When growing tomato plants at home, the biggest question that comes to mind of gardeners is do tomato plants self pollinate or do I need to do something for pollination to take place.
Tomato plants can self pollinate but you can also follow the hand pollination method to ensure ripe and red tomatoes on your tomato plant.
Are you indifferent to these terms, read below to gather detailed knowledge about self pollination and hand pollination in tomatoes.
Also Read: How Long After Flowering Do Tomatoes Appear?
What is Self Pollination?
Self pollination is a type of pollination in which pollen from the anther of a flower will be transferred to the stigma of the same flower.
Fertilization in plants happens with the help of pollination. There are two methods of pollination- self pollination and cross pollination.
In self pollination, the fertilization takes place in the same flower. Pollens from the anther of the same flower get transferred by various methods to stigma of flower. This type of self pollination is referred to as autogamy. These flowers that self pollinate are called hermaphrodites. A hermaphrodite is a flower with both male and female reproductive organs present in it.
To add to this, in self pollination, pollen can also be transferred from one flower to another flower but they should be belonging to the same plant. This type of self pollination is known as geitonogamy.
Stamen is male reproductive organ that produces pollen grains while stigma is the female reproductive part producing eggs.
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Advantages of self pollination
- The purity of race or parental characters is maintained in the plant.
- Self pollination is performed to maintain pure lines. This is done to perform hybridization experiments later on.
- There is no need of large pollen grain production in self pollination.
- They also do not need to develop devices for attracting insects.
- Seed production is ensured in case of self pollination.
- Also, this type of pollination removes any bad recessive characters.
Are Tomatoes Self Pollinating?
Tomatoes can easily self pollinate. They just need the right conditions for that to happen. There should be appropriate temperatures, wind or insects to transfer pollen from anther to the stigma of the same flower or flowers on the same plant.
Why Are My Tomatoes Not Setting Fruit?
There could be a few reasons behind no fruits on tomato plants including insufficient pollination, too much heat, less fertilizer, etc.
Let’s talk about insufficient pollination-
Tomatoes are self fertile so they perform self pollination. Presence of bees, wind, improves pollination chances. But if there is a lack of such conditions, you can do pollination by yourself.
Opt for artificial pollination by your hand. Just shake plants a little to let pollen disperse and reach stigma. Do it 2-3 times a day to ensure pollination takes place.
Also Read: Are Cucumbers Self-Pollinating?
How to Self Pollinate Tomato Plants?
Cultivated tomatoes have complete flowers with both make and female reproductive organs. So, they are self pollinators. In the process of pollination, pollen is discharged from the pollen sac onto another flower. They reach to the top of the stigma of flowers. The top of the stigma has a sticky surface which lets pollen stick to it.
Then these pollen grains germinate and form pollen tubes to reach the ovary of the flower where fertilization will take place. After fertilization, ovules are produced. The fertilized ovules become seeds and the ovary forms the fruit. The fruits produced are genetically identical to the other plant.
The method of self pollinating of tomato plants happens through hand pollination.
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Do Tomato Plants Need to Be Pollinated?
As mentioned earlier, tomato plants being self pollinators, they do not need to get pollens disturbed through hand pollination. But if there is lack of humidity, wind or any insects that can carry out pollen transfer then just shake plants a little to distribute the pollen.
How to Hand Pollinate Tomatoes?
Hand pollination is a technique that is used for breeding new varieties of tomatoes with desirable characters. These desirable characters include plant vigour, disease resistance, uniform quality of fruit and plant growth. In case of hand pollination, it is important to select varieties that are true.
Hand pollination is an easy and effective method of pollination. Pollen grains are normally shed by plants from morning to afternoon. Midday is the best time for pollination to take place.
Warm and sunny days when humidity levels are low are the most ideal conditions for hand pollinating.
There are some popular techniques used for hand pollinating. You can use a vibrating device like a toothbrush just behind the flowers. It opens the flowers and shakes them a little to distribute pollen grains on the plant.
While the other method is collecting pollen grains in a container and using cotton to rub it on stigma.
Hand pollination can be done every 2-3 days to ensure it takes place. When plants pollinate successfully, then they will wilt and begin fruiting.
Also Read: How to Pollinate Eggplants?
Hand Pollination- 4 Ways
#1 Shake them a little
Simply shaking flowers a little sets a breeze which lets pollen detach and move to stigma. Gently tap the top of the flowers a little. Also, you can flick the stems of flowers.
#2 Use brush
A small art brush can be used to perform the task. Gather pollen by rubbing in on anther and then distribute it over stigma. This is similar to nectar- gathering insects.
The bristles of brush make pollen cling to it. It is advised to use a natural brush instead of plastic one.
Lift the flower up gently and rub brush back and forth inside petals, on pistil and on stigma to collect and transfer all the pollen.
To avoid cross pollination, the brush you use should be washed with isopropyl alcohol to clean it thoroughly. Also, you can use different brushes for different tomato varieties.
#3 Cotton swab
These are another very effective tool for transferring pollen. Spun cotton on cotton swabs gently collects pollen without damaging them. You can follow the same method as done with the brush.
Or collect some pollen in a small dish and use cotton swabs to apply it on the stigma of the flower.
#4 Battery operated Toothbrush
This is the best method for collection and transfer of pollen grains. It is an easy, effective and fast method.
The vibrators in the toothbrush are effective in detaching pollen from the anther. It mimics buzz pollination and anthers release pollen. Vibrate toothbrush on base of the flower or on the flower stem.
Now, here is a guide for hand pollination of tomato flowers for breeding and production of seeds.
#1 Selection and emasculation of flowers with pollen on mother plant
The best flowers for collection of pollen are those which are newly formed and unopened buds. The ones that will open in 1-2 days should be selected for this process.
To guess when flowers will open, know that tomato flowers clusters open in sequence. If a flower opens today, the second will open the next day and the day after tomorrow. So, you will know when one flower opens, next will follow.
You can easily remove anthers by hand or using forceps. For this, hold the plant from its base or pedicel and just pull anthers out. It is advised to remove open flowers from emasculated flower’s vicinity. This is done to stop pollen exposure for the emasculated flower. You can wrap a twist tie around the stem to tag it.
Emasculation needs to be performed at the correct time. Otherwise, there are possibilities that the pistil of the flower is damaged or not mature enough. Stigma might not be ready with pollen yet. If it is done too late, pollen might have shed upto that time.
#2 Pollen collection and drying
Open dark flowers should be chosen for anther removal. When humidity is low, pollens can be easily removed from flowers without detaching them from the plant itself. You can use a dissecting needle or scalpel to cut anther cones and use tools to remove pollen.
Humid conditions make it difficult to remove pollen from another. They do not release easily. For this, flowers should be kept under room temperature and left to dry for 1-2 hours.
If this doesn’t work, simply pull anthers out of the flower and leave them under the sun or incandescent lamp. After drying, anther’s split and release pollen. Tap the flower a little for easy removal.
Pollen can be stored for about 1-2 months. But the conditions should be maintained like dry.
#3 Pollination of stigma
After 24 to 72 hours of emasculation, pollination is performed. Early morning time is preferred for pollination. Take stigma and dip it in pollen. You can use a small brush or dissecting needle for this.
Pistil can very easily get damaged in this process. So, this process should be undertaken carefully without performing any unnecessary task.
Fertilization happens in around 24-50 hours after pollination. After a couple of days, there is the appearance of a swollen ovary that confirms fertilization.
It is quite necessary to maintain optimum conditions at time of tomato flower pollination. The temperature conditions must be between 75-80F. Humidity levels can be 70 percent air relative.
If in the morning before 10 am, the temperature rises over 90F blossoms will drop. Night temperatures below 55F or above 75F damage the pollen grains. Thus, there would be no formation of pollen tubes.
How Often Should I Hand Pollinate?
Hand pollination can be performed every three to four days in afternoons. Open every blossom and repeat the process of pollination every couple of days. It should be done until every flower on the plant gets fertilized. Fruits will begin forming when flowers wilt.
Advantages of Self Pollination over Cross Pollination
Self pollination refers to transfer of pollen from another of a flower to stigma of the same flower or flower on the same plant.
On the other hand, cross pollination is a type of pollination in which pollen from another of a flower is transferred to the stigma of another plant or variety.
There are various advantages and disadvantages of both types of pollination.
Advantages of self pollination
- It helps in production of large number of individuals
- It takes less time to self pollinate.
- Advantageous traits do not get lost because fruits produced are genetically identical to the mother plant.
- There is very less chance of failure pollination because of flowers being present in such close proximity.
Disadvantage of self pollination
- New and useful characters do not get introduced in self pollination.
- Decreased immunity for diseases.
- Variability and adaptability to various conditions gets lowered.
- Prolonged self pollination reduces vigour and vitality.
Advantages of cross pollination
- It brings variation in the gene pool.
- It gives more survival advantage to the plants.
- Seeds are healthier and more viable.
- Germination capacity of seeds is also high in cross pollinating varieties.
- There is a possibility of forming new varieties of species.
Disadvantages of cross pollination
- More time and effort is required.
- Natural process becomes delayed.
In self pollination, it doesn’t take much time. Flowers are present on the same plant. You just need some right tools to transfer pollen from one flower to another. Efforts are much reduced in case of self pollination.
But if you consider cross pollination, it takes more time to collect pollen from a different variety and then transfer it to others. There is huge effort required to find out correct varieties that should be used in the process. It needs to be carefully thought about.
Cross pollination is done to get specific results. So, you need to figure out which type of varieties needs to be pollinated to get desired results. Also, it is not necessary to get success in the first go. While, in self pollination, fruits are genetically identical to mother plants, so there are very less chances of failure.
You might have a useless variety of tomatoes with cross pollination that just wastes your time and efforts.
Next, large numbers of individuals can be produced in case of self pollination which is hard to perform at one go in cross pollination.
There is only a specific amount of fruit produced in the F1 generation. It requires time to produce a large number of fruits of the same variety.
Follow this detailed guide on self pollination and hand pollination to produce an amazing and huge number of red, ripe tomatoes at your home.