Today we will talk about Oranges. Orange is a citrus fruit popular for its tangy-sweet flavor. I think all of us know what an Orange is, but do you know how they grow? Oranges produce seeds that can grow into a new plant. This is the natural propagation method of Oranges along with all other citrus fruits. Although the rise of demand for seedless fruits leads to the development of Popular seedless Navel Oranges. They don’t contain any seed but Why? Have you ever thought Why do Some Oranges don’t have seeds? The simplest answer could be the demand that force cultivators produce such fruits. The technical explanation includes the inability of these citrus plants to self-pollinate. They can produce fruits without successful pollination and this flaw is always being exploited by the cultivators for commercial benefit. Interested in discussion then keep reading.
Check out my previous post: Will Grass Seed Grow if I just Through it Down?
Is Seedless Oranges Truly Seedless?
Most of These Seedless Oranges are truly seedless Although some of them may have traces of immature seeds. Navel oranges are one of a few true seedless orange varieties. They don’t have any seed in them. So you can’t find seeds to grow seedless navel orange varieties. Even if you find some, the chances of their viability as truly seedless is almost 0%.
You can look for names and probably some details about the oranges that you are buying in the store. Some of them indicate whether the fruit is seedless or not. Orange Fruits available for juice may have some seeds while those listed for raw consumption do not have any seeds. They are always seedless and most of them are truly seedless without any trace of an orange seed.
You can’t grow a seedless orange variety from orange seeds. Instead, you can grow them from cuttings, grafting, or layering developed from a parent seedless orange plant.
Also Read: Why Don’t Limes have Seeds?
Are Seedless Oranges Real?
Yes, seedless oranges are real. You can find several Organe varieties without any seed. Most of these varieties are subsets of Navel Orange Variety.
Regular oranges do produce seeds and they do so to maintain their heredity. It is not common for oranges to produce seedless fruits naturally although it is possible due to natural mutations.
Seedless oranges are real with variations in their types. Some of them are truly seedless while others may have thin seed formation. It usually happens due to the difference in the process of their development.
Almost every edible orange that you can find especially for salads and raw eating is seedless Navel oranges. Otherwise, oranges grown for juice do have seeds and they usually belong to the Valencia Oranges varieties.
Why are Some Oranges Seedless?
Some oranges are Seedless while others are not. There are quite a few reasons that may lead to the development of these seedless oranges. All of these are related to the demand. Cultivators grow these seedless orange fruits to fulfill market demand.
Seedless oranges are high in demand for all types of uses. Users prefer eating seedless oranges as they need not worry about the seeds. It is somehow easier and more comfortable to consume. Therefore the commercial benefits of seedless fruits give birth to most of these seedless oranges.
Sometimes oranges can forget to produce any seed naturally. This can happen due to natural mutation in some plants. It is a rare yet possible phenomenon.
Most oranges are Parthenocarpic just like other citrus fruits. This simply means that they can produce fruits even without successful pollination. Sometimes these plants produce flowers that are unable to self-fertilize hence they need another plant with a compatible genome structure. Altogether this condition helps cultivators to alter the formation of seeds. They just have to stop cross-pollination by preventing bees and butterflies with propper netting.
Check out: How Do Limes Reproduce Without Seeds?
Where do seedless oranges come from?
Most seedless orange varieties have a common parent i.e the Navel Orange variety. There are two separate origins that relate to the formation of seedless orange varieties. It first starts with a natural mutation in the plant and then selective breeding leads to the development of seedless oranges.
The History of seedless oranges dates back to the early 18th century. It was a natural mutation first observed in very few orange plants that produce fruits with small to no seeds. Further research and improvement in hybridization techniques enhance this particular character to produce a new orange variety with seedless fruit.
Genetic Study enhances our understanding of the development of seedless fruits. It shows that some oranges produce pollen with separate pair of gens that is incompatible with the ova. Hence these flowers are unable to self-pollinate. They can’t develop seeds Although they can produce fruits. The parthenocarpic nature of the orange plant helps cultivators to produce truly seedless oranges.
Can Seedless Oranges produce fruits with Seeds?
It is strange but true that seedless oranges can produce fruits with seed. You have to understand that these plants are not sterile. They stop seed development not because of their inability to do so but for the reason that we intend to not produce seeds. Orange fruits can develop without successful pollination. It is not seen in every variety although this phenomenon is very common.
It can Produce seed only after successful fertilization. Fertilization requires pollination that includes the transfer of pollen from the anther to the stigma of the flower. Here the main problem occurs, some of these plants produce incompatible pollen which is unable to fertilize the ova. So if you restrict such plants to self-pollination and prevent any pollinators to cross-pollinate then they will never produce seeds. They simply can’t fertilize with self-pollination.
Although if you allow these plants to cross-pollinate with the same species but not with clones then they will definitely produce seeds. You can observe this phenomenon with old seedless oranges growing among other citrus fruits. They occasionally produce fruits having a decent number of viable Orange seeds although they will not produce seedless oranges if grown.
Also read: Why is it Expensive to Produce Hybrid Seeds
Science of Seedless Oranges
The Science of Seedless Orange production is very interesting. There are two aspects of this explanation. First It can happen naturally due to mutation in the plant or any particular branch.
To understand this phenomenon we have to consider how a seed forms with fruits. It all starts with the pollination process. It requires the transfer of pollen grains from the anther to the stigma of the flower. These pollens develop roots to reach the ovary. They release two eggs to fertilize the ovum. These eggs fuze to produce the seeds and the ovary becomes the fruits.
Now in the case of Parthenocarpic fruits, they can produce fruits without successful pollination. So all it requires is to stop pollination and leave the fruits to develop without any seed. Orange being parthenocarpic has another anomaly that sometimes prevents it from self-pollinating. It usually occurs due to the dissimilarity in the genetic structure of the sperm or egger and the ovum. They become incompatible to fertilize hence the seed development stops.
Together these conditions restrict Some oranges to produce seeds. Now to manipulate these characteristics, cultivators prevent cross-pollination between similar species. They propagate Seedless oranges asexually through grafting or layering to clone the plant instead of allowing natural evolution to deal with this anomaly.
Chromosomal Disbalance is the root cause of anomaly that leads to the development of all Seedless Navel Orange varieties.
How do Seedless Oranges Propagate without Seed?
We can Propagate seedless oranges asexually with grafting or cuttings. They don’t produce seeds so you can’t grow these plants with seeds. That’s why we need some other means to continue their heredity. We can successfully achieve this with Stock Grafting or Layering Techniques.
Grafting and Layering are two very important and successful techniques to reproduce seedless oranges. Asexual reproduction has a great advantage for seedless oranges. They are parthenocarpic fruits and due to chromosomal incompatibility, they can’t self pollinate to produce seeds.
Therefore if you grow them asexually then each new plant will be a clone of the original plant. Hence they all will behave like one single entity and will never fertilize themself. This will reduce your effort with the prevention of cross-pollination. These techniques can help in increasing the yield of seedless oranges.
So what to do?
- You can buy grafts for local nurseries or grow a few in your garden. Grafting can be tricky although you can successfully do it with a few tries. take stem buds or apex from a seedless orange plant and fix it on a seedling. It will take time and effort and finally grow into a new branch. Remove all other branches and let only the graft grow as the orange plant. It will produce seedless fruits on maturity.
- Make layering in existing seedless orange plants. Simply make 1-inch slits in the skin of the stem. Remove the skin and clean through the white cambium. Wrap the open cambium with moist soil mix and cover it with plastic wrap. Let it develop root and detach the branch and transplant after 3-4 months to a new location.