Causes of unfruitfulness in fruits

Causes of unfruitfulness in fruits

All the fruit plant in an orchard will not bear equally at a regular interval and sometimes they fail to flower and fruit under similar conditions where another fruit tree bears heavily. This failure of the plant for setting of fruit may be attributed to unfruitfulness of that specific plant.

Fruitfulness is the ability of the plant to produce flower as well as fruit whereas; the inability is referred to as unfruitfulness/ barrenness. It is the most important and serious problem of the orchard. It makes the plant unproductive even after they attained the age to bear fruits. Its cause must be diagnosed or identified to reduce the loss to the farmer.

Causes of unfruitfulness:

Unfruitfulness in fruit plants is due to two important factors, they are the internal factors like Evolutionary tendencies, Genetic influence, Physiological factors etc and the external factors like environmental situation, pest and disease problem, locality or area where the orchard is present etc.

a. Internal factors for Unfruitfulness:

1.     Evolutionary tendencies of the plant: 

     During the course of evolution for better adoption of the specific crop there was occurrence of some characters, which leads to barrenness if proper care is not taken. Some of the characters are described below.

                     i. Monoecious and Dioecious nature: The plant with stamens and carpels in same or different flowers on the same plant is known as monoecious plant for example mango. When the stamens and carpels are present in different plant then the plant is called as dioecious plant like papaya. In Monoecious plant pollination and fruit set is not a problem due to self pollination. But on should be sure that there is proper availability of pollinating agents. In dioecious plant if availability of any of the pollen or carpel at definite time then there will be no fruit set.

             ii. Heterostyly : A condition in the flower where length of the style is different and cant be easily pollinated.

       iii. Dichogamy: the difference in the receptivity time of stigma and pollengrain. Protoandrous is the situation where the androcium or stamen matures first than the gynocium or stigma and in protogynous situation the gynocium ripen prior to the androcium. So there will be one time where the egg cell can’t be fertilized due to shortage of pollen grains.                           
     iv. Abortive Flowers or aborted pistils or ovules: It also causes unfruitfulness as there is flower and fruit drop in case of aborted flower or pistil or ovules.
     v. Impotence of pollen: Pollen viability determines the process of fertilization, which the first step of formation of fruit in many fruit plants. When the pollen is not a functional one then there is failure in pollinisation as well fruit set.

2. Genetic influences:  Self sterility is a condition determined by the inheritance received from the parents but can develop in favourable environment which affects the off springs as well as hybrids. Incompatibility is the major reason for barrenness in fruit plants.

3. Physiological influences:  The different physiological causes like Slow pollen tube growth, Premature or delayed pollination, plant nutrient status, positions of fruit setting, hormonal imbalance etc make the plant barren either at the primary or latter stage of fruit growth.

b.  External factors causing unfruitfulness:

 Some of the external sources act as the cause for unfruitfulness in fruit crops and they are as below:-

i. Nutrient supply: During floral development and fruit growth stagethe plant needs much of the nutrients and if shortage of essential nutrient will be there the plant may bear flower but they can’t develop mature fruit.

ii. Pruning and Training: It is a regular practice to maintain the bearing area of the tree. Pruning should be done at proper time and desired quantity to maintain the plant in a fruitful condition.

iii. Locality: It means the suitability of climatic condition for a particular crop.

iv. Season: Some cultivar bear earlier in the season and some in latter part and hence proper measures should be taken for pollination.

v. Temperature: High temperature at flowering dries up stigmatic secretion and prevents pollination.

vi. Moisture: Proper moisture level should be there to maintain the cell rigidity and control fruit drop.

vii. Light: After completion of the photoperiodic requirement for specific plant it will flower.

viii. Pests and diseases: Sucking insects like bug, hopper, whiteflies etc suck the succulent tissues of the flower and make it dry. After flower anthesis stage there shouldn’t be use of any pesticide which might reduce the pollination and fruitset.

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