UNFRUITFULNESS AND

ASSOCIATED FACTORS

Presentation by:Junaid Abbas (12-Arid-374)Zeeshan Khan (12-arid-437)

Unfruitfulness Important determinant in yield potential of

orchards.

Causes are broadly classified as:-

1. external factors

2. Internal factors

External factors Besides change of phases in life cycle on flowering of any

fruiting plant, others factors that effect fruitfulness are:-

Environment Water relations Nutrient Supply Rootstock Pruning Age & vigor of plant Locality Insect , pests and diseases Miscellaneous

Environmental Factors Temperature Rainfall Wind Frost Hailstorm Cloudy weather Light intensity

Water relations Moisture excess or deficit should be

avoided during critical stages .

Undesirable fruit drop can be observed in orchards, as a result.

Remedies such as irrigation, tillage, cover crops and wind-breaks can help.

Nutrient Supply Very important factor for optimum

production and avoiding unfruitfulness.

Balanced supply of manures and fertilizers can maximize the benefit.

Excessive N. fertilizers can cause poor fruit set due to carbohydrate shortage.

Rootstocks Important material in inducing desirable

benefits onto scion cultivar.

Trees that bear fruit late can be made to bear it early by better variety's rootstock.

Examples include apple, pear, mango, etc.

Pruning Important in maintaining the rhythm of

fruiting in deciduous fruit plants

Heavy pruning is needed in raspberry, pear & apple trees for better fruit-set

whereas grapes require lighter pruning for more yield by increasing cluster size.

Age and vigor Young and vigorous trees of plum and

apples show more unfruitfulness then mature and less vigorous ones.

Age of fruit tree is more significant factor then its vigor while determining degree of fruitfulness.

Locality Various factors such as soil, temperature,

humidity, light etc. constitute locality influence on fruit-set.

Results in changed behavior of same fruit tree at different places, e.g. commercial mango varieties of south Indian region don’t perform better under north Indian conditions.

Insect-pests & diseases Mango hopper destroys ALL flowers in a mango

or the whole orchard, after infestation on its blossoms. Other serious insect pests include moth, leaf roller, aphids, thrips and mealy bug.

Fire blight, Scab, and powdery/downy mildew are serious diseases of fruits, which can be managed through spraying and other measures to decrease unfruitfulness in fruit trees and orchards.

Miscellaneous factors Mismanagement of orchards.

High concentrations of highly salt.

Continuous spray of chemicals.

Dio-ecious Plants Unisexual Bears only one type of Flower either

pistillate or staminate on one plant. Following are some examples

Date Palm: Dioecious Plant Proper Pollination is required For natural combination, male and

female trees should be in equal number. For artificial pollination , 1 male: 30

females is sufficient In General, 4 to 5 male for 100 female

trees are sufficient for commercial crop

Selection of Male Plant Following Points should be taken into consideration Male plant, which produce thick and bushy

inflorescence with large number of male strands, should be preferred

Male strand should have abundance of pollen. It can be judged by visual observations. Those strand, which releases abundance of yellowish dust on shaking are better than the others

The male flowers that emerge early in the season should be marked and used to avail their pollen for pollinating early female trees.

Strawberry Widely grown dieocious fruit plant Most varieties bear perfect flowers Some of the best varieties bear pistillate

flowers only No proper attention was given to secure

better pollination of pistillate flowers Observation of Nicholas Hong worth He taught that such varieties should be inter-

planted with perfect flowering varieties for a better yield

Papaya1. Pure pistillate flowering plants (self fruitful)2. Pure staminate flowering plants (un fruitful and

common)3. Plant producing both staminate and perfect flowers4. But with sterile pollen, more often called pseudo-

hermaphrodite plants (self fruitful)5. But neither pollen nor pistils are fertile; more often

called sterile hermaphrodite plants(un fruitful)6. Plant producing staminate, pistillate and perfect flowers7. Pistillate and perfect flowers8. Staminate and pistillate flowers

Monoecious Fruit plants Unisexual (pistillate and staminate) flowers

are separate but borne on the same plant at different positions like in walnut, pecan nut, filberts, chestnut, banana, coconut and other palms

In most temperate fruit nuts (walnut and pecan nut) the staminate and pistillate flowers clusters are borne at different positions

Male flower(staminate) called as catkins and female(pistillate) flower called as spathe

Continued Pollination with the help of wind, though all nuts

are self fertile in many cases , yet pollination is not satisfactory, because some varieties fail to mature its pollen when the female flowers are receptive

Older plant grow higher number of catkins and pollen is shed for a longer period which makes pollination more satisfactory and result in better crop.

It has been recommended to grow new walnut near to old plantation to get early and satisfactory yield from them

Pseudo hermaphrodite Flower fruit plants

Their flowers are perfect having both male and female sex organs but either stamens or pistils are non functional and they behave as staminate or pistillate flowers such type of flowers are called pseudo hermaphrodite flowers

Unusual sex distribution in some fruit plant

Some varieties of Japanese persimmon present unusual sex distribution. Many of its varieties like costa , produces only pistillate flower year after year called as pistillate constants

Some varieties like eagle lake produces only staminate flowers called staminate constants

Some varieties produces only pistillate flowers in some season and both staminate and pistillate in other season called staminate sporadic

Abortion of pistils or ovules If fruit setting and development depend on the union of sex

cells, any factor which hinder the process of fertilization, would definitely result in unfruitfulness or in sterility

Any interference during flower stamen or pistil development is largely responsible for poor fruit set in many fruit plants e.g mango

In number of species and varieties the pistils and ovules appear to be normal but partial or complete degeneration in the embryo sac prior to its maturity may affect the fertilization process and ultimately in the fruitfulness of that species. However it may be noted the abortion of a plant of the ovules does not lead to necessarily to unfruitfulness

Pollen Importance Beach(1898) was the first scientist to

realize the importance of pollen viability in deciduous fruits

He concluded that on the basis of pollen viability, the varieties of American grape can be grouped into three classes self fertile, self sterile and partly self sterile

Thank you for your time