Pollination is the process that changes a flower into fruit by transferring pollen from the male part of a flower to the female part of another flower. However, this isn’t always the way Orange trees produce fruits because these subtropical trees set fruit by both sexual and asexual means.
Types of Oranges according to Fruit Development
Studying standard-size and dwarf orange trees’ anatomies has given us information that orange flowers have both male and female parts, making an orange tree self-fertile and able to produce fruits through both asexual and sexual process that requires pollination and fertilization. So what is the difference between the two processes?
- Sexual – The most typical method of pollination among citrus trees like oranges is done through insects like bees and wasps. The insects get drawn to the sweet-smelling blossoms and enter the flower to collect nectar. As the insects leave the flower they unknowingly carry pollen with them and transport it as they move from flower to flower. A gust of wind and other insects like thrips can also carry pollen grains from one flower to another and can help with pollination. Fruits set through pollination and fertilization, like the Valencia Orange tree and Honeybell Orange Tangelo hybrid tree, can contain seeds. Take note though that the Valencia Orange tree is self-pollinating and can bear fruits without the help of another orange tree but the Honeybell Orange tree is not and has to be cross-pollinated with compatible cultivars for good fruit set.
- Asexual – Certain types of oranges like the Cara Cara Navel Oranges and Washington Navel Oranges are parthenocarpic. This means that fruits will develop without pollination occurring. However, since the fruits developed without the use of embryo or endosperm, the resulting fruits are seedless and cannot be used for natural propagation.
Orange Tree Pollination
Most orange trees, including Oranges Navel and Valencia, are self-fertile and do not need bees to pollinate and set fruits. However, fruit set and production can significantly increase if pollinating insects like bees are utilized. One experiment done on tree pollination showed that isolated orange trees can only produce 35% of the normal production compared to orange trees pollinated with the help of bees.
But what do you do if you do not have any pollinating insects to help you increase fruit set and production? Another way to pollinate a standard-size or dwarf Orange tree is by manually transferring pollen by hand. Hand-pollinating Orange Navel and other orange cultivars is easy and cheap. The process only requires a soft paintbrush or cotton swab that you can use to harvest and transfer pollen with. All you have to do is collect the powdery grains on the end of the flower stalk by gently swabbing or brushing a bloom and then moving on to the rest of the flowers and swabbing them with the same brush or cotton swab. Once pollinated, it would take five to 18 months depending on the orange tree cultivar to produce fruits.