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Quick and Simple step to Hibridize Adenium by Lap Huynh*

The thought of hybridizing Adeniums must have crossed one's mind at one point to another. The thrill in creating new varieties that display new and exciting colors is perhaps what makes everyone so tempted to try their hands on hybridizing adeniums ! That's not all – the process of getting the fruit to form and mature as well as raising the progeny to maturity so they bloom can be so challenging and fun. The sense of achievement one can derive from the entire process cannot be dismissed. We will leave out "selfing" since the experts believe you need 2 adeniums to get seedpods. You can do crossing, where you take the pollen from the flower of another plant and put it into another plant's flower. Most importantly, you need not be an expert to start crossing your Adenium plants. Follow the steps detailed in this article to get started. Once you are confident, move on to the more advanced methods. Eventually you will stick the one that you are most comfortable with! After pollinating your plants, do feed them well. Plants tend to abort their fruits if they feel that they are unable to support them. A water-soluble fertilizer with an NPK ratio of 20-20-20, used at 1/4 to 1/8 of the normal strength at the recommended frequency would be ideal.

For Beginners:
Pick a flower that has been opened for 3 to 4 days and cut it vertically in half to study its structure (Fig.1). 

Fig. 1

Remember to equip yourself with a good magnifying glass!
Using a magnifier, look for the three most important structures that you need to know to do 
hybridization – pollen, gel cap and the receptive surface.
Look for pollen-laden anthers that are found inside the cone of the flower. These are the structures 
that hold the “white to light yellow, grainy, look like microscopic fish eggs in masses” pollen. Some 
Adenium produce tons of pollen whereas some others, none. The reason we use older flowers is 
because the anthers would then be better separated from the stylus, making it easier to see the 
receptive surface. The pollen will also be more mature.
Next, look for the gel cap in the flower. The whitish-looking gel cap (style head) is just below the pollen. 
It covers a structure called the stigma. It is there to block its own pollen from falling into the stigma. 
In short, it prevents self-pollination. 
Below the gel cap is the receptive surface for pollen. It is actually the underside of the style head. 
Besides the gel cap, there are two “fake” rudimentary stigmas sitting on top of the real one, that why the 
receptive area is found so low in the style head.(G. Rowley, Adenium Handbook, 1983). Mother Nature 
seriously means no to self-pollination! We will come back to  another very clever use of the “sticky gel” in 
the Advanced Technique. 
You will need the following: a nail clipper, some toothpicks, Scotch tape, a good head lamp to put light inside 
the flowers while  leaving your hands free.
Getting Started:
1.       Pick some flowers from your favorite plants to harvest pollen. Pick up the pollen using a toothpick, which 
has its tip wetted. You may want to use a magnifier to make sure the pollen are on the toothpick till you can 
see pollen (masses) with naked eyes.
2.       Open the receiving flower by cutting its corolla (throat) to ¾” or 1.5 cm and peeling it backwards [Fig. 2]. 
3.       Clip off ½ or the whole anther (the side of the cone) to expose the gel cap and the receptive surface.
4.       Gently tap the tip of the toothpick on the receptive surface of the receiving flower to deposit the pollen there.
5.       Close the flower by taping it with sticky tape (Fig.3). 
You are done. If all went well and correct, you will see seedpods in 7 to 11 days. Seedpods usually develop in 
pairs and grow outwards from the base and look like horns.

   

Fig. 2

Fig. 3
For the more experienced…
Hopefully you can visualize the receptive surface and the gel cap inside the cone of a flower by now. In this procedure, 
take a fine tip brush size 3/0 or 1/0, instead of a toothpick, to collect and transfer the pollen.
Below are the steps you have to take…
1.       Prepare the flowers for pollen and make a cut that is ¾” or 1.5 cm long on the throat of the receiving flower. 
Wet the tip of the brush and pick up the pollen. Check for pollen with the magnifier.
2.       Squeeze the base of the receiving flower to open up the cone. This will expose the receptive surface and 
the gel cap. In fresh flowers, you might have to pry open one side of the cone using the tip of a toothpick [Fig. 4]. 
3.       Place the tip of the brush that is laden with pollen below the receptive surface and  brush the tip up. 
4.        Close and tape the flower with Scotch tape.
After practicing the above two methods on 5-10 flowers, it is time to move on. 

Fig. 4

Now let’s set two adeniums (A &B) on a table. Do not cut the corolla, just pull the filaments (tails) out then squeeze
the base of flower A  to collect the pollen, transfer to and pollinate flower B , at the same time, take the pollen out from 
flower B and pollinate it back to flower A ! You still have the “intact” flowers to enjoy! This is actually the method 
commonly used by Adenium growers worldwide for decades to create thousands of new hybrids.  
Switching on the Advanced mode…
Here, we are going to mimic Mother Nature! By now, you probably have noticed that there are five dark lines in the
throat of a flower. Each of these markers lead to an opening at the base of the cone [Fig. 5]. A natural pollinator such 
as a moth  will stick its proboscis through one of these openings to reach for nectar, yet at the same time, without knowing it, 
help to pollinate the flower.

Fig. 5

To make a proboscis, we would need a thread from the hard shade cloth. Cut the thread into pieces about 2 inches long 
and then tape each to a toothpick, leaving 1” of the thread free at the end. Stiff horse hair or fishing line also can be used. 
Scrape the fishing line with a pocket knife to give it a rough surface.
Acting like a pollinator…
1.  Hold the flower still and insert the thread into one of the holes at the base of the cone, let it drop to the bottom 
[Fig.6, A]. Work the thread up and toward the center [Fig.6, B]. Move the thread up and down ½” while rotating it. 
After about 10 seconds, pull the thread out through the top of the cone. In this motion, the “proboscis” is soaked with 
“sticky gel” and picking up pollen on the way out. Check for pollen sticking around the ½” mark from the tip. If there is 
pollen, move to the receiving flower.
2.  Hold the receiving flower still and repeat the above step.
This method has been pioneered at Arid Lands Nursery.

Fig. 6

Starting around week 4th, seedpods will grow very rapidly and mature in 3-4 months. When seedpods stop growing, 
you might want to tie them loosely with plastic coated wire to keep the seeds from flying away (Fig.7, 8). Seeds must be air 
dried well and sowed as fresh as possible.

Fig. 7

Fig. 8

Two day old flowers seem to be best suited for hybridizing. The efficiency of any technique above is in 90-95% range 
if you take time and repeat the pollinating steps several times. Mark each pollinated flower with permanent markers 
before moving to next flowers, or use tags with strings to identify date, male and female parents.
Reference:
-          Jaya Mathai: Hybridization of Adenium; ISOCS Journal, Jan-March 2005, pages 8-11.
Acknowledgments :
The author would like to thank the following for editing this article:        
-          Thomas Longbrake, College Station, TX.
-          Art Kavan, Tucson, AZ.
-          Wilson Wong, Green Culture Singapore, www.greenculturesg.com 
( * ) : About the author:
-          Member of The Houston Cactus & Succulent Society.
-          Officer of The Plumeria Society of America (Secretary , 2003 ; Membership Chairman, 2004-present)