scholarly journals 682 New Perspectives on the Influence of Mid-season Environment on Apple Fruit Characteristics

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 516C-516
Author(s):  
D.S. Tustin ◽  
T. Fulton ◽  
H. Brown
Keyword(s):  
Cell Division ◽  
Fruit Development ◽  
Climatic Variability ◽  
Fruit Size ◽  
Cortical Cell ◽  
Dry Weight ◽  
Apple Fruit ◽  
Major Influence ◽  
Controlled Environment ◽  
Crop Load

Growth of apple fruit can be described as an initial exponential phase lasting the 40+ days of fruit cell division followed by a more-or-less linear phase where growth is by cell expansion. Temperature is a major influence on fruit growth rate during the cell division phase, thereby affecting fruit size at maturity. However it is generally thought that temperature has less-direct impact on fruit development during the fruit expansion phase. Our observations of apple growth among regions and seasons of considerable climatic variability led us to speculate that temperature may impact directly on fruit development during fruit expansion but that responses may be interactive with carbon balance (crop load) influences. Controlled environment studies are being used to examine this hypothesis. Potted `Royal Gala' trees set to three levels of crop (one fruit per 250, 500, or 1000 cm2 leaf area) were grown from 56 to 112 DAFB in day/night temperature regimes of 18/6, 24/12, and 30/18 °C. All trees grew in field conditions prior to and following the controlled environment treatments. Treatments were harvested when 20% to 25% of fruit on trees showed the visual indicators used commercially to indicate harvest maturity. Fruit were evaluated using attributes that determine quality and that may have implications for fruit post harvest behaviour. Temperature and crop load influences on time to maturity, fruit fresh and dry weight, fruit DM content, fruit firmness, fruit airspace content and estimated fruit cortical cell size will be presented and implications discussed.

scholarly journals Benzyladenine Effects on Cell Division and Cell Size during Apple Fruit Thinning

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 852F-852
Author(s):  
Paul T. Wismer ◽  
J.T.A. Proctor ◽  
D.C. Elfving
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Control Cell ◽  
Fruit Size ◽  
Cortical Cell ◽  
Dry Weight ◽  
Apple Fruit ◽  
Naphthaleneacetic Acid ◽  
Fruit Thinning ◽  
Control Cell Division

Benzyladenine (BA), carbaryl (CB), daminozide (DM), and naphthaleneacetic acid (NAA) were applied postbloom, as fruitlet thinning agents, to mature `Empire' apple trees. Although fruit set and yield were similar for BA, NAA, and CB, BA-treated fruit were larger, indicating BA increased fruit size beyond the effect attributable to thinning. BA applied at 100 mg·liter–1 increased the rate of cell layer formation in the fruit cortex, indicating that BA stimulated cortical cell division. The maximum rate of cell division occurred 10 to 14 days after full bloom (DAFB) when fruit relative growth rate and density reached a maximum and percent dry weight reached a minimum. Cell size in BA-treated fruit was similar to the control. Cell division ended by 35 DAFB in the control and BA-treated fruit when percent dry weight and dry weight began to increase rapidly and fruit density changed from a rapid to a slower rate of decreased density. These data support the hypothesis that BA-induced fruit size increases in `Empire' apple result largely from greater numbers of cells in the fruit cortex, whereas the fruit size increase due to NAA or CB is a consequence of larger cell size.

scholarly journals 683 Contributions of Early Season Environment and Crop Load to Apple Fruit Development

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 516D-516
Author(s):  
C.J. Stanley ◽  
D.S. Tustin
Keyword(s):  
Cell Division ◽  
Fruit Size ◽  
Cell Number ◽  
Apple Fruit ◽  
Fruit Weight ◽  
Full Bloom ◽  
Crop Load ◽  
Early Season ◽  
Growth Partitioning ◽  
Load Conditions

Many factors contribute to final apple fruit size. Researchers have studied these factors and have developed models, some very complex. Results from many New Zealand regions over several years suggest that early season temperature along with crop load are the key factors driving final fruit size. Accumulated growing degree days from full bloom to 50 days after full bloom (DAFB), accounted for 90% of the variance in fruit weight of `Royal Gala' apples at 50 DAFB under nonlimiting low-crop-load conditions. In turn, fruit weight at 50 DAFB accounted for 90% of the variance in final fruit size at harvest under the low-crop-load conditions. We hypothesise that a potential maximum fruit size is set by 50 DAFB, determined by total fruit cell number, resulting from a temperature-responsive cell division phase. Under conditions of no limitations after the cell division phase, we suggest that all cells would expand to their optimum size to provide the maximum fruit size achievable for that cell number. Factors which affect growth partitioning among fruits, e.g., higher crop loads, would reduce final fruit size, for any given cell number, when grown in the same environment. In Oct. 1999, four different crop loads were established at full bloom on `Royal Gala' trees (M9 rootstock) in four climatically different regions. In Hawkes Bay, similar crop loads were established at 50 DAFB on additional trees. Hourly temperatures were recorded over the season. Fruit size was measured at 50 DAFB and fruit will be harvested in Feb. 2000. These data should provide fresh insight and discussion into the respective roles of temperature and competition during the cell division fruit growth phase on apple fruit size.

DEVELOPMENTAL STUDIES OF THE APPLE FRUIT IN THE VARIETIES McINTOSH RED AND WAGENER: II. AN ANALYSIS OF DEVELOPMENT

1941 ◽  
Vol 19c (10) ◽  
pp. 371-382 ◽  
Author(s):  
Mary MacArthur ◽  
R. H. Wetmore
Keyword(s):  
Cell Division ◽  
Cell Size ◽  
Fruit Size ◽  
Apple Fruit ◽  
Vascular Bundles ◽  
Developmental Studies ◽  
Cell Enlargement ◽  
Ground Tissue ◽  
Fundamental Pattern

Growth in the various tissues of the fruit of a McIntosh Red and a Wagener tree, both self-pollinated, is compared. For several days succeeding pollination no increase in fruit size is apparent. Fertilization is followed by general cell division and cell enlargement. The period of cell division varies with the tissue and with the variety. Final cell size is reached first by the cells of those tissues near the centre of the apple. Impressed upon the fundamental pattern of growth is the localized activity of the primary vascular bundles, the cambia of which add cells to the ground tissue. Angulation in the Wagener is accentuated by this activity. With the exception of cells of the epidermis, final cell size is approximately equal in comparable regions of the two varieties. Differences in regional extent are due to differences in numbers of cells in that region.

scholarly journals Optimizing Fruit-Thinning Strategies in Peach (Prunus persica) Production

Horticulturae ◽  
2020 ◽  
Vol 6 (3) ◽  
pp. 41 ◽  
Author(s):  
Mary Sutton ◽  
John Doyle ◽  
Dario Chavez ◽  
Anish Malladi
Keyword(s):  
Fruit Development ◽  
Fruit Size ◽  
Fruit Weight ◽  
Load Management ◽  
Growth Responses ◽  
Crop Load ◽  
Fruit Number ◽  
Fruit Thinning ◽  
Adverse Weather ◽  
One Year

Fruit size is a highly valued commercial trait in peach. Competition among fruit and among other sinks on a tree reduces potential growth rate of the fruit. Hence, crop-load management strategies such as thinning (removal of flowers or fruit) are often practiced by growers to optimize fruit size. Thinning can be performed at bloom or during early fruit development and at different intensities to optimize fruit growth responses. Responses to thinning may be cultivar and location specific. The objective of the current study was to fine-tune thinning strategies in the southeastern United States, a major peach producing region. Timing and intensity of thinning were evaluated across multiple cultivars over three years. Thinning at bloom or at 21 d after full bloom (DAFB) improved fruit size in comparison to unthinned trees in ‘Cary Mac’ and ‘July Prince’, respectively, in one year. Bloom-thinning reduced fruit yield (kg per tree) in the above cultivars in one year, suggesting that flower thinning alone may not be a viable option in this region. Intensity of thinning, evaluated as spacings of 15 cm and 20 cm between fruit, did not differentially affect fruit weight or yield. However, fruit diameter decreased quadratically with increasing fruit number per tree in ‘Cary Mac’, ‘July Prince’ and ‘Summer Flame’. Similarly, fruit weight decreased quadratically in response to increase in fruit number per tree in ‘Cary Mac’ and ‘July Prince’. Further, yield-per-tree decreased with increasing fruit size in ‘Cary Mac’ and ‘July Prince’. Importantly, these relationships were cultivar specific. Together, the data suggest that achieving a target fruit number per tree is an effective strategy for crop-load management to optimize fruit size in southeastern peach production. The target fruit number per tree may potentially be achieved through a combination of flower and fruit-thinning during early fruit development. Such an approach may provide flexibility in crop-load management in relation to adverse weather events.

scholarly journals Flower Bud Density Affects Vegetative and Fruit Development in Field-grown Southern Highbush Blueberry

HortScience ◽  
1999 ◽  
Vol 34 (4) ◽  
pp. 607-610 ◽  
Author(s):  
B.E. Maust ◽  
J.G. Williamson ◽  
R.L. Darnell
Keyword(s):  
Leaf Area ◽  
Fruit Development ◽  
Fruit Size ◽  
Dry Weight ◽  
Vaccinium Corymbosum ◽  
Soluble Solids ◽  
Highbush Blueberry ◽  
Flower Buds ◽  
Flower Bud ◽  
Southern Highbush

Floral budbreak and fruit set in many southern highbush blueberry (SHB) cultivars (hybrids of Vaccinium corymbosum L. with other species of Vaccinium) begin prior to vegetative budbreak. Experiments were conducted with two SHB cultivars, `Misty' and `Sharpblue', to test the hypothesis that initial flower bud density (flower buds/m cane length) affects vegetative budbreak and shoot development, which in turn affect fruit development. Flower bud density of field-grown plants was adjusted in two nonconsecutive years by removing none, one-third, or two-thirds of the flower buds during dormancy. Vegetative budbreak, new shoot dry weight, leaf area, and leaf area: fruit ratios decreased with increasing flower bud density in both cultivars. Average fruit fresh weight and fruit soluble solids decreased in both cultivars, and fruit ripening was delayed in `Misty' as leaf area: fruit ratios decreased. This study indicates that because of the inverse relationship between flower bud density and canopy establishment, decreasing the density of flower buds in SHB will increase fruit size and quality and hasten ripening.

scholarly journals (463) Grapefruit Crop Load Affects Net Gas Exchange of Leaves, Tree Growth, and Fruit Quality

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1048A-1048
Author(s):  
Kuo-Tan Li ◽  
Jim Syvertsen ◽  
Jill Dunlop
Keyword(s):  
Fruit Quality ◽  
Fruit Size ◽  
Dry Weight ◽  
Fruit Shape ◽  
Solid Content ◽  
Soluble Solid Content ◽  
Citrus Paradisi ◽  
Fruit Removal ◽  
Crop Load ◽  
Four Levels

Effects of crop load on leaf characteristics, shoot growth, fruit shape, fruit quality, and return bloom were investigated in 13-year-old `Ruby Red' grapefruit (Citrus paradisi Macf.) on `Swingle' citrumleo rootstock. Trees were hand thinned in June 2003 and 2004 at the end of physiological fruit drop to establish three to four levels of crop load ranging from normal (high crop load without thinning) to extremely low (near 90% fruit removal). Leaves on high crop load trees had higher net assimilation of CO2 (ACO2) than those on low crop load trees. Crop load enhancement of ACO2 continued until harvest. In 2004, however, the effects were diminished in October just prior to the beginning of the harvest season, after leaf and fruit loss from three consecutive hurricanes. There was no difference in leaf dry weight per leaf area and leaf nitrogen among treatments. Nonfruiting branches of high crop load trees produced fewer, but longer, summer flushes than those of low crop load trees. Fruiting branches generally produced few summer flushes with similar shoot lengths among treatments. High crop load trees developed a greater percentage of vegetative shoots, whereas low crop load trees developed more inflorescences. Crop load adjustments did not affect fruit size and total soluble solid content, but low crop load trees produced a higher percentage of irregular shape (sheepnosed) fruit with high acidity.

Influence of pre- and post-harvest treatments on bitter pit of Granny Smith apples in the Goulburn Valley

1968 ◽  
Vol 8 (31) ◽  
pp. 244
Author(s):  
BK Taylor ◽  
den Ende B van
Keyword(s):  
Fruit Size ◽  
Calcium Nitrate ◽  
Dry Weight ◽  
Calcium Deficiency ◽  
Apple Fruit ◽  
Residual Effects ◽  
Foliar Sprays ◽  
Efficient Control ◽  
Calcium Magnesium ◽  
Calcium Status

Methods of controlling storage pit of Granny Smith apples were studied in the Goulburn Valley from 1960 to 1966. Foliar sprays of calcium nitrate reduced pit but boron sprays did not. Most efficient control was achieved with three or more sprays applied between December and March. Residual effects from such sprays were not observed the next season. Foliar sprays of calcium nitrate increased the concentration of calcium in spur leaves but not in fruit tissues. Dipping unsprayed fruit after harvest in solutions of calcium chloride or calcium nitrate, or wrapping fruit in paper sheets impregnated with calcium salts, gave negative or inconsistent results. Such treatments did not usually alter the concentrations or amounts of calcium, magnesium, or potassium in fruit tissues. The concentration of calcium in all fruit parts declined as fruit size (dry weight) increased. Since pit severity also increased with increasing fruit size, the calcium status of the fruit, fruit size, and pit incidence were closely related. The concentration of calcium in mesocarp + endocarp showed the highest negative correlation with pit severity of any of the fruit parts, and this tissue was therefore the best indicator of the calcium status and pit susceptibility of the fruit. It is concluded that pit is not due to an inbalance between calcium, magnesium, and potassium in the fruit but that it is merely the syndrome of calcium deficiency in the apple fruit. No differences were found in flavour characteristics between pitted and sound fruit.

The effect of irrigation and crop load on stem water potential and apple fruit size

1997 ◽  
Vol 72 (5) ◽  
pp. 765-771 ◽  
Author(s):  
A. Naor ◽  
I. Klein ◽  
I. Doron ◽  
Y. Gal ◽  
Z. Ben-David ◽  
...  
Keyword(s):  
Water Potential ◽  
Fruit Size ◽  
Apple Fruit ◽  
Stem Water Potential ◽  
Crop Load ◽  
Stem Water

Morphological, anatomical, and physiological changes in the developing fruit of the Valencia orange, Citrus sinensis (L) Osbeck

1958 ◽  
Vol 6 (1) ◽  
pp. 1 ◽  
Author(s):  
JM Bain
Keyword(s):  
Cell Division ◽  
Fruit Size ◽  
Dry Weight ◽  
Soluble Solids ◽  
Physiological Changes ◽  
Maximum Width ◽  
Protein Nitrogen ◽  
Growing Seasons ◽  
South Wales ◽  
Cell Layers

Measurements of fruit radius and peel and pulp width, as well as determinations of fresh weight, dry weight, moisture content total and protein nitrogen content, and respiration rate were made throughout two growing seasons on Valencia oranges from the Gosford district of New South Wales. Soluble solids, sugar, and acid were also determined in the juice. Anatomical changes during development were investigated throughout one season. Development could be divided into three stages, corresponding with changes in growth rate and coinciding on a calendar basis in both seasons. Stage I varied in length according to the date of the blossom, but was completed by mid December. This was the cell division stage; by mid December cell division was completed in all tissues except the outermost cell layers. Increase in fruit size at this stage was mainly due to increased peel thickness. Stage 11, a period of very rapid growth from mid December to mid July, was the critical period for growth and was distinguished as the cell enlargement period, rapid morphological and physiological changes occurring in the absence of cell division. The growth of the pulp was responsible for most of the increase in fruit size during Stage 11; the peel reached a maximum width early in this stage and then became thinner with very little subsequent change in thickness as the pulp continued to increase in size. Stage 111, the maturation period, lasted from mid July until the fruit was ripe, or approximately 7 months. Fruit continued to grow for as long as it was left on the tree but at a very reduced rate compared with Stage 11. Ripening occurred during Stage 111.

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