Bud Drop Research Articles

Influence of flower bud density, flower bud drop and fruit set on apricot productivity

Flower bud density, flower bud drop and fruit set were studied for nine apricot cultivars in order to understand the influence of these variables on apricot biology and productivity. Cultivars in southern Spain were chosen as representatives of different flowering times and productivity. Results indicate differences among cultivars in the studied parameters. Low flower bud production, high flower bud drop and low fruit set were often recorded in mid- to late flowering cultivars. These traits subsequently led to poor yields. Early blooming varieties, which are frequently good producers, generally showed the highest flower bud density, medium flower bud drop and high percentage of fruit set. The influence of the cultivar was more determinant than the seasonal effect on fruit yield. This information should be useful to breeders for choosing the best parents for productivity.

Effect of aminooxyacetic acid and sugars on the vase life of Dendrobium flowers

We investigated the effect of sugars and aminooxyacetic acid (AOA) on Dendrobium ‘Jew Yuay Tew’ inflorescences bearing open flowers and flower buds. Glucose or sucrose in the vase water had no effect on vase life. AOA alone also did not improve vase life, but AOA together with sugars considerably increased it. The treatment suppressed bud drop, promoted bud opening, and delayed the time to senescence of open flowers. Its effect was counteracted by raising solution pH (which was 3.2) to 4.2 or higher. Bacterial counts in the vase solution were low at pH 3.2, but increased when the pH was raised. The pH of 0.5 mM AOA alone was initially about 3.0, but started to increase by day 8 of vase life and had reached pH 5 by day 12. When 4% glucose was added to this solution, the pH remained around 3 until day 20 of vase life. The combination of 0.5 mM AOA and glucose thus allows continuous uptake of water and dissolved sugars by the flower. It is concluded that the vase life of Dendrobium ‘Jew Yuay Tew’ flowers is limited by adverse water relations and can be improved by sugars if water uptake is maintained. # 2003 Elsevier Science B.V. All rights reserved.

Apricot flower bud development and abscission related to chilling, irrigation and type of shoots

Flower bud drop dramatically affects productivity in some apricot cultivars. The influence of different chilling and irrigation conditions on flower bud development and drop of the apricot cv. ‘Guillermo’ was studied. Flower buds from trees grown in three places, with different winter conditions, were collected periodically to compare their developmental stage. Slight differences in the developmental pattern were observed between the two coldest places. Just before bloom, flower buds from the warmest place were found to be more delayed. Also, flower bud development was compared in three irrigation treatments. The lack of autumn irrigation induced a slow development, but when irrigation was reinstated, the flower bud development was hastened. The suppression of irrigation in winter did not have an apparent effect on flower bud development compared with the more irrigated treatment. In flower buds of short shoots no important abnormalities were found, but they were in the analysed flower buds of long shoots. In ‘Guillermo’ cultivar a serious drop was recorded in every location or treatment. However, no correlation was found between accumulation of chill unit or irrigation treatments and flower bud drop or fructification. In long shoots, the heavy flower bud drops (more than 90%), together with the high number of malformed flower buds, indicate that they do not produce an acceptable fruit set in this apricot cultivar.

Comparison of postharvest properties of closely related miniature rose cultivars ( Rosa hybrida L.)

The miniature rose cultivar ‘Vanilla Kordana’ is a useful genetic resource for improving display life and ethylene resistance of miniature potted roses. To investigate the significance of ethylene production and sensitivity as determinants of display life two mutants (‘Goldy, Safari’) selected on external traits and one offspring (‘Champagner’) of ‘Vanilla’ were analysed. All cultivars exhibited a shorter postharvest life and higher ethylene sensitivity than ‘Vanilla’. The cultivar ‘Amber’, which was crossed with ‘Vanilla’ to produce ‘Champagner’, had the shortest display life of the investigated cultivars and was highly ethylene sensitive. In response to exogenous ethylene, ‘Vanilla’ and the related cultivars exhibited differences in display life, chlorophyll loss, leaf and bud drop. The two mutants had a clearly higher ethylene production than ‘Vanilla’, suggesting that this is the main reason for their shorter flower life. ‘Vanilla’ and the mutants did not show autocatalytic stimulation of ethylene production. The ethylene production in ‘Champagner’, which results from crossing of ‘Vanilla’ and ‘Amber’, was lower than in both parents and in the mutants. Ethylene exposure induced increased ethylene production in leaves and partly in flowers of the cultivars ‘Amber’ and ‘Champagner’. This autocatalytic ethylene production may be a major reason for the short display life of these two cultivars. The results indicate that not only initial ethylene production but also degree of autocatalytic stimulation is a major factor determining display life.

High Production Temperature Increases Postproduction Flower Longevity and Reduces Bud Drop of Potted, Miniature Roses 'Meirutral' and 'Meidanclar'

The effect of two temperature regimes (29 °C day/24 °C night and 24 °C day/18 °C night) and of a 4-hour night interruption, during production, was studied on postproduction flower longevity and bud drop of 'Meirutral' and 'Meidanclar' potted, miniature roses (Rosa L. sp.). High production temperatures increased postproduction flower longevity and decreased postproduction bud drop. In 'Meidanclar', the high production temperature increased incidence of malformed flowers. No effects of night interruption could be shown on either postproduction flower longevity or bud drop.

Involvement of ABA in postharvest life of miniature potted roses

Exogenous application of ABA (abscisic acid) to intact miniature potted rose plants (Rosa hybrida L.) resulted in deterioration of postharvest quality of two cultivars. Spraying with ABA increased leaf drop and accelerated flower senescence in ‘Vanilla’ and ‘Bronze’, while bud drop was only induced in ‘Bronze’. Application of ABA to detached rose flowers accelerated their senescence, indicating that the observed senescence promoting effect was not a secondary response resulting from ABA-induced leaf senescence and abscission. ABA-treatment increased ethylene production in ‘Bronze’ flowers, while no ethylene production was measured in flowers of ‘Vanilla’, or in the leaves of both cultivars. Pre-treatment with 1-MCP (1-methylcyclopropene) delayed ABA promoted flower senescence in ‘Bronze’, suggesting that the effect of ABA is at least partly mediated by ethylene. The senescence promoting effect of ABA on leaf drop and flower life of ‘Vanilla’ flowers was not counteracted by 1-MCP pre-treatment. The cultivar ‘Vanilla’ had a low ABA level at all flower stages, while ABA content of the ‘Bronze’ petals was high in buds, lower in open flowers, and increased during flower senescence. An increased ABA content after ethylene treatment in ‘Vanilla’ suggests that ethylene, natural or exogenous, can increase ABA levels of flowers.

Seasonal flowering of Dendrobium ‘Jaquelyn Thomas’ in Hawaii

The factors controlling Dendrobium ‘Jaquelyn Thomas’ flowering were evaluated using data collected from an experiment in which flowering observations were made over 5 years. The number of flower spikes per plant increased as plants aged, reaching a maximum at 3–4 years, and then declined. Flowers per spike declined as bud drop increased with aging. Spike length reached a maximum after 3 years and then declined to a length just above that produced by young plants. Bud drop was greatest in the coolest part of the year. The cyclic pattern of flowering with the lowest yield in winter became less pronounced as plants aged. Dendrobium flowering was apparently initiated about 4–5 months before a harvestable spike was produced. A negative correlation existed between daylength 4 months before harvest and spike yield. Minimum temperature in the 5th month before harvest was also significantly ( P = 0.001) and negatively correlated with spike yield per plant, the number of flowers per spike and spike length. Solar radiation 3, 4 and 5 months before harvest was negatively correlated only with spike yield. Spike length was positively, and bud drop negatively, correlated with maximum temperature in the month of harvest. Short days in the 4th month before harvest and low minimum temperature with overcast conditions 5 months before harvest were related to Dendrobium flowering.

A Volatile Ethylene Inhibitor Improves the Postharvest Life of Potted Roses

Pretreating `Victory Parade' potted miniature roses (Rosa hybrida L.) with photolyzed diazocyclopentadiene (DACP) inhibited the effects of exogenous ethylene (acceleration of leaf and bud drop). In an ethylene-free simulated interior environment, display life of the treated plants was also greater than that of the controls and similar to that of plants pretreated with the anionic silver thiosulfate complex (STS). DACP caused an increase in the binding constant for ethylene in petals and leaves of `Victory Parade' and `Cara Mia' (a cut-flower rose cultivar). Competitive kinetics for the effects of increasing ethylene concentrations on control and DACP-treated plants are consistent with the hypothesis that the effects of DACP are due to irreversible binding to the ethylene-binding site.

024 ETHYLENE EFFECTS ON MINIATURE POTTED ROSES

Increased rates of senescence and ethylene related damage of potted flowering plants have been observed in supermarket produce areas where flowers and climacteric produce are displayed together. Ethylene levels in produce areas were found to average 20 ppb. An open system of clear glass chambers with fiberglass lids was designed to simulate retail supermarket conditions. The chambers were kept in postharvest rooms where light level and temperature could be controlled. In a 3 by 3 by 3 Box-Behnken design, Sunblaze `Candy' miniature potted roses were exposed to three levels of ethylene, 20, 40, and 80 ppb, for 1, 2, and 4 days. The three light levels used were: 0, 7, and 14 μmol·m-2·s-1. Ethylene damage was based on leaf and bud drop and decreased flower longevity.

432 PB 177 ADDITIONAL SYMPTOMS OF BORON DEFICIENCY IDENTIFIED IN ALMOND

Boron(B) deficiency in almond (Prunus dulcis Mill.) is characterized by leaf tip scorch, leaf drop, twig dieback, brown gummy areas in the endocarp, and embryo abortion followed by nut drop in May. Additional symptoms revealed by our work include failure of flowers to set nuts and lateral bud drop. Lack of production in part or in all of the free canopy causes spurs to elongate leading to a “willow twig” symptom on the small fruitwood. This can be confused with the nonproductive “bull” syndrome or with virus bud failure (ABFV or PRSV). Comparative leaf, pericarp, or kernel analysis in May gave a better indication of low B than did leaf analysis in August. In August, analyzing the hulls (mesocarp and exocarp) gave better separation between deficient and adequate trees than did leaf, kernel, or shell analysis. B critical levels for almond leaves should be re-evaluated since deficiency symptoms occur at currently accepted “adequate” levels.

Anti-ethylene Treatments for Potted Christmas Cactus-Efficacy of Inhibitors of Ethylene Action and Biosynthesis

Spraying flowering plants of Schlumbergera truncata (Haw.) `White Christmas' with aminoethoxyvinylglycine (AVG), an inhibitor of ethylene biosynthesis, did not prevent the rapid loss of flower buds caused by exposure to 1 μl of ethylene/liter. Treatment with the silver thiosulfate anionic complex (STS) strongly inhibited such effects. The rate of bud drop in ethylene-free air (interior environment room) was somewhat reduced by AVG treatment, although total display life of treated plants was not significantly different from that of the controls. STS treatment reduced the rate of bud drop, and increased display life by 20 %.

Postproduction Performance of Potted Rose under Simulated Transport and Low Irradiance Levels

Miniature flowering potted `Orange Rosamini' rose plants (Rosa × hybrida) were placed directly from production into simulated transport (STR) for 3 days at 5C and then into a retail handling treatment for 0, 1, 2, or 4 days. In the retail handling treatment, plants placed at 1 W·m-2 were then moved into a final postproduction irradiance level of 4 W·m-2; plants placed at 4 W·m-2 were then moved into a final postproduction irradiance level of 1 W·m-2. Also, a no-STR control treatment, plants placed directly into final postproduction environment (no transport or retail handling treatment), was included. All plants were placed into a final postproduction irradiance level (1 or 4 W·m-2) for 3 weeks to evaluate the effects of postproduction irradiance. The retail handling and postproduction environments were maintained at 20 ± 1C, 1 or 4 W·m-2 of irradiance (12 hours daily) from cool-white fluorescent lamps, and relative humidity (RR) of 60% ± 5% to simulate retail and/or consumer home conditions. Little difference was observed due to retail handling treatment or postproduction irradiance after 1 week. At weeks 2 and 3 of postproduction, there were 40% to 50% more open flowers on the no-STR plants maintained at 4 W·m-2 than on those maintained at 1 W·m-2 or on STR plants maintained at 1 or 4 W·m-2 postproduction irradiance. At week 3 of postproduction, plants with STR maintained at 1 W·m-2 had no buds showing color, while those maintained at 4 W·m-2 had three to five buds showing color. However, the no-STR control plants had one bud showing color at week 3, regardless of postproduction irradiance level. These results indicate that the detrimental effects of transport, i.e., bud drop, likely can be minimized by high postproduction irradiance levels following transport.

Effect of Different Day Temperatures on Flowering and Fruiting in Tosa Buntan Pummelo (Citrus grandis (L.) Osbeck).

The effect of different day temperatures during winter and spring seasons on the flowering and fruiting of 3-year-old potted Tosa Buntan pummelo (Citrus grandis (L.) Osbeck) trees grafted on trifoliate orange (Poncirus trifoliata Raf.) rootstock was investigat-ed. The experiment was conducted in growth chambers with setting day temperatures of 15°C, 20°C, 25°C, 30°C and 35°C, while night temperature in each chamber was set at a constant 10°C. The temperature treatments were started on December 18, 1989 and terminated on May 1, 1990, except for the 15°C day temperature treatment which lasted until June 11, 1990. After the temperature treatments in the growth chambers, all trees were grown in the same way in the field condition until harvesting time of November 15, 1990. The lowest day temperature treatment of 15°C needed considerably more days to flower bud initiation and greatly inhibited flower bud development, thus all flower buds in this regime dropped before and after their opening. Higher day temperature treatments led to a reduction in the number of days to flower bud initiation, flower opening and the end of flower opening and physiological fruit drop. A large number of leafy inflorescences were observed at higher day temperatures than at lower day temperature treatments. Higher temperatures also increased the rate of flower bud drop, decreased opening flower number, flower weight and petal length, and reduced fruit set on both leafless and leafy infloresc-nces. The fruit set of leafy inflorescences was higher than that of leafless inflorescences in all treatments in which setting of fruit was observed. At the 20°C day temperature regime, flower open number, flower weight, petal length and fruit set were highest among the treatments. The 20°C day temperature treatment produced fruit lower in weight and in rind coloring, compared to those at other higher day temperature treatments. Day temperature treatments over 20°C produced larger fruit with pyriform shape and thicker peel, increased TSS content except for 35°C, and decreased citric acid content in juice in mid-November 1990. 30°C and 35°C treatments gave gaps at axial parenchyma in all fruit, and 35°C treatment also gave granulation in juice sacs in all fruit at harvest.

Intergeneric hybridization in pigeonpea. I. Effect of hormone treatments

Attempts to cross Cajanus cajan with Atylosia albicans, A. cajanifolia, A. grandifolia, A. mollis, A. platycarpa, A. sericea and A. volubilis resulted in varying degrees of success. Hormone treatment (gibberellic acid and kinetin) increased pod-set and the number of seeds per pod. Hormone treatment among the unsuccessful crosses delayed bud drop by 3–4 days, which prolonged ovule development. Our results indicate that treatment with hormones helps post-fertilization development and leads to improvement in the rate of crossing success.

Selection and Inbreeding in Amphidiploid Dendrobium (Orchidaceae)1

Abstract Inbred progenies originating from the amphidiploid Dendrobium × Jaquelyn Thomas ‘Y166-1’ were produced through sellings, sibmatings, and backcrosses. An outcross was also included. Selection and inbreeding were effective in increasing flower size and improving color purity. The characters of flower size, flower color, scape length, total initiated flowers, vase life, and bud drop were primarily influenced by parental genotypes since inbreeding decline was not apparent. Continued inbreeding of individuals selected for larger, whiter flowers led to decreased numbers of racemes and shorter plants.

Morphological and physiological characters affecting flower drop and fruit set of tomatoes at high temperatures

Seven tomato cultivars and lines were studied under high temperature conditions. Fruit set varied between 77.3% in the heat tolerant cv. Hotset, 62% in cv. Gamad and 16.3% in the most sensitive cv. Hosen-Eilon. The characters contributing to low fruit set were bud drop, splitting of the antheridial cone, style exsertion and reduction of the quantity and/or functionality of the gametes. Employing the above characters as criteria for selection, fruit set of an F4 line, phenotypically similar to the sensitive parent, was improved to 63.1%. Improved fruit set, 87.6%, was also obtained in an F1 hybrid between ‘Hotset’ and ‘Gamad’. The importance is discussed of various easily recognizable flower components contributing to satisfactory fruit set under high temperatures and their possible use in breeding is elaborated.

The Prevention of Flower Bud and Leaf Abscission in Pot Roses during Simulated Transport1

Abstract Pot roses (Rosa hyb. cvs. Pink and Orange Margo Koster and Red Garnette) were sprayed with naphthaleneacetic acid (NAA) or 6-(benzylamino)-9-(2-tetrahydropyranyl)-9H-purine (PBA) prior to simulated truck shipment which lasted 5 or 6 days to study the effect on flower bud and leaf abscision and on leaf senescence. “Shipment” under refrigerated conditions (1-3°C) prevented bud and leaf abscission. ‘Red Garnette’ and ‘Orange Margo Koster’ had little or no bud and leaf abscission even at a warm “shipping” temperature (20-22°C); however, ‘Pink Margo Koster’ was severely affected. Observations under “home conditions” for 10 days after this warm “shipping temperature” revealed that all 3 cultivars had severe leaf senescence. NAA spray (15 and 30 ppm) severely accelerated leaf abscission and senescence. NAA prevented bud drop, but the buds did not open. PBA (50 ppm) greatly reduced leaf abscission both during “shipment” and in “home conditions”. PBA also prevented bud drop and flowers subsequently opened normally.

Hormonal Regulation of Pedicel Abscission in Begonia Flower Buds

AbstractIn order to analyse the hormonal regulation of flower bud shedding in Begonia, levels of indoleacetic acid (IAA), abscisic acid (ABA) and ethylene were determined in buds and pedicels. The translocation and metabolism of 14C‐labeled IAA in pedicel segments were also studied.In a monoecious Begonia fuchsioides hybrid, abscising male flower buds contain about 1% of the IAA present in non‐abscising female flowers. In a male Begonia davisii hybrid, the seasonal variation in bud drop coincides with changes in the IAA content of the buds, while also the release of IAA from the bud to the pedicel is hampered.Abscission zones of these pedicels always contain abscission promoting ethylene concentrations. The tissue is prevented from responding with abscission by IAA from the flower buds. The buds also contain ABA but without influencing abscission considerably.Pretreatment with ethylene or ABA does not affect IAA transport in pedicel segments. The rate of this transport is 4–6 mm × h–1:; the capacity increases with the transverse area. In young segments, IAA is decarboxylated and also otherwise metabolized.

Inciting Bud Drop and Flower Deterioration of Camellias by a Camellia Bud Mite in Alabama134

Inciting Bud Drop and Flower Deterioration of Camellias by a Camellia Bud Mite in Alabama134