scholarly journals Apple Fruit Removal and Limb Girdling Affect Fruit and Leaf Characteristics

1994 ◽  
Vol 119 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Ido Schechter ◽  
J.T.A. Proctor ◽  
D.C. Elfving
Keyword(s):  
Feedback Inhibition ◽  
Dry Weight ◽  
Stomatal Resistance ◽  
Apple Fruit ◽  
Sink Strength ◽  
Fruit Removal ◽  
Cross Sectional ◽  
Crop Load ◽  
Dry Matter Concentration ◽  
Mature Apple

Mature apple trees (Malus domestica Borkh.) were studied in 1989 and 1990 to explore the effect of crop load on fruit dry weight (DW), dry-matter concentration (DMC), specific leaf area (SLA), and leaf C exchange, using girdled (G) and nongirdled (NG) limbs. Fruit DW and DMC decreased with heavier fruit loads. Fruit on G limbs had higher fruit DW and DMC than on NG limbs. SLA on NG limbs was unaffected by crop load, but increased dramatically on G limbs with a crop load of less than one fruit per square centimeter limb cross-sectional area. These leaves also had a low photosynthetic rate, high stomatal resistance, and high internal CO2 concentration. The results do not support the concept of feedback inhibition of photosynthesis and demonstrate specific circumstances in which the capacity of sinks to use assimilates was saturated. Exceeding this limit by significantly reducing sink strength resulted in excessive carbohydrate accumulation in leaves. Nutrient levels in leaves on G, nonfruiting limbs were generally lower than for the other treatments.

scholarly journals THE EFFECT OF CROP LOAD ON FRUIT DRY WEIGHT AND DRY WEIGHT CONTENT, SPECIFIC LEAF WEIGHT, AND LEAF CARBON EXCHANGE.

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 625c-625
Author(s):  
Ido Schechter ◽  
J.T.A. Proctor ◽  
D.C. Elfving
Keyword(s):  
Dry Weight ◽  
Stomatal Resistance ◽  
Sink Strength ◽  
Carbon Exchange ◽  
Specific Leaf Weight ◽  
Physical Damage ◽  
Cross Sectional ◽  
Crop Load ◽  
Leaf Weight ◽  
Weight Content

Mature apple trees (Malus domestica Borkh.) were studied in the 1989 and 1990 seasons to explore the effect of differential crop load on fruit dry weight (DW), DW content, specific leaf weight, and leaf carbon exchange, using girdled and non-girdled limbs. Fruit DW and DW content decreased with heavier fruit loads, however, fruit on girdled limbs had higher fruit DW and DW content. Specific leaf weight did not differ in leaves on non-girdled limbs along the crop load gradient, but increased dramatically in leaves on girdled limbs with crop load lighter than one fruit per cm2 cross-sectional area. These leaves also had a low photosynthetic rate, high stomatal resistance, and high internal CO2 concentration. The results suggest a physiological limit for photoassimilate usage by the tree. Exceeding this limit by reducing sink strength resulted in excessive carbohydrate accumulation in leaves, causing physical damage to the photosystem.

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.

scholarly journals 166 Influence of Crop Level on Growth and Quality of `Braeburn' Apple Fruit

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 418E-419
Author(s):  
P.I. Garriz ◽  
G.M. Colavita ◽  
H.L. Alvarez
Keyword(s):  
Fruit Size ◽  
Growing Season ◽  
Apple Fruit ◽  
Full Bloom ◽  
Cross Sectional ◽  
Crop Load ◽  
Commercial Crop ◽  
Source Sink ◽  
Fruit Diameter

Crop load and the genetic biological carrying capacity (source–sink relationships) determine the potential for fruit size development on apple; however, the environment within which the fruit grows attenuates this potential. The effects of different crop loads on the growth pattern and the progress of maturity in apples were evaluated at the Comahue National Univ., Argentina (lat. 38 56'S long 67 59'W), during the 1998–99 growing season. Our experiment was conducted on 6-year-old `Braeburn'/Malling Merton 111 apple (Malus domestica Borkh.) trees spaced 4.0 × 2.3 m and trained to palmette leader. Treatments were 1) light crop load (LC), 2.5 fruit/cm2 trunk cross-sectional area (TCSA), 2) moderate crop load (MC), 6.5 fruit/cm2 TCSA (standard commercial crop load) and 3) high crop load (HC), minimum 8 fruit/cm2 TCSA, no fruit removed from tree. Whole trees were hand-thinned 19 days after full bloom (DAFB). Fruit diameter (FD) was taken at two weekly intervals (n = 24 per date and treatment) and maturity indexes were determined at harvest. Analysis of variance was used and mean separations were computed with Student's t test. From 38 DAFB until harvest, fruit size was significantly reduced (P < 0.01) in the HC trees, indicating that they were source-limited during growth. At 166 DAFB, FD was 7.48, 7.14, and 6.89 cm for the LC, MC and HC treatments, respectively. Adequate carbon was apparently available to support a commercial crop load since no differences were found between LC and MC trees. Crop level influenced flesh firmness; at 173 DAFB, it was significantly lower in HC trees than MC and LC trees (84.33, 92.51, and 91.57 N, respectively). These results suggest some goals of thinning for ensuring sizable `Braeburn' fruit.

scholarly journals Interaction of Root Confinement and Fruiting in Peach

1995 ◽  
Vol 120 (2) ◽  
pp. 228-234 ◽  
Author(s):  
Othmane Mandre ◽  
Mark Rieger ◽  
Stephen C. Myers ◽  
Ray Seversen ◽  
Jean-Luc Regnard
Keyword(s):  
Vegetative Growth ◽  
Feedback Inhibition ◽  
Dry Weight ◽  
Carbohydrate Content ◽  
Fruit Growth ◽  
Total Carbohydrate ◽  
Fruit Removal ◽  
Physiological Signal ◽  
Carbohydrate Levels ◽  
Peach Trees

Fruiting and nonfruiting `Washington' peach trees were grown in 2.4 (small) or 9-liter (large) containers to determine the influence of root confinement and fruiting on vegetative growth, fruit growth and quality, CO, assimilation (A), and carbohydrate content. Shoot length, fruit diameter, A, and leaf carbohydrates were measured weekly. Thirteen weeks after transplanting, trees were divided into roots, shoots, leaves, and fruit for dry weight measurement. The dry weight of all organs except fruit was reduced by root confinement, and only the weight of stems formed the previous season was not reduced by fruiting. Fruit dry weight was 30.0 g/tree for large- and small-container treatments, causing the yield efficiency (g fruit/g total dry wt) to be 50% higher for confined trees. Fruit red color, weight, and diameter were unaffected by root confinement, but higher flesh firmness and a more green ground color of the fruit surface from root-confined trees suggested that confinement delayed maturity. Vegetative growth was not reduced by lack of nonstructural carbohydrates in confined trees. A was reduced by root confinement on only the first of 11 measurement dates, whereas fruiting increased A on 5 of 8 measurement dates before fruit harvest. Fruit removal reduced A by 23% and 31% for nonconfined and confined trees, respectively, within 48 h of harvest. Leaf starch, sucrose, sorbitol, and total carbohydrate levels were negatively correlated with A when data were pooled, but inconsistent responses of A to carbohydrate content indicated that factors other than feedback inhibition were also responsible for the reduction in A on nonfruited trees. We hypothesized that a physiological signal originating in roots of confined trees reduced vegetativegrowth without reducing fruit growth.

Reappraisal of seasonal apple fruit growth

1993 ◽  
Vol 73 (2) ◽  
pp. 549-556 ◽  
Author(s):  
I. Schechter ◽  
J. T. A. Proctor ◽  
D. C. Elfving
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Dry Matter ◽  
Dry Weight ◽  
Apple Fruit ◽  
Fruit Growth ◽  
Full Bloom ◽  
Relative Growth ◽  
Dry Matter Concentration ◽  
Matter Concentration

Three apple cultivars (McIntosh, Delicious and Empire) were used in 1989 to study seasonal fruit growth. Fruit fresh weight (FW), dry weight (DW), dry matter concentration (DMC) and relative growth rate (RGR) were regressed against days after full bloom (DAFB) while partitioning the fruit growth curve into either two or three linear phases. Linear phases in fruit DW and FW development were evident throughout most of the growing season. However, cultivars differed in seasonal FW and DW accumulation totals and daily rates. Fruit RGR gradually declined until 75–80 DAFB, when it reached a low and constant rate until harvest. The DMC of fruitlets at about 30–35 DAFB was about half that at full bloom. After an additional 20–30 d during which DMC increased, fruits maintained a relatively stable DMC level to the end of the season. Key words: Malus domestica Borkh., fresh and dry weight, dry matter concentration, relative growth rate

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 CROP LOAD AND LIMB GIRDLING AFFECT APPLE FRUIT SIZE, COLOR, AND QUALITY

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 625d-625
Author(s):  
John A. Barden
Keyword(s):  
Linear Regression ◽  
Fruit Size ◽  
Apple Fruit ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Sectional Area ◽  
Cross Sectional ◽  
Crop Load ◽  
Golden Delicious ◽  
Old Trees

In 1990, 15-yr-old `Smoothee Golden Delicious' trees on M.9, M.9/MM.111, and MM.111 were used. On each of 4 trees per rootstock, 3 branches (1.0-1.7 cm dia) were selected. On 7 June (45 DAFB), crop loads were adjusted to 3, 5, or 7 fruit per cm2 branch cross sectional area (BXSA), and each branch was girdled. On 6 Sept all fruit were harvested; fruit weight, ground color, percent blush, soluble solids, starch, and firmness were regressed against crop load. Each was negatively related to crop load, most strongly for soluble solids, ground color and blush. Rootstock influenced several factors and some interaction with crop load occurred. In 1991, heavily cropping 10-yr-old trees of Empire/M.7A were used. One each of 7 trees, branches (1.2-2.0 cm dia) were thinned to 4, 8, or 12 fruit/cm2 BXSA on 5 June (40 DAFB). One branch per crop load per tree was girdled on 5 June. On 29 Sept fruit were harvested for evaluation. ANOVA indicated significant interactions between crop load and girdling for fruit weight, firmness, soluble solids and starch. Each showed a significant negative linear regression with crop load on girdled branches; on ungirdled branches none of the regressions were significant.

scholarly journals Vegetative and Reproductive Response to Fruit Load in Two Jojoba (Simmondsia chinensis) Cultivars

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 889
Author(s):  
Aviad Perry ◽  
Noemi Tel-Zur ◽  
Arnon Dag
Keyword(s):  
Vegetative Growth ◽  
Accumulation Rate ◽  
Dry Weight ◽  
High Yield ◽  
Lower Amount ◽  
Simmondsia Chinensis ◽  
Alternate Bearing ◽  
Fruit Removal ◽  
Growing Period ◽  
Fruit Load

Jojoba (Simmondsia chinensis) is a wax crop cultivated mainly in arid and semi-arid regions. This crop has been described as an alternate-bearing plant, meaning that it has a high-yield year (“on-year”) followed by a low-yield year (“off-year”). We investigated the effect of fruit load on jojoba’s vegetative and reproductive development. For two consecutive years, we experimented with two high-yielding cultivars—Benzioni and Hazerim—which had opposite fruit loads, i.e., one was under an on-year load, while the other was under an off-year load simultaneously. We found that removing the developing fruit from the shoot during an off-year promotes further vegetative growth in the same year, whereas in an on-year, this action has no effect. Moreover, after fruit removal in an on-year, there was a delay in vegetative growth renewal in the consecutive year, suggesting that the beginning of the growing period is dependent on the previous year’s yield load. We found that seed development in the 2018 season started a month earlier than in the 2017 season in both cultivars, regardless of fruit load. This early development was associated with higher wax content in the seeds. Hence, the wax accumulation rate, as a percentage of dry weight, was affected by year and not by fruit load. However, on-year seeds stopped growing earlier than off-year seeds, resulting in smaller seeds and an overall lower amount of wax per seed.

scholarly journals Leaf Photosynthesis and Carbon Metabolism Adapt to Crop Load in ‘Gala’ Apple Trees

Horticulturae ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 47
Author(s):  
Xiaohua Yang ◽  
Li-Song Chen ◽  
Lailiang Cheng
Keyword(s):  
Higher Plants ◽  
Herbaceous Plants ◽  
Carbon Export ◽  
Apple Trees ◽  
Cross Sectional ◽  
Crop Load ◽  
Woody Perennials ◽  
Source Sink ◽  
C Assimilation ◽  
Reduced Activity

It is widely accepted that a tight coordination between carbon (C) utilization in the sink and C assimilation and metabolism in the source exists in higher plants. However, much of our current understanding is based on research from herbaceous plants, where the source and sink interaction is less sophisticated compared to woody perennials with a significant sink presence. Apple (Malus x domestica Borkh.) is a good representative of the latter category, and its production and transport of sorbitol, in addition to sucrose, adds complexity to C regulation. In this study, four-year-old “Gala”/”M.26” apple trees were subjected to crop load levels at 2.5, 7.5, and 15 fruits/cm2 trunk cross-sectional area. Low crop load trees exhibited reduced leaf C assimilation and extra accumulation of non-structural carbohydrates (NSC). This was primarily a result of reduced activity of Rubisco and increased activities of key enzymes that synthesize starch, sucrose, and sorbitol. Among the NSC, leaf starch was found to be most sensitive to crop load and could function as a leading indicator for source–sink balance in apple. However, even the high crop load trees still retained a significant amount of NSC in leaves at dawn, demonstrating that apple is fundamentally different from herbaceous plants in the way it balances leaf carbon inventories at dawn with carbon export at night for sink growth.

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