Effect of agar,galactomannan and indole-butyric acid on in vitro rooting of the pear cultivar ‘Durondeau’ and apple rootstock cultivar ‘Marubakaido’

Summary

The influence of partial substitution of agar by galactomannans in culture media supplemented with different concentrations of indole-3-butyric acid (IBA) was studied on in vitro rooting of pear (Pyrus communis L.) cultivar ‘Durondeau’ and apple rootstock (Malus prunifolia Borkh.) cultivar ‘Marubakaido’. The galactomannans applied were obtained from Cassia fastuosa (cassia) and Cyamopsis tetragonolobus (guar gum) seeds. The results obtained with mixtures of agar and galactomannan (3 g l^–1 each) were compared with those from media solidified with a standard concentration of agar (6 g l^–1). The rooting of pear shoots was enhanced significantly in the presence of a mixture of agar plus cassia galactomannan compared to medium solidified with agar only. The modified media promoted a higher number of roots than the control, and increased the percentage of rooted shoots. A maximum of 84.8% rooting was obtained on half-strength MS medium (¹?2MS) supplemented with 0.49 µM IBA and solidified with a blend of agar plus cassia galactomannan. For the apple rootstock, only the number of roots per shoot was influenced significantly by the addition of galactomannan to the rooting medium. The highest number of roots per shoot was 16.67 on ¹?2MS medium gelled with a mixture of agar plus guar galactomannan supplemented with 4.90 µM IBA. The behaviour of the agar-galactomannan gel and the possibility of reduced costs when compared with systems containing only agar, suggest new biological and commercial applications for galactomannans.     

The influence of fungicides and gibberellin (A4+7) applications on russet control of ‘Golden Delicious’ apple fruit

Summary

Various fungicides, gibberellins (A₄₁₇) and their mixtures were tested for the control of russet of ‘Golden Delicious’ apple fruit in the major apple-growing area in Israel. Four foliar applications of captan, metiram, the strobilurins kresoxim-methyl, trifloxystrobin, azoxystrobin, or the polyoxin B compound Polar from the green tip stage to the end of the petal fall stage gave similar reductions in russeting, compared with the controls, but none eliminated it. Tank mixtures of the gibberellins (A₄₁₇) Regulex and Perlan with captan, each at full rate, did not improve russet control, compared with each component alone at the same rate. Similarly, both captan and trifioxystrobin, and the gibberellin (A₄₁₇) Cytolin or their mixtures at full rates provided similar significant level of control of russet on fruit. Fruit in the upper part of the tree had significantly more russet than fruit in the lower part of the tree, regardless of treatment applied. In addition, russet was more severe on fruits of trees grown in the west side of the row, than those of trees grown on the east side. Data suggest that factors other than fungicides, which may act by reducing russet-inducing microorganisms, may be involved in russet development.     

Effects of different rootstocks and training systems on the mineral composition of ‘Delicious’ apple leaves

Leaf mineral composition as affected by different rootstocks, cultivars, training systems and their combinations was measured during 1987 and 1988. Trees on M.7 had significantly higher concentrations of N, P and Fe, whereas those on MM. 106 maintained higher values of K, Ca, Mg and Mn during both years. Between cultivars, Red ‘Delicious’ showed greater accumulation of N, P, Mg and Fe but K and Cu levels were found to be more in Starking ‘Delicious’. All mineral nutrients except Ca and Mg accumulated more in spindle-bush trained trees than those under modified central leader system. The Mineral composition of Starking ‘Delicious’ grafted on M.7 rootstock and trained as a spindle bush produced the best yield efficiency and fruit quality, and fell within the normal range.     

Studies in Biennial Bearing: III. Growth Studies in ‘ON’ and ‘Off’ Year Trees

Plum crops in the UK are often uneconomically low because of unfavourable weather at blossom time leading to low fruit set. In view of the promising results obtained with fruiting hormones on other crops, the effects were investigated of mixtures of gibberellic acid, NN’-diphenylurea and 2-naphthoxyacetic acid applied to Victoria plum during the two months following full bloom. Large increases in set and subsequent yield were obtained with two applications. Treatment at 50% petal fall was detrimental to set, whereas treatment four weeks later was essential for improved set. Flowering in the year after hormone treatment was inhibited, the reduction being attributable to the increased crop load and to the use of gibberellin per se. The results are compared with those described by other workers using different cultivars, and the practical implications of hormone spraying discussed.     

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.     

Regeneration from in-vitro leaves of ‘Conference’ and other pear cultivars (Pyrus communis L.)

Summary

Regeneration of shoots from in-vitro grown leaf tissues of the pear cv. Conference was achieved at rates of up to 40%. The highest regeneration percentage was achieved using a phytohormone combination of benzylamino purine (5 mg 1^?1) and 1-naphthalene acetic acid (1.0 mg 1^?1) on a basal medium of Murashige and Skoog, to which had been added 200 mg I^?1 of the antibiotic cefotaxime. The percentage regeneration was reduced when a higher concentration of cefotaxime (400 mg 1^?1) was used. Cefotaxime had little beneficial effect on regeneration at a lower concentration of 1-naphthalene acetic acid (0.5 mg l^?1). Regenerated shoots were easily micropropagated, rooted and transplanted to soil. To date, the plants have a true-to-type phenotypic appearance. Regeneration was also achieved with other cultivars—‘Abbé Fetel’, ‘Doyenne d’Hiver’, ‘Doyenne du Comice’ and ‘Passé Crassane’—but percentage regeneration was lower and, apart from ‘Passé Crassane’, the regenerated shoots were weak and could not be subcultured.     

Evaluation of the activity of aqueous extracts of some organic waste materials on in vitro-cultured shoots of ‘M9’ apple rootstock

Summary

The present work investigated the effects of different aqueous extracts of organic waste compounds on growth, proliferation and photosynthetic activity in ‘M9’ (Malus domestica Borkh.) shoot cultures, with the aim of determining the feasibility of using in vitro cultures as a tool for the rapid evaluation of organic amendments in agriculture. Aqueous extracts of the following organic waste compounds: cow manure (CM), sugarbeet industrial waste (SB), mixed grape, poultry and municipal solid waste (GPM), and citrus pruning and industrial waste (CPI) were prepared at a rate of 1:10 (w/v) compound:distilled water. The basal media used in the proliferation phase were: (i) PM1, modified Murashige and Skoog (MS) enriched with 4.4 µM 6-benzyladenine (BA); (ii) PM2, as PM1 but with a reduced cytokinin concentration (1 µM BA) to evaluate possible hormone effects; and (iii) PM3, 4.4 µM BA with reduced salt strength (0.33 MS) to induce nutrient deficiency. Hormone-free medium with half-strength MS salts was used for rooting. All media were enriched with each extract at 0, 0.2, 2, 20 or 200 ml l^–1. Photosynthetic activity was measured on PM3 medium enriched with SB or CM. Standard culture conditions were 22° ± 2°C, with a 16 h photoperiod at 30 µmoles photosynthetically active radiation (PAR) m^–2 s^–1, but at 80 µmoles PAR m^–2 s^–1 to determine photosynthetic activity. Shoot weight increase in PM1 was not affected by the GPM and CPI extracts, while the growth trends of CM- and SB-treated shoots were described by a second-degree function with maxima at 2 ml l^–1 and 0.2 ml l^–1, respectively. Shoot proliferation for SB was represented by a quadratic curve (maximum at 2 ml l^–1), was linearly reduced as GPM increased, but was not affected by CM or CPI. Treatments did not significantly affect rooting percentage and root length; however root number was increased by SB at 2 ml l^–1.CO₂ fixation increased linearly with both SB and CM, despite reduced growth at the highest levels of extract.     

Pre-harvest drop control of ‘Red Delicious’ and ‘Jonathan’ apple (Malus domestica) as affected by the synthetic auxin 3,5,6-TPA

Summary

‘Red Delicious’, the main apple cultivar grown in Israel, and ‘Jonathan’, grown on a smaller scale, are prone to substantial pre-harvest drop. Spraying both cultivars with the synthetic auxin 3,5,6-trichloro-2-pyridyl-oxyacetic acid (3,5,6-TPA) reduced pre-harvest fruit drop and increased yield. Application of 40 mg l^–1 3,5,6-TPA 2 weeks before anticipated harvest (WBH), or 30 mg l^–1 3,5,6-TPA at 4 and 2 WBH gave the best results, and were as effective as 2,4,5-trichloro-phenoxypropionic acid (2,4,5-TP) which was the commercial product commonly in use until being withdrawn. There were no negative effects on fruit quality at harvest, or during 8 months of storage. Therefore 3,5,6-TPA can be recommended for routine use on ‘Red Delicious’ and ‘Jonathan’ apples in Israel.     

Performance of ‘Discovery’ apple on M.9, M.26 and MM.106 rootstocks at two densities

Summary

The apple rootstocks M.9, M.26, and MM.106 were evaluated for their efficiency in bringing ‘Discovery’ apple trees into production. The experiment, carried out over a ten- year period compared two planting densities at 1666 and 3333 trees per ha. Tree vigour differences between rootstocks were measured in term of trunk growth, tree volume, weight of branches pruned off and final weight of the above-ground parts of the trees. Fruit production is presented both as total yield and as the weight of first class fruit. Fruit colour development is also shown. Cropping efficiency is calculated and presented in relation to the different vigour measurements. The results confirm that ‘Discovery’ is slow to come into production. M.9 was the most productive rootstock, but due to vigour differences MM.106 gave the same yields per tree, although the latter had the lower yield efficiency. M.26 performed poorly; its vigour was similar to M.9 but it produced the lowest yields.     

In vitro colchicine-induced polyploid plantlet production and regeneration from leaf explants of the diploid pear (Pyrus communis L.) cultivar, ‘Fertility’

Summary

Polyploid plantlets, including triploid, tetraploid, and mixoploid, were induced from the European pear (Pyrus communis L.) cultivar ‘Fertility’ by in vitro colchicine treatment of leaf explants. The leaf explants were incubated in 0.4% (w/v) colchicine for 24, 48, or 72 h, then transferred to adventitious shoot-induction medium. Regenerated shoots were pre-selected according to their morphological characteristics when compared to control shoots from untreated shoot proliferation cultures. Shoots with putative polyploid morphological characteristics were maintained and proliferated. The ploidy levels of all putative polyploid individuals were analysed by flow cytometry and identified by chromosome counts of shoot tip tissue squashes. Polyploid shoots were rooted, and the resulting plantlets were transferred to the field. Polyploid plantlets had a higher specific leaf mass and larger stomata than those of diploid plantlets.     

Preliminary studies on the use of (2RS, 3RS)-paclobutrazol for fruitlet thinning and growth control of ‘Conference’ pear

Summary

Single foliar sprays of paclobutrazol (PP333) at 300, 1000 or 3000 mg H applied at three different stages from full bloom to petal-fall in a year of average initial sets . and fruit size were equally effective in thinning ‘Conference’ pear, increasing the proportion of large fruits at harvest, but decreasing their absolute numbers. Sprays applied nine days after petal-fall reduced initial sets less effectively and, applied 21 days after petal-fall, were ineffective. Thinning was completed within 25 days after petal-fall. Shoot extension was initially retarded at all three concentrations, but later increased, so that the total growth made during the season was not reduced. Single foliar sprays at 300 or 1000 mg l^?1 applied at 70% full bloom in a year of heavy set and small fruit size increased the numbers of large fruits in the >55 mm size category by 66% and decreased those of fruits <55 mm by a similar amount. The increase in the yield of fruits >55 mm and decrease of unsaleable <45 mm fruits was equivalent to about 3 and 2 t ha^?1 respectively from a total average yield of about 17.5 t ha^?1. In the same experiment, similar sprays counteracted the stimulation in the production of small fruits by sprays of gibberellic acid (GA) applied on the same day, but did not increase the harvest of large fruits. Sprays of paclobutrazol at 30 or 100 mg l^?1 applied two weeks after petal-fall and then on three successive occasions at two-week intervals inhibited total extension growth per shoot during the season without affecting initial or final sets, fruit size or flower bud production. Single sprays applied at 100 mg l?1 in July reduced total extension per shoot almost as effectively as the repeated sprays. For more effective control of ‘Conference’ shoot growth, paclobutrazol may have to be sprayed later in the season than commercially recommended. Applied as a blossom thinner, paclobutrazol may increase the yield of large fruits only in years of heavy set and small fruit size, requiring that applications be delayed until set can be judged.     

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.     

Effect of green tea extract powder on the vase-life of fresh-cut rose (Rosa hybrida L.) ‘Carola’ stems

To develop an innocuous, easy-to-use, and inexpensive preservative for the cut flower industry, green tea extract (GTE) powder was applied in the fresh-cut rose stem preservation process to exploit its high anti-oxidative and anti-microbial properties. The effects of 2.0 g l^?1 GTE powder in the vase solution on the vase-life and flowering profile of cut rose (Rosa hybrida ‘Carola’) stems were investigated. The effectiveness of GTE powder was also compared with other preservatives such as 2% (w/v) sucrose, 200 mg l^?1 8-hydroxyquinoline citrate plus 2% (w/v) sucrose, or 0.2 mM silver thiosulphate in the vase solution, with distilled water as a control. The results showed that, compared to the control, the 2.0 g l^?1 GTE powder treatment extended the vase-life and reduced the loss in fresh weight in cut rose stems in the vase solution. GTE at 2.0 g l^?1 provided the highest anti-bacterial activity (4.2 log₁₀ CFU ml^?1 on day-6) and prevented the decline in anthocyanin concentrations compared to that seen in the control stems, suggesting that GTE powder could be used as a preservative to extend the vase-life of fresh-cut rose flowers.     

The long-term effects of pre-planting soil fumigation on the growth and cropping of cvs Laxton’s Fortune and Cox’s Orange Pippin on M.2 rootstock,planted on land affected with a replant disease of apple

Soil fumigation of land affected by apple replant disease, using chloropicrin at 281 1 ha^-1 before planting-out, caused increases in shoot numbers, trunk girth and of 35% in total crop accumulated over 10 years for cv Cox’s Orange Pippin on M.2 rootstock. Chloropicrin at 1121 ha^-1 gave rise to a smaller response, and DD at 5621 ha^-1 was ineffective. Cv Laxton’s Fortune on M.2 showed little response to any treatment.     

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.     

Foliar Spray with Different Agrochemicals on Fruit Quality and Exportability of ‘Washington’ Navel Orange Fruit (Citrus sinensis L.)

The present study was carried out to improve fruit set, yield, quality, marketability, and exportability of ‘Washington’ Navel orange. Pre-harvest foliar sprays of GA₃, K, and Ca, either alone or combined, were applied at full bloom. The following treatments were applied: {control (T₁), 25 mg/L GA₃ (T₂), 2% K₂SO₄ (T₃), 25 mg/L GA₃ + 2% K₂SO₄ (T₄), 25 mg/L GA₃ + 2% Ca Cl₂ (T₅), 2% K₂SO₄ + 2% Ca Cl₂ (T₆), and 25 mg/L GA₃ + 2% K₂SO₄ + 2% Ca Cl₂ (T₇). All treatments improved fruit set, yield, physical and chemical characteristics, mineral content of leaves and fruit rind, and the percentage of exportable fruit in comparison to the control. Fruit set, fruit detachment force, peel firmness, and the mineral content of leaves and fruit rind were enhanced significantly with the combination of GA₃ + K₂SO₄ + Ca Cl₂ (T₇) in comparison to all other treatments and the control. Results indicated that all foliar combination treatments improved fruit quality and marketability, and increased the percentage of exportable fruit and reduced the defects of non-exportable fruit.     

Studies in the Development of the Strawberry: III. Flower-Bud Initiation and Development in Large-Fruited Perpetual (“Remontant”) Strawberries

Summary

Four N application rates generated a range of tree N status as indicated by leaf N concentrations in six year old trees of `Mission' almond (Prunus dulcis (Mill.) D. A. Webb). Leaf N concentrations were related positively with concentrations of amino acids - especially asparagine and glutamine - in phloem and xylem saps. A pulse of 1.25 kg N per tree was applied to trees previously receiving 0, 78, 157 or 313 g N per tree, annually. Apparent uptake of soil N into above-ground tree parts was determined over a 39 d period. N uptake was determined as the difference in the products of tree biomass and tissue N concentrations before and after the N pulse. Tissue N concentrations increased signi®cantly in trees previously receiving the two lowest N application rates, whereas trees previously receiving the high N treatments were unresponsive. Tree N contents (0 g N per year, and also 78 g N per year treatments) increased slightly in response to the N pulse, although statistical differences were not observed due possibly to high variability in biomass among trees. At the same time, the amino acid concentrations in phloem exudate and xylem sap were highest in trees grown under the highest N fertilization regime. We suggest that the high amino acid concentrations in the phloem and xylem saps are indicative of a larger pool of amino N cycling throughout the vasculature of high N-status trees. Our data indicate an inverse relationship between tree N status, amino acid concentrations in xylem and phloem saps and capacity for soil N uptake in ®eld-grown trees. These results represent the ®rst ®eld data to correlate the concentration of amino acids circulating in the plant vasculature with soil N uptake. A functional relationship between the amino acid concentrations cycling within the tree and the regulation of soil N uptake has, however, not yet been established.     

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.     

Effects of drought on fruit set,yield and quality of custard apple (Annona spp. hybrid) ‘African Pride’ plants

Summary

Studies were conducted to evaluate the effects of drought during flowering for both container- and field-grown trees, and during fruit development for container-grown trees, on subsequent growth, flowering, yield and quality of the custard apple ‘African Pride’ in subtropical Australia. Moderate drought (ψ_L=–1.5 MPa) reduced shoot growth by 20–30% and increased the number of flowers per lateral by about 40% compared with well-watered controls due to reduced apical dominance and increased lateral branching. Overall fruit set was not adversely affected by drought. Drought also increased the number of fruit harvested per tree by 47% compared with well-watered controls. This response was mainly due to the increase in flower number per tree. Drought reduced average fruit size by 11% possibly due to effects on cell division in the first 4–6 weeks after fruit set or on net carbon assimilation. In summary, mild to moderate drought during the flowering period and fruit set increased flowering without adversely affecting fruit set, but decreased fruit size.