Hand-pollinating Dioon mejiae
by Jody Haynes

As my cycad interest has grown in recent months, I have felt the need to learn more about anything cycad, from propagation to culture to hand-pollination. Therefore, when I noticed a female cone emerging from a large Dioon mejiae here on the grounds of the Tropical Research & Education Center a couple of months ago, I figured I better learn how to pollinate Dioon cones and establish a contact for pollen. 

I made arrangements with folks at Montgomery Botanical Center (MBC) and Fairchild Tropical Garden (FTG) to begin assisting in their hand-pollination programs. I then wrote to Tom Broome and asked him when I should expect the cone to be mature and he said mid-November or so. So I figured I had plenty of time to do what I needed to do to prepare for hand-pollinating this cone. I then talked to another friend, Ellis Brown here in Miami, who knew of a male with cones emerging and I asked him to save some pollen for me because I would be needing some in November. He told me "no problem."

Well, needless to say, when I saw the cone with its lower-most scales open last Wednesday (13 October), I was frantic. The cone was mature weeks earlier than expected; due to various unforeseen crises, I hadn't made it to MBC to pollinate any cones; and I hadn't heard anything from Ellis regarding his pollen. I immediately wrote Tom and said the cone is receptive and "what should I do"? He told me that the cone will be receptive for five days and that I needed to do something real quick as we didn't know which day of the five it was. I called Ellis, who told me that none of his cones were yet mature. So then I called MBC to see if they could get me some D. mejiae pollen. I couldn't reach anyone until Thursday (14 October) morning and then they weren't sure if they had any pollen for that species.

Just as I was getting ready to leave to take my boss to the airport Thursday around noon, the phone rang... It was Judy Kay from MBC saying she had plenty of pollen and that I was welcome to stop by and get some. So on my way back to work from the airport, I made a small detour to MBC and acquired the much-needed pollen. I headed off back to TREC on a quest to hand-pollinate that cone. Judy gave me some pointers on how to pollinate it and I had seen some photos of Larry Kraus pollinating a Dioon cone at MBC, so I figured I could at least give it a try.

Below are some photos of me hand-pollinating my first-ever cycad cone. If I didn't know better, I might think I actually knew what I was doing!

This is the receptive female cone of our Dioon mejiae. You can just barely make out the loose scales at the bottom.

Numerous techniques have been tried for hand-pollinating Dioon, but Larry Kraus has perfected the art. The first step in Larry's procedure is to completely remove the top "plug", exposing a narrow, tubular chamber lined with ova that extends from the top to the bottom of the cone. If you look closely, you can see an ovum that remainded attached to the plug when I removed it.

This is a shot looking down into the cone.

Next, I drew up some pollen solution into a pipette and slowly squirted it down into the cone. I mixed two packets of pollen in about 30 ml of water.

If everything is done correctly, the pollen solution will dribble out the bottom of the cone (right).

I pollinated the cone in this way on Thursday, Saturday, and Monday--every other day. Now, I guess I'll just have to wait and see if my first hand-pollination attempt was successful. Unfortunately, the problem with Dioons is that the seeds take 18 months to mature. I'll post an update in March, 2001!

Acknowledgments
I would like to thank Tom Broome, Ellis Brown, Judy Kay, Terrence Walters, and Larry Kraus for their assistance. Also, thanks to Ian Maguire of TREC, who took the digital photographs.

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