Bud-, flower- and fruit-density in stone fruits

In 164 varieties of five stone fruit species, counts of flower buds, flowers and fruits set have been performed, regularly, between 1982 and 2002. The critical number and sample size has been determined for the purpose to estimate the yielding potential of peach plantations. For a rapid test, 10 shoots per variety are recommended. In sour cherry and peach varieties, the number and ratio of leaf and flower buds has been assessed on bearing shoots of different length. The typical flower bud density of 129 peach varieties varies, as a rule, between 0.13 and 1.10 bud/cm. Three groups of flower-bud-densities could be distinguished: low (0-0.40 bud/cm), intermediate (0.41-0.60 bud/cm), high (more than 0.60 bud/cm). About 62% of varieties belong to the intermediate group. Negative correlation has been found between flower density and relative fruit set, whereas positive correlation between flower density and fruit yield. The results are utilised in the description and choice of varieties, moreover, in choosing of optimal pruning policies. Varieties of high flower bud densities are recommended to be preferred for growing sites with frequent late frosts. Abundantly yielding varieties of low vegetative vigour are to be pruned more severely than those characterised by low yields, vigorous growth and low flower density. Sour cherry varieties, which are inclined to grow "whips" ought to be stimulated to grow longer shoots (40-50 cm per year), than varieties woid of that tendency (30-40 cm).

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Different Summer and Autumn Water Deficit Affect the Floral Differentiation and Flower Bud Growth in Apricot (Prunus armeniaca L.)

Agronomy ◽

10.3390/agronomy10060914 ◽

2020 ◽

Vol 10 (6) ◽

pp. 914

Author(s):

Susanna Bartolini ◽

Ermes Lo Piccolo ◽

Damiano Remorini

Keyword(s):

Water Deficit ◽

Water Availability ◽

Water Status ◽

Prunus Armeniaca ◽

Stem Water Potential ◽

Flower Buds ◽

Flower Bud ◽

Fruit Species ◽

Floral Differentiation ◽

Bud Initiation

In deciduous fruit species, floral bud initiation, differentiation and organogenesis take place during the summer–autumn season that precedes anthesis. Among factors able to modify the regularity of these processes, water availability represents a crucial aspect. This investigation aimed to assess the influence of different summer and autumn water deficit and re-watering treatments on floral morphogenesis, xylem vessel differentiation and quality of flower buds. Trials were carried out on two-year-old potted apricot trees (cv. ‘Portici’) which were submitted to different regimes: (i) fully irrigated plants; (ii) stressed plants in June (S1), July (S2) and October (S3) followed to re-watering. Midday stem water potential was used to determine water status, and leaf gas exchanges were measured during trials. Histological analyses on floral differentiation, xylem progression within flower buds and biological observations were carried out. Both summer water stress periods affected the floral differentiation leading to a temporary shutdown. The S1 trees were able to recover the development of meristematic apices while S2 had a strong delay. All drought treatments caused a slower xylem progression, variations in bud size, blooming entity and flower anomalies. Results particularly highlights the importance of water availability also in early autumn.

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Flower Bud Stage and Chill Hours Influence the Activity of GA3 Applied to Rabbiteye Blueberry

HortScience ◽

10.21273/hortsci.27.4.316 ◽

1992 ◽

Vol 27 (4) ◽

pp. 316-318 ◽

Cited By ~ 5

Author(s):

D.S. NeSmith ◽

Gerard Krewer

Keyword(s):

Gibberellic Acid ◽

Growth Regulator ◽

Flower Development ◽

Fruit Set ◽

Developmental Stages ◽

Single Application ◽

Flower Buds ◽

Flower Bud ◽

Vaccinium Ashei

Individual flower clusters of `Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) were treated with 300 ppm GA at several flower bud stages to determine the activity of the growth regulator in promoting fruit set. Applications were made one time only at a specified stage of flower development, or once followed by a second application. A single application of GA when flower buds had elongated but corollas had not expanded (stage 5) led to the largest increase in fruit set. Two applications of GA, 10 to 18 days apart, increased fruit set compared with a single application at flower developmental stages other than stage 5. Fruit set promoted by a single spray of GA imposed on fully expanded corollas (stage 6) decreased with increasing number of chill hours (350, 520, 760, or 1150). Chemical names used: gibberellic acid (GA).

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Hydrogen Cyanamide Stimulates Early Foliation of `Misty' Southern Highbush Blueberry

HortScience ◽

10.21273/hortsci.32.3.537c ◽

1997 ◽

Vol 32 (3) ◽

pp. 537C-537

Author(s):

J.G. Williamson ◽

R.L. Darnell

Keyword(s):

Vegetative Growth ◽

Fruit Set ◽

Small Diameter ◽

Highbush Blueberry ◽

Full Bloom ◽

Flower Buds ◽

Flower Bud ◽

Hydrogen Cyanamide ◽

Southern Highbush ◽

Chilling Treatment

Two-year-old, container-grown `Misty' southern highbush blueberry plants were sprayed to drip with two concentrations of hydrogen cyanamide (HCN) (20.4 g·L–1 and 10.2 g·L–1) after exposure to 0, 150, or 300 hr of continuous chilling at 5.6°C. All plants were sprayed immediately after chilling and placed in a greenhouse for several weeks. The plants were moved outdoors during flowering to increase cross-pollination from nearby `Sharpblue' blueberry plants. HCN sprays killed some of the more advanced flower buds on shoot terminals and on small-diameter wood from the previous spring growth flush. Significantly greater flower bud mortality occurred for the 20.4 g·L–1 HCN sprays than for the 10.2 g·L–1 sprays. Flower buds subjected to 0 hr of chilling were more susceptible to spray burn than flower buds receiving 150 or 300 hr of chilling. Very little flower bud death occurred with the 10.2 g·L–1 HCN rate on plants receiving 300 hr of chilling. Vegetative budbreak was advanced for both HCN treatments compared to controls, regardless of chilling treatment. HCN-treated plants were heavily foliated at full bloom, while non-treated plants had very few to no leaves during bloom. HCN may be useful for stimulating vegetative growth in some southern highbush blueberry cultivars that suffer from poor foliation during flowering and fruit set.

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Influence of Blossom and Fruit Thinning on Peach Flower Bud Tolerance to an Early Spring Freeze

HortScience ◽

10.21273/hortsci.29.3.146 ◽

1994 ◽

Vol 29 (3) ◽

pp. 146-148 ◽

Cited By ~ 12

Author(s):

Ross E. Byers ◽

R.P. Marini

Keyword(s):

Prunus Persica ◽

Fruit Set ◽

Unit Length ◽

Early Spring ◽

Late Winter ◽

Flower Buds ◽

Flower Bud ◽

Cross Sectional ◽

Fruit Thinning ◽

Crop Density

Peach trees [Prunus persica (L.) BatSch.] blossom-thinned by hand were overthinned due to poor fruit set of the remaining flowers; however, their yield was equivalent to trees hand-thinned 38 or 68 days after full bloom (AFB). Blossom-thinned trees had three times the number of flower buds per unit length of shoot and had more than two times the percentage of live buds after a March freeze that had occurred at early bud swell the following spring. Blossom-thinned trees were more vigorous; their pruning weight increased 45%. For blossom-thinned trees, the number of flowers per square centimeter limb cross-sectional area (CSA) was two times that of hand-thinned trees and four times that of the control trees for the next season. Fruit set of blossom-thinned trees was increased four times. Flower buds on the bottom half of shoots on blossom-thinned trees were more cold tolerant than when hand-thinned 68 days AFB. Fruit set per square centimeter limb CSA was 400% greater the following year on blossom-thinned trees compared to controls. Removing strong upright shoots on scaffold limbs and at renewal points early in their development decreased dormant pruning time and weight and increased red pigmentation of fruit at the second picking. The number of flower buds per unit shoot length and percent live buds after the spring freeze were negatively related to crop density the previous season for trees that had been hand-thinned to varying crop densities at 48 days AFB. According to these results, blossom thinning and fruit thinning to moderate crop densities can influence the cold tolerance of peach flower buds in late winter.

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Leaf absorption, withdrawal and remobilization of autumn-applied urea-N in apple

Canadian Journal of Plant Science ◽

10.4141/p02-114 ◽

2004 ◽

Vol 84 (1) ◽

pp. 259-264 ◽

Cited By ~ 3

Author(s):

S. Guak ◽

D. Neilsen ◽

P. Millard ◽

N. E. Looney

Keyword(s):

Malus Domestica ◽

Low Temperatures ◽

Fruit Set ◽

Urea Solution ◽

Flower Buds ◽

Flower Bud ◽

Flower Opening ◽

Total N ◽

Bud Growth ◽

Flower Quality

Six-year-old well-nourished Jonagold/M9 apple (Malus domestica) trees were sprayed 7 d after harvest with a 2% urea solution enriched with 9.9% atom 15N. Through 3 d of the absorption period, leaves absorbed 19.2% of the intercepted urea 15N. This low absorption could be in part due to unfavourable conditions, i.e., low temperatures (daily mean ≈5°C) and windy conditions following treatment. During leaf senescence, 48% of the urea 15N absorbed was withdrawn from leaves and most of that (95%) remained in the treated branch section. Of this portion, 65% of the urea 15N was found in dormant bark, 29% in wood, and 6% in flower buds. In the following spring, 46% of the stored urea 15N was remobilized for growth of the flower buds when sampled at the “pink” stage of bud development. This accounted for 3.8% of total N in these tissues. This contribution did not influence flower quality, estimated by the length of the period between flower opening and petal fall and the level of fruit set. Key words: Malus × domestica, urea-15N, flower bud growth, fruit set

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322 WHY DOES SOUR CHERRY (Prunus cerasus) PRODUCE SO MANY MORE FLOWERS THAN FRUITS?

HortScience ◽

10.21273/hortsci.29.5.476e ◽

1994 ◽

Vol 29 (5) ◽

pp. 476e-476

Author(s):

A. Kahn ◽

A.F. Iezzoni ◽

S. Kalisz ◽

CA. Mulinix ◽

V. Delasalle

Keyword(s):

Fruit Set ◽

Germplasm Collection ◽

Sour Cherry ◽

Pollinator Attraction ◽

Cross Sectional ◽

Hand Pollination ◽

Flower Density ◽

Zygotic Selection ◽

Maternal Resources ◽

Flower Display

The number of flowers produced by sour cherry greatly exceeds the number of fruits developed. Two hypotheses to explain this disparity were investigated: (1) pollen may be limiting, and (2) a large flower display is important for pollinator attraction. Self-incompatibility, which is common in sour cherry, was considered. Fruit set, floral morphology, and flower density were measured on 18 sour cherry selections, both self-compatible and self-incompatible (SI), in the MSU sour cherry germplasm collection following open- and bulk-pollination. Although supplemental hand pollination resulted in a significant increase in fruit set, the final fruit set was still low (18% vs 14%) indicating that lack of pollination alone was insufficient to account for the low fruit set. The SI selections had significantly larger flower cups, pistil/petal size ratio, and more flowers/branch cross-sectional area suggesting that flower display may have an increased role in pollinator attraction in the SI selections. These results will be discussed in relation to 2 additional hypotheses: insufficient maternal resources and genetic factors resulting in pre- or post-zygotic selection.

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(93) Vegetative and Flower Bud Development, and Fruit Set of Low-chill Peach Cultivars in North-central, Central, and Southwest Florida

HortScience ◽

10.21273/hortsci.41.4.1029a ◽

2006 ◽

Vol 41 (4) ◽

pp. 1029A-1029

Author(s):

Todd Wert ◽

Jeffrey G. Williamson ◽

Robert E. Rouse

Keyword(s):

Fruit Set ◽

Average Length ◽

Flower Buds ◽

Flower Bud ◽

North Central ◽

Bud Development ◽

Central Florida ◽

Southwest Florida ◽

Vegetative Buds ◽

Flower Bud Development

Four low-chill peach cultivars were evaluated at three locations in Florida for vegetative and reproductive bud development and fruit set. Twenty trees (five each of `Flordaprince', `Tropicbeauty', `UFgold', and `Flordaglo') were planted at each site in Feb. 2002. Prior to budbreak in Spring 2004 and 2005, three shoots per tree of average length and diameter were selected at a height between 1.5–2.0 m and the numbers of vegetative and flower buds per node were recorded for each shoot. No consistent pattern for the number of vegetative buds per node was observed among cultivars and locations, or across years. However, 'Tropicbeauty' tended to have fewer vegetative buds per node than `Flordaprince' during both seasons, although not at all locations. Overall, the number of flower buds per node was greater for north-central Florida than for central or southwest Florida. There were no consistent tends over years and among locations for the ranked order of flower buds per node by cultivar. The percentage of nodes without flower or vegetative buds (blind nodes) was generally greatest for `Tropicbeauty' at most locations during both years. During 2005, the percentage of blind nodes was greater in central and southwest Florida than in north-central Florida. Overall, fruit set was similar between the central and north-central Florida locations. Fruit set tended to be higher for `UFGold' and `Flordaglo' than for `Flordaprince' or `Tropicbeauty'.

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Studying on the frost damage of some peach and nectarine varieties

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/22/3179 ◽

2006 ◽

pp. 13-15

Author(s):

Mária Dani ◽

Sándor Thurzó ◽

József Racskó ◽

Gábor Drén

Keyword(s):

Frost Damage ◽

Frost Tolerance ◽

Climatic Conditions ◽

Yield Stability ◽

Stone Fruit ◽

Stone Fruits ◽

Flower Bud ◽

Spring Frost ◽

Fruit Species ◽

Second Year

To be able to grow stone fruit species, the peach and the nectarine varieties, yield stability is very relevant. However, the climate is suitable in Hungary for growing stone fruits. We have to calculate with damage. Important winter damage and spring frost damage occur in every second year on the Great Pplains. To reveal the frost tolerance of cultivars and to clarify the differences among growing areas is the most important point of peach and nectarine production.We, made our experiments in the winter of 2005 (January-February), at Pallag, Zsombó, Siófok, Sóskút and Szatymaz. These former places are determinant in peach and nectarine growing in Hungarian respects.In our experiments we analyzed 10-10 fruit shoot from 82 varieties, and we measured the frost damage and the flower bud density.The minimum and the maximum frost damage values (%) at the different growing places were 7.6-38.7 at Siófok, 6.5-31.3 at Sóskút, 34.3-100 at Szatymaz, 83.7-99.6 at Pallag and 51.9-99.6 at Zsombó. There were expressive differences between the same cultivars depending on the growing area.The frost damage of „Suncrest” variety was 7.6% at Siófok, 8.2% at Sóskút but it was 69.8% at Szatymaz. The „Maystar” variety had 17.6% at Siófok, 12.4% at Sóskút and 87.2% frost damage at Szatymaz. In case of „Redhaven” variety the frost damage values were 16.8% at Sóskút, 54.6% at Szatymaz. We collected fruit shoots from three different heights in case of „Cresthaven” variety. In case of 1 meter height the frost damage was 74.6%, at 2 meter height 44.7%, and 25.2% at 3 meter.We experienced also big differences in flower bud density (flower bud/10 cm) of varieties. The following cultivars had the highest flower bud density (6-7 bud/10 cm): „Suncrest”, „Meystar, „Maria Luisa” and the „Maria Bianca”, „Redhaven”, „Michellini” had the lowest flower bud density (2-3 bud/10 cm).After our experiments we established that there were very expressive differences among the frost damage of peach and nectarine varieties from different climatic conditions and there are also big variance between the frost damage values of those fruit shoots, what were collected from different heights, but from the same variety. It conspicuous very good among our items, that difference of the flower bud density is very big among the varieties.To be able to grow peach and nectarine successfully, the suitable variety (low frost damage value, high flower bud density) and the suitable growing are is determinant.

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Various Freezing Strategies of Flower-bud Hardiness in Prunus

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.119.3.584 ◽

1994 ◽

Vol 119 (3) ◽

pp. 584-588 ◽

Cited By ~ 4

Author(s):

Sorkel A. Kadir ◽

Edward L. Proebsting

Keyword(s):

Prunus Persica ◽

Prunus Dulcis ◽

Prunus Serotina ◽

Flower Buds ◽

Flower Bud ◽

Intermediate Group ◽

Prunus Salicina ◽

Moderate Rate ◽

Large Flower ◽

Prunus Davidiana

Flower buds of 20 Prunus species showed quite different strategies to cope with low temperatures. Buds of most species deep supercooled. The two hardiest species, both from the subgenus Padus (P. padus L. and P. virginiana L.), did not supercool and survived -33C with no bud kill. Prunus serotina J.F. Ehrh., also in Padus, did supercool. Prunus nigra Ait., P. americana Marsh, P. fruticosa Pall., and P. besseyi L.H. Bailey had a low minimum hardiness level (MHL), small buds, and a low water content. Exotherms were no longer detectable from the buds of these species after 2 days at -7C and some buds survived -33C. Prunus triloba Lindl. and P. japonica Thunb. were similar to that group, but no buds survived -33C. Prunus davidiana (Carriere) Franch., P. avium L., and P. domestica L. had a relatively high MHL but hardened rapidly when the buds were frozen. Prunus persica (L.) Batsch., P. subhirtella Miq., P. dulcis (Mill) D. A. Webb, and P. emarginata (Dougl. ex Hook) Walp. deep supercooled, had large flower buds and a high MHL, and were killed in the Dec. 1990 freeze. Prunus salicina Lindl., P. hortulana L.H. Bailey, P. armeniaca L., and P. tomentosa Thunb. were in an intermediate group with a moderately low MHL and a moderate rate of hardiness increase while frozen. Prunus dulcis and P. davidiana had a low chilling requirement and bloomed early, whereas P. virginiana, P. fruticosa, P. nigra, and P. domestica had high chilling requirements and bloomed late.

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Supercooling and Cold Hardiness in Sour Cherry Germplasm: Flower Buds

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.5.0675 ◽

2004 ◽

Vol 129 (5) ◽

pp. 675-681 ◽

Cited By ~ 3

Author(s):

H.M. Mathers

Keyword(s):

Cold Hardiness ◽

Geographic Origin ◽

Principal Component ◽

Sour Cherry ◽

Commercial Production ◽

Flower Buds ◽

Flower Bud ◽

Floral Tissue ◽

Annual Minimum Temperature ◽

Freezing Temperatures

Flower buds of two sweet cherry (Prunus avium L.), 12 sour cherry (Prunus cerasus L.) and one ground cherry (P. fruticosa Pall.) were collected monthly from Aug. 1990 to Mar. 1991, and subjected to freeze tests to determine the level of cold hardiness. LT50 values (temperatures at which 50% of the flower buds were killed) summed over all months were significantly correlated (r = 0.6844, P ≤ 0.01) to the flower bud low temperature exotherms (LTEs). Correlation of LTEs to LT50 values was highest, r = 0.85, P ≤ 0.01 for the acclimation and midwinter period, November to February collections. During this period the average LT50 occurred before and within 2.5 °C of the LTE, indicating tissue injury before the LTE occurrence. During deacclimation, represented by the March collection, the LT50 began within 2.0 °C, on average, of the LTE, and in 11 of 12 cultivars and seedlings preceded the LTE. In March, the correlation of LTEs to LT50 values was less, r = 0.69, P ≤ 0.05, indicating possible changes flower bud deep supercooling. LTE values were selected as a measure of flower bud hardiness in sour cherry. Exotherms were not detected in the flower buds of all germplasm tested on all evaluation dates, but were the best means of separating selections. While LTE analyses expressed significant differences in November, December, and March at P ≤ 0.01, the LT50 analyses expressed differences only in December and February at P ≤ 0.05. The relationship between ambient temperatures and floral tissue hardiness indicated that November and March are two critical times for flower bud injury. November injury would occur in years when sudden low temperatures occur without sufficient pre-exposure to freezing temperatures. March injury would occur in years when sudden freezing temperatures follow warm days. This type of injury would be most pronounced in southern genotypes. Spring freeze injury could be significantly reduced by the selection of cultivars and seedlings that have delayed deacclimation. Exotherm occurrence and bud volume were correlated (r = 0.95, P ≤ 0.05). In January, when exotherms were least prevalent, they were generally present only in the five cultivars and seedlings with large bud volumes. The LTEs in midwinter, occurred within 3 °C of the reported average annual minimum temperature for the northern range of Prunus commercial production (Zone 6). The results of the principal component analysis of flower bud LTEs indicated that other selection criteria as flowering time might have played a more significant role in the hardiness range of sour cherry than simply geographic origin. The first principal component (PC1), which accounted for 77% of the total variance was used to separate among cultivars and seedlings. Selections at the positive end of PC1 had flower buds that were more cold susceptible than selections at the negative end of PC. This concurs with other research showing that flower bud hardiness is related more to commercial range (i.e., the range of commercial production) than to geographic distribution.

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