fruit drop
DESCRIPTION
causes and controlTRANSCRIPT
TAMIL NADU AGRICULTURAL UNIVERSITY Coimbatore-641003
VISHNU KUMAR MISHRA ID NO 13-533-011 1st M.Sc.(Hort)
Growth and development of horticultural crops HOR501(2+1) Assigned topic- Causes and remedies of fruit drop
Causes and remedies of fruit drop
Fruit drop Fruit drop is the detachment or separation of a fruit
from a branch of a tree or a plant, caused by the formation of a separation of layer of cells on the fruit stalk due to a series of physiological and biochemical events.
The substances bonding the cells of the separation layer dissolves and the cells separate from each other. Middle lamella became soft by the action of hydrolysing enzymes (pectin esterase)(Szalai, 1994).
At this stage of the process, the fruit is attached to the plant only by a vascular bundle.
A serious problem in mango (alphonso), citrus, avocado, peach, figs etc and also observed in apple and pear.
Causes of fruit drop
Internal factors
External factors1. Conditions of
pollination and fertilization
2. Seed content of fruits
3. Competition between the organs of plants
Competition between the vegetative and generative organs
Competition between the generative organs
4. Physiological and hormonal bases
1. Climatic conditions
& Meteorological
conditions
2. Phytotechnical
interventions
Irrigation, water supply
Nutrition
Harvest
3. Biotic factorsDiseases
Pests
Internal factors
Conditions of pollination and fertilization
Ortega et al. (2004)- More fruit drop- if the pollination occur - 4th or 6th day after the emasculation of flower buds Ex- Aonla
In Sweet cherries, more fruit drop due to embryo abortion or competition between the seed and the pericarp for resources (Bargioni, 1978).
In the variety ’Napoleon’ of cherry, preharvest fruit drop is observed caused by the degeneration of the endosperm (Guerro-Pietro, 1984).
According to Tylus (1975), preharvest fruit drop is observed only in varieties characterized by high rates of fruit set.
Excess fruit drop due to insufficient resources(Wellington et al ,1975).
Seed content of fruits
The most important precondition of the fruit to be maintained on the tree is its seed content.
The seed content of fruits – as Auxin factories – are important factors of maintaining fruits on the tree.
Fruits with less seeds are more susceptible to environmental adversities, i.e. water stress, poor nutrition, etc. and are prone to drop fruits (Webber,1923; Stosser, 2002).
Teskey & Shoemaker (1972) claimed that in apple, fruits containing less than 3 seeds are shed first when fruit set was abundant.
Murneek (1987) too estimated the fruit drop of pears containing less than 3 seeds per fruit.
Competition between the vegetative and generative organs
The number of fruits on the tree- depends on organic nutrients furnished by the leaves nearby, whereas the rest is prone to be dropped (Papp, 2001).
Brunner (1982), refers that the balance expressed by the ratio of leaves and fruits.
In apple, 1–4 leaves for one fruit set, 10–15 leaves around June drop and 40 leaves at the end of fruit development needed.
The weak development of the leaf area, induces fruit drop.
Young leaves delay the abscission of ripe fruits, whereas mature leaves promote the abscission of fruits by stimulating the transport of ABA (Dávid, 1980).
Competition between the generative organs
The flower or fruit set, started growing earlier becomes dominant than flower or fruits lagging relatively behind (Bubán, 2002). This type of dominance is called primogenous (Bangerth, 1990).
The fruits which developed at distal end and lateral branches, are more prone to fruit drop.
Physiological and hormonal bases
The abscission of young fruits depend on auxin as a correlative dominance signal (Bangerth, 1990).
The endosperm of the ovule (seed primordial) is the source of auxin production.
Unfertilized flowers lack in seeds so no growth substances therefore they abscise soon (Friedrich, 2000).
According to Bubán (2003), the premature abscission of fruits is determined by the relative concentrations of IAA and ABA.
The role of ABA in abscission has been proved in apple (Vernieri et al., 1992), litchi (Yuan & Huang, 1988), citrus (Talon et al., 1990b; Sagee & Erner, 1991; Goren, 1993; Gomez-Cadenas et al., 2000) as well as in cotton (Guinn & Brummett, 1988).
Tari (2004b) proves the presence of jasmonic acid in abscission.
According to Tari (2004), maintains that the principal regulator of abscission is ethylene, which is suppressed essentially by IAA.
External factors
Climatic conditions Premature fruit drop is caused by high probability
adverse environmental conditions (Soltész, 1997).
Eggert (1960) referred the temperature(more than 28°c) as an important factor responsible for the June drop of apple.
Surányi & Molnár (1981) refer also to the effect of temperature in the fruit drop of apricot.
Coit & Hodgson (1919), concluded that high temperature and low relative humidity caused in ’Navel’ orange a high degree of June drop.
Haas (1926) recognized the water loss is an immediate cause of June drop.
Tomato fruit drop - <55° F temperature
High temperature (39-42°C) during stage of fruit set development causes fruit drop. Ex- cashew nut
Preharvest fruit drop is aggravated by wind and weather adversity (Nagy & Kovács, 2005). The pear variety ‘Hardy’ is especially susceptible to wind (Göndörné, 2000).
Fruit drop of sweet cherry is more when cool and rainy weather is followed suddenly by a dry and hot period.
Poor light conditions (e.g. shading) increase the incidence of fruit drop in sweet cherry (Patten & Proebsting, 1986)
Phytotechnical interventions Fruit thinning--- Soltész, (1997) refers that right timing of
fruit thinning in apple is important to reduce fruit drop. Ex- grapes
Irrigation, water supply--- restricted amounts of water is one of the causes of fruit drop.
Heavy fruit drop may be caused also by excessive watering, which made split fruits near maturity (Anonymus, 2005).
Nutrition-- An overload of fruits is often considered to induce drop of young fruit because of the relative scarcity of nutrients (Tari, 2004c).
Tarita et al. (1979) stated the same in relation of sour cherry, which could be saved from the first fruit drop by nitrogen.
According to Feucht (1970), on the other hand, excessive nitrogen, more than 21% content in the leaves, causes a heavy drop of fruits in blueberry.
Potassium, boron and calcium also play a major role in fruit drop.
Harvest:-- In the regulation of fruit drop, the timing of harvest fulfils an important role.
The technology of harvest is an important moment too especially in mechanical harvest.
Biotic factors
Diseases Symptoms of senescence also in healthy tissues, which are often
leading to fruit drop.
Premature fruit drop caused by scab (Venturia carpophyla) and drought condition in apricot and peach is particularly dangerous.
Fruit drop of walnuts may be induced by Gnomonia sp.
Gooseberry, blueberry and blackberry are haunted by grey mould (Botrytis) causing fruit drop.
In peach, Taphrina is registered as most important, in all stone fruits the scab and in small fruits the grey mould is threatening.
The fungus causing fruit rot (Monilinia fructicola) is generally recognized as initiating fruit drop. Ex- Apple
The leaf-curl disease of peach (Taphrina deformans) fruit drop may occur at vigorous infection.
Fruit rot (Phytopthora sp.)- fruit drop in nutmeg.
Pests Animal pests belong to the most frequently met agents causing fruit drop (Singh et al., 2005).Pollu beetle causes the berry drop in black pepper.
The grub of the red backed proboscide weevil penetrate into the fruit and feed on the seeds
affected fruits stop growing, shrivel and dropped
EX- Apple, Pear, Quince, Plum, Almond
Proboscid weevil of the hazel (Balaninus nucum) and of the oak (Balaninus glandium)
brings up their grub within the hard shell of the nut
They drill a hole of cc. 2 mm diameter and feed on the kernel
weevil is the precursor of the fungus (Monilia fructigena)
fruit drop(70%)
The oriental fruit moth (Grapholitha molesta) is mainly found on peach, apricot causing fruit drop.
The apple moth (Cydia pomonella) is responsible for fruit drop (30–40%). Ex- Apple, pear, quince and walnut (Garai, 2005).
In May and early June, the Plum moth (Grapholitha funebrana)
attacks the green fruits of minor size
small holes and gum extrusions appear
. fruits drop(65%) Apple wasp (Hoplocampa testudinea)
larvae drill a hole into the fruitlet
reddish brown or black juice appears entrance of hole
white larvae are identified within themFruit drop (72.6%)
Codling Moth(apple moth)
Remedies of fruits drop
Pollination PGR Mineral nutrient(INM) IPM IDM
Pollination
The crossing between pant shivani and
pant sujata gave reduced fruit drop (59.86%).
Hand pollination of nonpareil almond with pollen from angle, resulted in reduced fruit drop.
In musket and ruby red, the fruit drop was lowest under natural self pollination.
In Bangalore purple and Thompson seedless, self hand pollinated results in lowest fruit drop.
kagzi × Bhadri recorded maximum fruit set and reduced fruits drop followed by kagzi kalan × pummelo
Plant growth regulators Fruit drop occurs when auxin level goes down, hence we can
check the fruit drop by the application of auxin exogenously.
NAA (20 ppm) most effective in reducing fruits drop in 16- year old Ber cv. Umran.
Spray of GA3 (60 ppm) recorded the lowest fruit drop (75%) and highest fruit set (16.6%) in Ber cv. Umran.
Application of 2,4-D (10 ppm) and (20 ppm) resulted in minimum percentage of fruit drop in Kinnow mandarin and Nagpur mandarin respectively.
20 ppm of NAA- mango – min fruit drop
Fruitone (NAA), Re Tain, AVG(aminoethoxyvinylglycine) & Harvista act as ethylene inhibitor.
Mineral nutrients(INM)
Foliar application of borax(0.1%)- in June July- reduced fruit drop – Bael cv kagzi
Spraying with 1.5% potassium sulfate and 1.5% potassium nitrate - lowest fruits drop(75.22%) - Ber cv Umran.
Boron 0.4% + 10 ppm of 2,4-D application- reduced fruit drop- in litchi
Application of 0.75% zinc sulfate – less drop – in sweet orange cv Jaffa
IDM and IPM
Cultural operation
Mechanical operation
Biological operation
Chemical operation
IDM and IPM Prune the plants after harvesting to minimize pest and
disease incidence.
Dropped fruits should not be left in the field as they acts as carrier for the disease.
Bait containing Malathion or Fenthion 0.05%+1% crude suger should be hanged two months before fruit ripening.
carbaryl@2g/l of water should be sprayed twice at 12 days interval after fruit set.
Avoid unfavorable environmental conditions.
Predatory Beetles
Predatory Bugs
lacewings
Case studies
Moderate plant water stress reduces fruit drop of “Rojo Brillante” persimmon (Diospyros kaki) in a
Mediterranean climate
Objective to establish and quantify the effects of plant water stress
on fruit drop of the ‘Rojo Brillante’ persimmon cultivar.
Methods A field experiment was conducted during three
consecutive seasons with mature trees. Three irrigation regimes were tested: Control, always well watered; and two deficit irrigation (DI) treatments.
(1) Control, where irrigation was applied in order to minimize soil water deficit.
(2) DIearly, where deficit irrigation (50% of Control irrigation regime) mid May to mid July.
(3) DIlate where 50% of the Control regime was applied from mid July to the end of August
E. Badal, T.A. Abd El-Mageed, I. Buesa, D. Guerra, L. Bonet, D.S. IntriglioloMoncada, Valencia, Spain
Result Moderate plant water stress (stem >−1.3 MPa)
occurring early in the summer (mid-May to end of June, coinciding with the fruit drop waves) decreases fruit drop.
Early season water stress had a greater effect on reducing fruit abscission during the second wave of fruit drop.
In semi-arid climates, this knowledge can be used for increasing ‘Rojo Brillante’ persimmon fruit set by restricting irrigation applications during late spring.
Water stress applied later, at the end of the fruit drop period, had less of an effect on reducing fruit drop.
Response of chilli (Capsicum annum L.) to plant growth regulators.
Aim Flower and fruit drops in chilli are the major problems.
A field experiment was conducted to identify most effective plant growth regulator in improving fruit set and reduce fruit drop.
Methods The experiment was carried out in a split plot design,
keeping varieties (Jwala and Suryamukhi) in main plots, and growth regulators (2,4-D 2 ppm, NAA 40 ppm, triacontanol 5 ppm and GA3 10 ppm, and control) in sub-plots at Rampur, Chitwan, Nepal during winter-summer of 2003/04.
The treatments were replicated four times.
Chaudhary, B. R. 2004. [Student I. D. No. R-2002-HRT-06-M, Advisor: M. D. Sharma, Members: S. M. Shakya and D. M. Gautam].
The application of 2,4-D and triacontanol increased number of short and medium styled flowers thereby improving fruit set.
Yield components were superior in cv. Suryamukhi due to 2,4-D, and triacontanol than Jwala.
Suryamukhi gave more fresh (11%), and oven dry (8%) fruit yields over Jwala.
2,4-D and triacontanol increased fruit yields by reducing fruit drop.
The application of growth regulators was found
ineffective to control flower and fruit drop in winter season.
Result
Studies on training systems and NAA application on bell pepper production in polyhouse
Aim Capsicum (Capsicum annuum L.) is an important
off-season vegetable crops grown in the mid-hills of Himachal Pradesh.
Production and productivity of this crop is low because of high flower and fruit drop.
The present investigation was carried out to find out the best training system and an appropriate concentration of naphthalene acetic acid (NAA)
Y.R. Shukla, Deepa Sharma' and Upasna Tegta Department of Vegetable Science,Dr. Y.S. Parmar University of Horticulture and ForestryNauni, Solan
Methods
Three concentrations of Naphthalene Acetic Acid (N1- 5 ppm spray, N2 - 10 ppm spray and N3 - 15 ppm spray) with Control (no NAA application) were applied.
Three systems of training, viz. To (No Training), T1 (Two stem Training) and T2 (Four stem training) were followed.
Result Two sprays of NAA @ 15 ppm proved best for plant
height, total number of flowers per plant, per cent flower drop, per cent fruit set, days to first picking, number of fruits per plant, fruit weight and total yield per plant.
Effect of training systems and NAA on various horticultural traits of bell
pepperTreatments % fruit drops
T 0 62.8
T1 57.4
T2 59.4
N0 70.4
N1 63.2
N2 56.1
N3 48.3
References
Pandy, S.N., Sinha, B.K. 2007: Plant Physiology, Fourth Edition
Jain, V.K. 2009: Fundamentals of plant physiology, S. Chand & company Ltd.
International Journal of Horticultural Science 2007, 13 (3): 13–23,Agroinform Publishing House, Budapest, Printed in Hungary, ISSN 1585-0404
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