groups of genotypes, however, salt-tolerant and moderately salt-tolerant genotypes showed higher biomass than genotypes classified as moderately salt-sensitive and salt-sensitive. In all genotypes Cl⁻ concentration was higher in shoots than roots and increased as salinity increased. Similarly Na⁺ concentration increased with increasing salinity. However, in salt-tolerant and moderately salt-tolerant genotypes, Na⁺ concentration was more in roots than shoots, while in moderately salt-sensitive and salt-sensitive genotypes, Na⁺ was higher in shoots than roots.     

磷对板栗结实性能及产量的影响

试验结果表明,磷对板栗(Castanea mollissima Blume)雌花的形成数量有重要影响,结果母枝含磷量与母枝抽生结果枝数量和着生雌花数量呈显著正相关。板栗结果母枝含磷量比雄花母枝和营养枝分别高5.19％和5.27％。树体磷素含量水平与板栗雌、雄花枝比例和结果枝结栗苞数量也存在密切的相关性。在不同施磷水平下,结果枝粗度与果枝结栗苞数均具有显著的回归关系,但b值差异大。本研究结果在鄂东大别山区进行了大面积施磷肥示范,生产实践证明,施磷肥对板栗具有一致的增产效益。     

Effect of Leaf Number and Area on the Fruit Growth of Regular and Biennial Bearing Mango (Mangifera indica L.) Grown Under North Indian Conditions

Abstract

The optimum leaf number required for normal fruit growth in the regular bearing mango cultivar ‘Amrapali’ and the biennial bearing cultivars ‘Chausa’, ‘Dashehari’ and ‘Langra’ were studied by isolating individual fruits with known numbers of supporting leaves by shoot girdling at the time of fruit set. There were significant differences in the leaf area (249.01-1817.10 cm2), fresh weight (7.0-77.0 g) and dry weight (3.7-50.0 g) of leaves on shoots having 30, 20, 10 and 5 leaves as compared with control in different cultivars. In both types of cultivars, there was a progressive reduction in fruit size in terms of total fruit, pulp, peel, and seed weight with decreasing numbers of supporting leaves, however, a minimum reduction (2.4%) in fruit growth in ‘Amrapali’ was noticed with 30 supporting leaves. A nonsignificant difference in photosynthetic rate with varying number of leaves was found but its efficiency in leaves was higher in ‘Amrapali’ as compared with biennial bearing cultivars. Starch accumulation in the leaves was reduced by shoot girdling. The stomatal resistance of the leaves of girdled shoots was comparable with that of leaves on control shoots. In all the cultivars except ‘Amrapali’ it was observed that 30 leaves, the maximum retained on a shoot, could not support the growth of a single fruit to normal size. The data on rate of photosynthesis in different pool size of leaves and fruit growth in girdled and nongirdled shoots clearly show that fruit development depends not only on the current assimilates but also to a great extent on reserves. A 14CO2 feeding experiment showed a higher rate of carbon fixation in the leaves of girdled shoots than in the control shoots, but the translocation of 14C assimilated to the developing fruits on the girdled and control shoots was comparable. The results also indicated that developing fruits are major sinks for current photosynthates as more than 60 percent of the 14C exported from the treated leaf was found in the fruit in all instances.     

Effects of defoliation on fruit growth,carbohydrate reserves and subsequent flowering of ‘Hayward’ kiwifruit vines

A partial defoliation study was carried out on ‘Hayward’ kiwifruit vines with the aim of evaluating effects on fruit yield, changes in concentration of carbohydrates, and return bloom. At full bloom, ‘Hayward’ kiwifruit vines trained to the pergola system were submitted to 0% (control), 50% and 75% defoliation in the 2.0 m wide central horizontal area of the canopy. This area represents the vine ‘replacement cane zone’ (RCZ), whereas the remaining external area represents the ‘fruiting zone’ (FZ). Removing 50% of the leaves resulted in a small (−9 g in the RCZ and −3.3 g in the FZ), but significant, reduction in fruit weight compared to the control vines. More severe defoliation (75%) reduced fruit weight by 13 g in the RCZ and 7 g in the FZ. The defoliation treatment reduced the concentrations of starch and total soluble carbohydrates (glucose + fructose + sucrose) in the shoots and starch in trunk bark compared to those in control vines. The treatments caused a large reduction in return bloom, expressed as number of flowers per winter bud, by about 25% and 53% in vines with 50% and 75% defoliation, respectively.     

Gibberellic acid influences the production of malformed and button berries,and fruit yield and quality in strawberry (Fragaria × ananassa Duch.)

Experiments were conducted to observe the effects of foliar application of gibberellic acid on vegetative growth, flowering, fruiting and various disorders in ‘Chandler’ strawberry. GA₃ (75 ppm) was applied to the strawberry plants either during mid-November (at fruit bud differentiation stage), or mid-February (pre-flowering stage) or at both times. Fruit under control were sprayed with tap water only. Observations were recorded on vegetative attributes like crown height, crown spread, petiole length, leaf number, leaf area; flowering and fruit set, fruit size; production of albino, malformed and button berries, total yield and marketable fruit yield and quality parameters, like juice content, TSS, ascorbic acid contents, acidity etc. Results indicated that GA₃ (75 ppm) spray either during mid-November or mid-February or at both times has favourably influenced all vegetative attributes of ‘Chandler’ strawberry over control. Similarly, fruit set was increased, and production of malformed and button berries was reduced, but albinism remained unaffected. Although individual berry weight was reduced slightly, but fruit number, total as well as marketable yield was increased tremendously over control with no adverse effect on fruit quality parameters. In all, spraying GA₃ both during mid-November and mid-February was much more effective in achieving the desirable results than single application of GA₃ either during mid-November or mid-February.