Bud Retention Research Articles

The effect of evaporative cooling on yield and flower bud retention during spring on pistachio cultivar ‘Ariyeh’ (Pistacia vera L.) in a climate with moderate winter chilling and high spring temperatures

The effect of evaporative cooling on yield and flower bud retention during spring on pistachio cultivar ‘Ariyeh’ (<i>Pistacia vera</i> L.) in a climate with moderate winter chilling and high spring temperatures

Utilizing Pruning and Leaf Removal to Optimize Ripening of Vitis riparia-Based ‘Frontenac Gris’ and ‘Marquette’ Wine Grapes in the Northern Great Plains

Experiments were conducted to evaluate the effects of three pruning levels (20, 30 and 40 nodes per vine) and three fruit-zone leaf removal levels (0%, 50%, and 100%) on the yield and fruit quality of Frontenac gris and Marquette wine grapes in a northern production region. The study was conducted at three North Dakota vineyards located near Buffalo, Clifford, and Wahpeton, North Dakota, in 2011 and 2012. Increasing the number of buds retained increased yields and reduced pruning weights in both cultivars. Frontenac gris and Marquette yields were greatest when vines had 50% of the fruit-zone leaves removed due to heavier clusters, suggesting that the 100% fruit-zone leaf removal level was too severe. Individual berries in clusters were also heavier when vines were pruned to retain 40 buds. Frontenac gris fruit quality was similar both years and was not influenced by pruning or leaf removal levels. Marquette fruit total soluble solids content was greater in 2012 due to the warmer and longer growing season. Marquette fruit titratable acidity was lower when 100% of the fruit-zone leaves were removed. These results suggest that for the two cold-hardy hybrid wine grapes used in this study, greater bud retention levels should be investigated. Results also warrant further research into cultivar adaptiveness to northern Great Plains conditions. With further research, it is anticipated that wine grape cultivars and management practices will be identified to produce acceptable yields and fruit quality for commercial wine grape production.

Alternate bearing in pistachio (Pistacia vera L.): a review

In this review, the main internal and environmental hypotheses regarding alternate bearing and abscission of inflorescence buds and also, the methods to mitigate this physiological phenomenon have been investigated. Alternate bearing is annually fluctuating heavy (‘on’) and light (‘off’) crops, which occurs in most fruit trees. There are multiple visible causes, decreased shoot growth and flower buds or imperfect flowers, but all occur in association with a heavy crop, suggesting a carbohydrate resource limitation to shoot growth, or flower initiation, induction or differentiation. Pistachios bear on 1-year-old shoots from axillary buds produced the previous year. The visible mechanism is bud abscission on current season’s growth during ‘on’ years and bud retention in low crop load (‘off’) years. Though bud abscission is visible, the underlying cause is unknown. This review classifies the multiple hypotheses as internal, genetic, carbohydrate resources and hormones or environmental, abiotic and biotic stresses. Our examination of potential hypotheses and recent research suggests alternate bearing in pistachio is a result of the carbohydrate resource limitation generated by the heavy ‘on’ year crop maturation. However, the specific signal producing bud abscission is unknown. Alternate bearing in pistachio can be mitigated by a vigorous rootstock, particularly if combined with proper pruning. We hypothesize the vigorous rootstock may produce a better carbohydrate resource status through a larger tree with more leaf surface area. The pruning does not address the bud abscission but alters the ratio of non-bearing to bearing shoots, resulting in a lower alternate bearing index. Furthermore, we conclude alternate bearing in pistachio, while a within shoot phenomenon, can be triggered by severe environmental events that damage a current crop.

How potassium deficiency alters flower bud retention on cotton (Gossypium hirsutum L.)

ABSTRACTPotassium (K) is fundamental for plant growth and development but despite the increased quantities of fertilizers applied, incidents of K deficiency are commonly observed. The objective of this study was to record the effects of K deficiency during cotton’s (Gossypium hirsutum L.) early reproductive stage on carbohydrate content and metabolism, total antioxidant capacity and oxidative damage of cotton flower buds as well as the physiology of the leaf, subtending to the flower buds. Growth chamber experiments were conducted using cotton cultivar DP0912 and treatments consisted of normal K and deficient K fertilization for the duration of the experiment. Potassium deficiency resulted in significant oxidative damage in the cotton flower buds, despite the substantial increase in their total antioxidant capacity. Sucrose metabolism of the flower buds was markedly affected resulting in significant reductions in all non-structural carbohydrate concentrations. Furthermore, K deficiency disturbed leaf physiology leading to increased membrane damage, decreases in chlorophyll and carotenoid content and ultimately leaf photosynthetic rates. Concomitant increases in specific leaf weight under K deficient conditions indicated reductions in photoassimilate translocation, which in conjunction with the disruptions observed in flower bud sucrose metabolism, due to the insufficient antioxidant response, resulted in significant decreases in flower bud retention.

Planting Angle and Meristem Management Influence Sweet Cherry Canopy Development in the “Upright Fruiting Offshoots” Training System

Upright Fruiting Offshoots (UFO) is a novel high-density training system for sweet cherry (Prunus avium L.) that produces fruit on multiple vertical leaders (“offshoots”) arising from a cordon-like trunk. The promotion of sufficient upright shoot number and uniform shoot distribution during establishment are key to development of this training system. Trunk angle, meristem management (selective bud retention and removal), and cordon height at establishment were evaluated for influence on shoot number, shoot distribution, total shoot length, and early fruiting potential. At planting, trunk angles of 45° or 60° from the horizontal resulted in increased shoot growth compared with 30°, and also increased shoot distribution when bud selection was not imposed. A cordon height of 45 cm increased total shoot length by 20% compared with a 60-cm cordon height. Bud selection (retaining buds for optimal upright shoot distribution and removing all others) improved canopy development by reducing the number of shoots in the terminal third of the cordon and increasing the number of shoots in the basal and middle thirds compared with no bud selection. Bud selection reduced fruiting potential in the 2nd and 3rd years compared with unmanaged treatments, but subsequently surpassed those treatments in projected annual yield in Year 4 and cumulative yield in Year 5. Bud selection increased total and average shoot length, and improved distribution while moderating early crop load potential. Planting angle, cordon height, and bud selection significantly impact canopy establishment of UFO trees by affecting shoot number, length, and distribution.

Increased Night Temperatures During Cotton's Early Reproductive Stage Affect Leaf Physiology and Flower Bud Carbohydrate Content Decreasing Flower Bud Retention

AbstractHigher than optimum temperatures during cotton's (Gossypium hirsutum L.) growing season is a common occurrence in cotton‐growing areas around the world with negative consequences on productivity. According to climate projections, night temperatures are expected to increase more than day temperatures. The objective of this study was to monitor and record the effects of higher than optimum night temperatures during cotton's early reproductive stage on physiological (photosynthesis, respiration and membrane damage) and biochemical (leaf adenosine triphosphate (ATP) levels, as well as glutathione reductase (GR) content and soluble carbohydrate concentrations of the leaf subtending the flower buds. Number, dry weight, carbohydrate concentrations and GR levels of flower buds were also measured at the end of the experiment. Growth chamber experiments were conducted using cotton cultivar ST 5288 B2RF and treatments consisted of normal day/night temperatures (32/24 °C) and high night temperatures (32/30 °C) for 7 days at squaring (approximately 4 weeks after planting). The results indicated that high night temperatures had an immediate effect on leaf respiration rates and membrane damage by significantly increasing them compared to the control and a similar pattern was observed on leaf photosynthesis and ATP levels that were markedly decreased. Leaf GR levels were also substantially increased under conditions of high night temperatures, in contrast to flower bud GR content which remained unaffected. High night temperatures had a significant effect on leaf carbohydrate concentrations resulting in significant decreases in hexose, sucrose and starch levels. Nevertheless, flower bud sucrose content was substantially increased under conditions of high night temperatures, while hexose content was decreased and starch concentrations remained unaffected. A detrimental effect of elevated night temperatures on the number of flower buds per plant and on the dry weight of flower buds was observed, and it was concluded that high night temperatures had a negative effect on cotton flower bud production due to disruptions on flower bud carbohydrate metabolism as a result of the insufficient GR response.

Decreasing the concentration of IBA or combination with ethylene inhibitors improve bud retention in semi-hardwood cuttings of hazelnut cultivar ‘Tonda Gentile delle Langhe’

The effect of two concentrations (500 and 1000 mg L −1) of indole-3-butyric acid (IBA) and the combination of IBA treatments (1000 mg L −1) with two ethylene inhibitors, 1-MCP (1-Methylcyclopropene) and AgNO 3, on adventitious root formation and bud retention of semi-hardwood cuttings were investigated in hazelnut ( Corylus avellana L.) cultivar ‘Tonda Gentile delle Langhe’. The IBA 500 mg L −1 treatment promoted percentages of rooting (70.0%) similar to IBA 1000 mg L −1 treatment but reduced bud abscission resulting in 56.3% of rooted cuttings with at least one bud retained. The use of 1-MCP and AgNO 3 in combination with IBA 1000 mg L −1 treatment reduced bud abscission without modifying the rooting response.

Contributions of short- and long-shoots to yield of ‘Kerman’ pistachio ( Pistacia vera L.)

The canopy of a mature ‘Kerman’ pistachio ( Pistacia vera L.) tree is composed of two types of shoots: short-shoots composed entirely of preformed nodes, and long-shoots composed of both preformed and neoformed nodes. Since the production of these two types of shoots is known to be related to rootstock and rootstock influences yield of pistachio the relationship of these two types of shoots to yield was investigated during two cropping years. Individual short-shoots produced significantly less yield and had fewer fruit clusters per shoot compared with long-shoots, but collectively produced 55–60% of the total yield. Long-shoots positively affected yield components in one year, but had no effect in the other year. Whether the differences in the one year were due to canopy position and light interception or differences in the carbohydrate allocation within the two types of shoots could not be determined from the current data. Long-shoots initiated more inflorescence buds, although inflorescence bud formation was restricted to the preformed growth and only the 3–4 earliest neoformed nodes. However, when expressed as a percentage, long-shoots retained a lower percentage of initiated inflorescence buds, compared with short-shoots. Regardless of shoot type, less than half of the retained inflorescence buds produced mature fruit clusters. Thus, inflorescence bud retention, a previously hypothesized mechanism of pistachio alternate bearing, may not be the primary limiting factor to yield in pistachio.

Effects of Time of Foliar Application of Nitrogen and its Concentrations on the Flower Bud Retention in Pistachio Trees

Effects of Time of Foliar Application of Nitrogen and its Concentrations on the Flower Bud Retention in Pistachio Trees

Potential of ethephon, NAA, NAD and urea for thinning pistachio fruitlets

Abstract Alternate bearing, the occurrence of high yield ‘on’ year followed by low yield ‘off’ year, is striking in pistachio ( Pistacia vera L.). Floral buds of pistachio are formed a year before bloom, but abscise during the years with heavy crop (‘on’ year). Abscission of floral buds is due to competition between growing seeds on 1-year-old shoots and developing buds on current season growth. We studied the effects of chemical fruit thinning on alternate bearing and nut characteristics in a commercial orchard of ‘Owhadi’ pistachio cultivar during 2003–2004 in Rafsanjan, Iran. In both years, ethephon (100 and 200 mg l −1 ), naphthaleneacetic acid (NAA) (125 and 250 mg l −1 ) and urea (2.5 and 5%) were applied to the branch units of each individual ‘on’-year trees. The results showed that ethephon at both concentrations significantly increased fruit thinning and floral bud retention for the subsequent year. Other treatments also increased fruit thinning and floral bud retention but were inferior to ethephon.

GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEAN

GENERAL COMBINING ABILITY EFFECTS FOR REPRODUCTIVE HEAT TOLERANCE IN SNAP BEAN

Influence of rootstock on the productive behaviour of ‘Orange Red’ apricot under Mediterranean conditions

Introduction. 'Orange Red' is an apricot cultivar released in the United States and characterised by large fruit of very good quality for both the fresh market and processing. For this reason, this cultivar is greatly appreciated in Europe, especially in France. However, its production is erratic under Mediterranean climate conditions. Materials and methods. The influence of two rootstocks ('Manicot' apricot and 'GF31' Myrobolan plum) on the pro- ductive behaviour of 'Orange Red' was studied under Mediterranean conditions in Murcia (Southeast Spain). Results and discussion. 'Orange Red' grafted onto 'GF31' Myrobolan flowered slightly later than those grafted onto 'Manicot' apricot. However, differences in the date of ripening of fruits were small. On the other hand, the percentage of flower bud reten- tion and levels of floral fertility were higher when 'Orange Red' was grafted onto 'GF31' than onto 'Manicot', resulting in higher yields and fruits with a smaller weight. The increase in flower bud retention of 'Orange Red' grafted onto the rootstock 'GF31' was the main factor responsible for the increase in yield observed with this rootstock. Conclusion. Interaction between the cultivar and rootstock is presented as an interesting strategy for cultivar adapta- tion to different climatic areas. Spain / Prunus armeniaca / climatic factors / rootstocks / graft compatibility / flowers / fruit / yields

Urea Combined with 6-Benzyladenine Applied to the Foliage of Pistachio Trees during Nut-fill Reduced Floral Bud Abscission during the “On” Crop Year and Increased Yield the Following “Off” Crop Year

Alternate bearing of pistachio (Pistacia vera L. cv. Kerman) is a significant problem in California. Excessive abscission of floral buds beginning in June and intensifying at the time of seed development (nut-fill) in July during the “on” year results in the next year's “off” crop. While the mechanism resulting in alternate bearing in pistachio has been identified, its physiological basis has not and there is no satisfactory horticultural practice to even out alternate bearing. Bud retention in pistachio was increased 3-fold and 2-fold for two successive years, respectively, on branches bearing greater than 70 nuts per cluster (an “on” crop) basal to the shoot bearing the buds for next year's crop with foliar applications of 0.25% N as low-biuret urea combined with 25 mg 6-benzyladenine per liter applied in early June and early July. In Sept. 1997, the crop produced by the buds treated in 1996, an “on” crop year, was harvested. The untreated control trees produced an “off” crop, 7.6 kg fruit per tree, yielding 0.5 tons split nuts (dry weight) per acre. Trees treated with 0.25% N as urea combined with 25 mg 6-benzyladenine per liter on June 1 and July 1 yielded 16.4 kg fruit per tree, resulting in 1.14 tons split nuts (dry weight) per acre (P ≤ 0.05).

Position of cut, bud retention and auxins influence rooting of Pistacia chinensis

The effects of growth regulator concentration, bud retention and distance from the basal bud to the base of the cutting on rooting were investigated on Chinese pistache ( Pistacia chinensis Bunge.). Cuttings collected on 16 May 1994 were cut either immediately above or below the sixth bud counting from the terminal bud and buds four, five (and six if present) were either retained or removed. The cuttings were then dipped in 0, 7.5, 15, or 22.5 g l −1 indolebutyric acid (IBA). Cuttings given 15 g l −1 IBA with buds retained and stems cut below the sixth bud produced more primary and secondary roots with longer primary roots than the other treatments. On 18 May 1994, 1 cm of the basal ends of cuttings were treated with 0, 5, 10, or 15 g l −1 IBA in factorial combination with 0, 5, or 10 g l −1 naphthaleneacetic acid (NAA). Cuttings receiving 5 g l −1 IBA + 5 g l −1 NAA produced more rooted cuttings than those in the other treatment combinations.

Mechanical Topping Mitigates Alternate Bearing of `Kerman' Pistachios (Pistacia vera L.)

The effects of four mechanical pruning treatments [hedging, topping, hedging/topping, and hand-pruning (control)] on nut yield, nut quality, alternate bearing, and growth of 14-year-old female `Kerman' pistachio trees on Pistacia atlantica L. rootstocks were assessed. A single pruning was done before an “off,” or low-crop, year followed by retopping of those treatments incorporating topping the first year. Over 7 years, yields of hedged/topped and topped trees were equal to those of control trees, while hedged trees produced significantly less. The incidence of nonsplit shells and blank nuts were not affected by pruning. Nuts weighed more all years for hedged/topped and topped trees than for the others. Alternate-bearing indices within 7 years were lower for pruning treatments incorporating topping. Topping mitigated the fluctuating annual vegetative growth pattern and resulted in 27% of the shoots retaining buds through three successive alternate-bearing cycles after the year of treatment. Hedged/topped and topped trees had significantly less alternation in annual girth growth than control or hedged trees. These results demonstrated that two successive seasons of mechanical topping, started before the off year, produced changes in shoot growth, trunk growth, and bud retention that mitigated alternate bearing through three biennial cycles, without decreasing yield. Thus, severe annual hand-pruning could be used to prevent or minimize alternate bearing of pistachios.

DELAYED COSTS OF REPRODUCTION, DEFOLIATION, AND SHADING IN PISTACIA VERA L. CV. KERMAN: BUD ABSCISSION AND DRY WEIGHT ALLOCATION TO BUDS, LEAVES, CURRENT AND PREVIOUS-YEAR SHOOTS

Trees that fruited during 1990 retained 67.3% of the inflorescence buds produced per branch in 1991 compared to 63.1% for trees that were defoliated immediately after harvest in 1990 and 21.3% by trees that were fruiting in 1991. Shading reduced bud retention similar to fruiting. Defoliation after nut harvest accentuated the delayed costs of reproduction caused by previous season's fruiting whereas shading produced significantly greater immediate costs. Shading effects on the allocation of carbon to buds, leaves and shoots were similar to those of fruiting. Leaf net photosynthesis under shade conditions was reduced to 14.27% of control trees and this led to a significant reduction in the relative growth rates of all the organs surveyed.

Propagation of Hazelnut Stem Cuttings Using Agrobacterium rhizogenes

Hazelnut (Corylus avellana L.) softwood cuttings of the cultivars Ennis and Casina were propagated under mist during June and July 1987 and 1988. Rooting of stem cuttings was stimulated by both Agrobacterium and IBA treatment; however, IBA caused nearly complete bud abscission. Better rooting and bud retention were observed in `Casina' than in `Ennis' in 1988. Bud retention on Agrobacterium -inoculated cuttings improved as the cuttings approached the semi-hardwood stage. Six months after transplanting, Agrobacterium -inoculated hazelnut cuttings had an extensive root system, characteristic of hairy root. Although the mechanism remains unclear, strains of Agrobacterium rhizogenes are effective rooting agents in hazelnut and may cause less bud abscission than IBA. Chemical name used: 1 H -indole-3-butyric acid (IBA).

SHOOT POSITION, IBA AND AGROBACTERIUM RHIZOGENES INFLUENCE PROPAGATION OF HAZELNUT, CORYLUS AVELLANA

Propagation of Corylus avellana stem cuttings may be limited by either root initiation or bud abscission. We divided juvenile shoots of 3 varieties growing in layering beds in mid-July into 4 or 5 3-node cuttings with leaves at the upper two nodes, except that terminal cuttings had one expanded leaf. Cuttings were treated with 5 mM IBA in 50% EtOH, a mixture of A. rhizogenes strains A7 + 22 or left untreated. IBA and bacteria stimulated rooting of cuttings from all shoot positions. Rooting of the terminal cuttings (&lt;50%) was less than that of the sub-terminal cuttings (&gt;80%). Bud retention was &lt;50% on terminal cuttings, nearly 100% on sub-terminal cuttings. Using juvenile stock plants of various varieties, sub-terminal cuttings treated with Agrobacterium or 5 mM IBA may yield 70-90% cuttings with both roots and buds, Agravitropic roots, characteristic of genetic transformation, were observed on Agrobacterium-treated cuttings. Dot blots probed for TL-DNA were negative, however.

SHOOT POSITION, IBA AND AGROBACTERIUM RHIZOGENES INFLUENCE PROPAGATION OF HAZELNUT, CORYLUS AVELLANA

Propagation of Corylus avellana stem cuttings may be limited by either root initiation or bud abscission. We divided juvenile shoots of 3 varieties growing in layering beds in mid-July into 4 or 5 3-node cuttings with leaves at the upper two nodes, except that terminal cuttings had one expanded leaf. Cuttings were treated with 5 mM IBA in 50% EtOH, a mixture of A. rhizogenes strains A7 + 22 or left untreated. IBA and bacteria stimulated rooting of cuttings from all shoot positions. Rooting of the terminal cuttings (&lt;50%) was less than that of the sub-terminal cuttings (&gt;80%). Bud retention was &lt;50% on terminal cuttings, nearly 100% on sub-terminal cuttings. Using juvenile stock plants of various varieties, sub-terminal cuttings treated with Agrobacterium or 5 mM IBA may yield 70-90% cuttings with both roots and buds, Agravitropic roots, characteristic of genetic transformation, were observed on Agrobacterium-treated cuttings. Dot blots probed for TL-DNA were negative, however.

Inflorescence Bud Retetion In `Kerman' Pistachio: Effects Of Defruting Date And Branch Size

Alternate bearing in pistachio (Pistacia vera L.) is correlated with crop load; a heavy crop on l-year-old wood appears to cause abscission of inflorescence buds on current wood. Defruiting heavily bearing trees before or during the period of nut growth stopped inflorescence bud loss. This relationship between crop and bud loss was affected by the fruiting status of neighboring shoots. Large defruited branches (&gt; 5.5cm diameter). in fruiting trees had bud retention values (50% to 65%) equivalent to fully defruited control trees, but smaller branches showed reduced bud retention levels. Bud retention was increased 2- to 6-fold in small branches when neighboring branches were defruited. Nitrogen concentration of leaves in late August was positively correlated with the final bud retention percentage and inversely correlated with defruiting date.