scholarly journals EFFECTS OF PREHARVEST IRRIGATION CUTOFF DURATION ON FRENCH PRUNE TREE PERFORMANCE

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1172a-1172
Author(s):  
G. S. Sibbett ◽  
D. Goldhamer ◽  
S. Southwick ◽  
R.C. Phene ◽  
J. Yeager ◽  
...  

Variable lengths of water deprivation immediately prior to harvest were imposed on mature French prune trees for four consecutive years. Irrigation cutoff durations were about 45, 37, 30, 22, 17 and 12 days prior to harvest during 1986-89.Predawn leaf water potential best reflected water deprivation length and reached minimum values of about -1.5 MPa with the most severe cutoff. Magnitude of peak stomatal conductance was reduced and occurred earlier in the day with longer cutoff regimes.Rate and time-course development of preharvest fruit drop was variable from year-to-year, but there were no significant differences in total drop between cutoff treatments. Only in the fourth year, following three years of no difference were tree fruit load and yield significantly reduced but then only with the most severe cutoff. Soluble solids were higher and drying ratios lower with the longer cutoffs. Fruit size was significantly reduced in the third year of the experiment. Trunk circumferences were significantly lower only with trees subjected to the longer cutoff regimes.

Agronomy ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1305
Author(s):  
Marco Caruso ◽  
Alberto Continella ◽  
Giulia Modica ◽  
Claudia Pannitteri ◽  
Riccardo Russo ◽  
...  

Citrus fruit quality and scion productivity are influenced by the choice of rootstock. We aimed to evaluate the effect of rootstocks on yield and fruit quality of Mandared, a triploid pigmented mandarin. To do so, we established a rootstock field trial on a high pH soil (8.6) in which Mandared was grafted onto 11 rootstocks. These included some standard rootstocks, such as trifoliate orange ((Poncirus trifoliata (L.) Raf.), Troyer citrange (Citrus sinensis (L.) Osb. × P. trifoliata), Swingle citrumelo (Citrus paradisi Macf. × P. trifoliata), and C35 citrange (C. sinensis × P. trifoliata), as well as new releases from the Council for Agricultural Research and Economics (CREA, Acireale, Italy) and the University of California Riverside (UCR). The cumulative yield was measured over five consecutive years, while fruit quality was analyzed for two years. The trees on C35, C57 (Citrus sunki Hort. ex. Tan. × P. trifoliata), and C22 (C. sunki × P. trifoliata), started to set fruits one year earlier than the others. The trees on C57 provided some of the highest cumulative yields and canopy volumes. The production of Mandared grafted onto C57 was double that of Mandared grafted onto Troyer, while Mandared grafted onto C35 and C22 resulted in the best yield efficiency. The trees on Swingle and C57 significantly reduced the pre-harvest fruit drop, to which Mandared is particularly sensitive. However, grafting Mandared onto Swingle resulted in the highest variation among replicates, probably due to its high sensitivity to iron chlorosis. Most of the fruit quality parameters, such as fruit size, total soluble solids (TSS), and acidity were not significantly different among the rootstock treatments. However, fruits produced by Mandared grafted onto C22 had one of the highest rates of anthocyanin accumulation. The results indicate that C57, C35, and C22 were the most suitable rootstocks for Mandared in South-Eastern Sicily.


2008 ◽  
Vol 18 (4) ◽  
pp. 678-684 ◽  
Author(s):  
G. Schnabel ◽  
C.H. Crisosto

Quinone outside inhibitor (QoI) fungicides can improve the yield and quality of cereal crops in the absence of disease pressure through the so called “greening effect,” but little is known about the potential beneficial effects on deciduous tree fruit crops. In a multiyear and multicultivar study carried out in South Carolina (2005 and 2006) and California (2006), we examined the potential influence of the QoI fungicide pyraclostrobin on antioxidant activity and commercially important peach (Prunus persica) fruit quality attributes, including fruit size, coloration, firmness, soluble solids concentration, and yield. Experimental orchards were sprayed according to commercial guidelines to manage insect pests and diseases. A pyraclostrobin + boscalid mixture was applied up to five times per season starting 1 week after the physiological stage of “shuck off” until 1 to 2 weeks before harvest. Fruit size was measured weekly between “shuck off” and harvest, whereas the other fruit quality attributes were determined at harvest. Results indicate no consistent impact of the pyraclostrobin + boscalid mixture on same-year fruit size development or other fruit quality attributes in orchards with no or very little disease pressure. To our knowledge, this is the first in-depth evaluation of the potential effects of a QoI fungicide on commercially important tree fruit quality attributes.


2017 ◽  
Vol 39 (3) ◽  
Author(s):  
GENTIL CARNEIRO GABARDO ◽  
JOSÉ LUIZ PETRI ◽  
FERNANDO JOSÉ HAWERROTH ◽  
MARCELO COUTO ◽  
LUIZ CARLOS ARGENTA ◽  
...  

ABSTRACT The aim of this study was to evaluate the efficacy of metamitron or metamitron plus benzyladenine as a post-bloom thinner on ‘Baronesa’ and ‘Fuji’ apples. Three experiments (rate, timing and BA combination) were conducted during two crop seasons, 2013/14 and 2014/15 at the experimental station located in Caçador, SC. Fruit set, fruit drop, yield per tree, fruit size and flowering return were assessed. The efficacy of metamitron was affected by time of application, and when applied at petal fall, promoted the proper adjustment of the production load of plants. Yield per plant reduces, whereas the allocation of fruits in categories of greater size increases proportionally to the increase in the metamitron concentration applied. However, there is excessive fruit drop with the use of high concentrations. The addition of BA to metamitron also promoted fruit drop; however, no difference was observed between single application of metamitron and BA addition. Metamitron shows great potential to be used as thinner for apples, since it reduces the number of fruits per tree.


Author(s):  
A. Pérez-López ◽  
A. Sotomayor-Ríos ◽  
S. Torres-Rivera

A search for good chironja clones was performed on several chironja seedlings grown on a Typic Tropohumults soil at the Corozal Agricultural Substation . This research demonstrated that chironja seedlings can be selected for yield per tree, fruit size, number of seeds per fruit, peel weight, citric acid, pH, soluble solids to acid ratio, and quality index. However, the high coefficient of variability for number of seeds, cumulative weight and number of fruits per tree during eight bearings and the quality index indicates that the probability of selecting for these characters is higher than that for fruit size, citric acid, pH, and soluble solids/acid ratio. The study also showed a great variability of the seedlings, following the frequency distribution typical of populations, indicating that in order to maintain uniform populations the chironja must be propagated through vegetative plant tissues, like grafting, instead of by seeds.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 590c-590
Author(s):  
Kevin R. Day ◽  
Ted M. DeJong

Girdling has been shown to increase fruit size and soluble solids concentration and advance fruit maturity. Performed improperly, girdling can also have a debilitating effect on trees. To minimize this, growers often use alternatives to the standard complete girdle. However, the efficacy of these alternative techniques has not been evaluated. Three methods of girdling: 1) complete girdle of all scaffolds, 2) complete girdle of all but one “nurse” scaffold, and 3) spiral (overlapping) girdle of all scaffolds, were compared to ungirdled trees to determine their effect on fruit and tree performance. All of the girdling treatments increased fruit size and marketable yield, and advanced maturity over ungirdled trees. Fruit on ungirdled nurse limbs were similar in size to fruit on ungirdled trees, while the fruit on the remaining girdled limbs were slightly larger than fruit on the trees which had all scaffolds girdled. Overall fruit size and yield of trees with a nurse limb were similar to the other girdle treatments.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 548a-548 ◽  
Author(s):  
D.M. Glenn ◽  
G. Puterka ◽  
T. Baugher ◽  
T. Unruh ◽  
S. Drake

Hydrophobic particle film technology (HPF) is a developing pest control system for tree fruit production systems. Studies were established in Chile, and Washington, Pennsylvania, and West Virginia in the United States, to evaluate the effect of HPF technology on tree fruit yield and quality. Studies in Chile, Washington, and West Virginia demonstrated increased photosynthetic rate at the leaf level. Yield was increased in peaches (Chile) and apples (West Virginia), and fruit size was increased in apples (Washington and Pennsylvania). Increased red color in apple was demonstrated at all sites with reduced russetting and `Stayman' cracking in Pennsylvania. HPF technology appears to be an effective tool in reducing water and heat stress in tree fruit resulting in increased fruit quality.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 513c-513 ◽  
Author(s):  
Martin J. Bukovac ◽  
Jerome Hull ◽  
John C. Neilsen ◽  
Michael Schroeder ◽  
Georg Noga

NAA is used extensively for fruit thinning of apples to increase fruit size and to promote return bloom. In some cultivars, even if thinning is achieved, fruit size at harvest may be less than expected based on crop load. CPPU, N-(2-chloro-4-pyridinyl)-N.-phenylurea, has been shown to increase fruit growth in apples, grapes, and kiwi. We evaluated combinations of NAA and CPPU on thinning, fruit growth and return bloom in Redchief `Delicious', `Elstar', and `Gloster'. CPPU was applied at 5 mgμL–1 (based on 0 to 10 mgμL–1 response curve) in combination with 15 mgμL–1 NAA as high-volume sprays at 7 to 10 mm KFD. Yield and fruit size distribution (on total yield) were used as index of response. In `Delicious', CPPU (3-year study) increased % large (70 mm+) fruit, but in the presence of NAA % large fruit was reduced 2 of the 3 years. CPPU did not induce significant thinning. There were no significant effects on color or soluble solids; firmness was increased slightly and seed number reduced. The L/D ratio was increased and uneven lobe and carpel development was common. CPPU had no significant effect on return bloom in presence or absence of NAA, but NAA increased bloom in both the presence and absence of CPPU. With `Elstar' (2-year study) there was no significant thinning with either chemical, but CPPU increased mean fruit size and % large (70–80 mm) fruit over nonthinned, but not significantly greater than NAA alone. There were no significant differences in firmness, color, soluble solids or seed number. NAA + CPPU did not inhibit fruit growth or cause excessive uneven carpel development. Frost damage reduced crop load in `Gloster' where results were similar to `Elstar' except seed number was reduced by the NAA + CPPU combination.


Horticulturae ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 34
Author(s):  
Christopher Menzel

Five strawberry (Fragaria × ananassa Duch.) cultivars were grown in Queensland, Australia to determine whether higher temperatures affect production. Transplants were planted on 29 April and data collected on growth, marketable yield, fruit weight and the incidence of small fruit less than 12 g until 28 October. Additional data were collected on fruit soluble solids content (SSC) and titratable acidity (TA) from 16 September to 28 October. Minimum temperatures were 2 °C to 4 °C higher than the long-term averages from 1965 to 1990. Changes in marketable yield followed a dose-logistic pattern (p < 0.001, R2s = 0.99). There was a strong negative relationship between fruit weight (marketable) and the average daily mean temperature in the four or seven weeks before harvest from 29 July to 28 October (p < 0.001, R2s = 0.90). There were no significant relationships between SSC and TA, and temperatures in the eight days before harvest from 16 September to 28 October (p > 0.05). The plants continued to produce a marketable crop towards the end of the season, but the fruit were small and more expensive to harvest. Higher temperatures in the future are likely to affect the economics of strawberry production in subtropical locations.


1983 ◽  
Vol 23 (120) ◽  
pp. 106 ◽  
Author(s):  
WB McGlasson ◽  
JB Sumeghy ◽  
LL Morris ◽  
RL McBride ◽  
DJ Best ◽  
...  

F1 hybrids of the nor non-ripening mutant tomato in different genotypic backgrounds were evaluated between 1978-81. The nor gene in the heterozygous condition delayed the start of ripening by a few days, increased the interval between breaker and the table ripe stage to 10 d at 21�C compared with 6 d for fixed cultivars and increased the storage life of ripe fruit at 21�C by about 50%. The retention of firmness by ripe fruit of the hybrids was affected by parental genotype. Fruit of some hybrids was firmer or as firm as fruit of the hard commercial Flora-Dade but others were much softer. A major problem with fruit of F1 nor hybrids was poor colour development. The fruit ripened to an orange-red colour, and strains with green shoulders developed an unattractive yellow on the shoulders. This deficiency was most pronounced in fruit picked before the appearance of red colour. The best hybrid found in this study was 75T10-1 x nor backcross 4 or 5 Heinz 1350. Fruit size, soluble solids, pH, titratable acidity, total ascorbic acid levels and acceptability except external colour of table ripe fruit appeared to be influenced by the parental genotype rather than by the nor gene. Since there were marked differences between hybrids with different genotypic backgrounds, it should be possible to breed nor hybrids with improved colour and firmness.


1993 ◽  
Vol 73 (3) ◽  
pp. 847-855 ◽  
Author(s):  
H. A. Quamme ◽  
R. T. Brownlee

Early performance (6–8 yr) of Macspur McIntosh, Golden Delicious, and Spartan apple (Malus domestica Borkh.); Fairhaven peach [Prunus persica (L.) Batsch.]; Montmorency sour cherry (P. cerasus L.); and Lambert sweet cherry (P. avium L.) trees, tissue cultured (TC) on their own roots, was compared with that of the same cultivars budded on commercially used rootstocks. TC trees of all apple cultivars were similar in size to trees budded on Antonovka seedling or M.4 and exceeded the size of trees budded on M.26. They were delayed in flowering and in cropping compared with trees budded on M.26 and M.4. No difference in titratable acidity, soluble solids, flesh firmness, weight, flavor, and color between fruit from TC trees and from trees on M.4 and Antonovka seedlings was detected in 1 yr of measurement. However, fruit from TC Golden Delicious was more russeted and fruit from TC Spartan had more soluble solids. The difference in fruit appearance between TC and budded trees may result from a root-stock effect or a difference in budwood source, because Spartan fruit from trees on M.4 was more russeted than Spartan fruit from TC trees, but was not different from Spartan fruit from trees on Antonovka seedling. Trees of Macspur McIntosh on TC M.26 and on stool-layered M.26 were similar in size and yield efficiency. TC Fairhaven was larger in size than Fairhaven on Siberian C seedling, but was less yield efficient. No difference in fruit size, flesh firmness, or color was detected between fruit harvested from peach trees on the different roots. Montmorency and Lambert TC and on F12/1 were similar in tree size, respectively, but Montmorency and Lambert TC were more yield efficient than on F12/1. Fruit of TC Lambert was lighter in color and had higher titratable acidity than that of Lambert on F12/1, perhaps a result of earlier fruit maturity. Key words: Apple, peach, sweet cherry, sour cherry, self-rooted, rootstocks


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