Woody Agriculture Weblog
The Future of The World Is Nuts!(TM)
A Possible New Avenue For Hazel Tissue Culture/Apomixis/Propagation
Saturday, Sept. 4, 2004.
Working today on marking hazel plants for harvest, and doing annual crop data collection, I came upon some extraordinary phenomena in some of the hazel bushes.
For several years, I've been seeing hazel clones in the greenhouse set "seed" in some of their catkins- but only when I successfully pollinated the "transsexual" catkins that developed under the abnormal annual phenology in plants grown all year in the greenhouse.
greenhouse catkin 2276.JPG.
What you are looking at above is a macro photograph of "nutlets" developing in a pollinated, greenhouse grown, hazel catkin; previously male. The little green "banana" -looking things are possibly naked "embryoids", according to the independent opinions of myself, Paul Read, and Mehmet Nuri Nas.
For several years now, we've very occasionally run into odd, extremely underdeveloped "nutlets" in the field; far out of synch with the rest of the crop. They were so rare I did not know what to attribute them to; but it now appears we started seeing these at the same time we first started to see the appearance of "big bud mites".
Last I knew, two eriophyid mites, Phytoptus avellanae and Cecidophyopsis verminiformis, were known to infest hazel buds; causing the buds to swell and usually abort. In the last 2 years, the prevalence of the mites here had increased dramatically (though we have plenty of bushes essentially unaffected). Having examined and rated hundreds of hazel bushes for bud mite problems, I can say with certainty that the mites will not only infest vegetative buds, but also the male catkins; causing various kinds of deformities.
Today, however, I found this in the field-
BB nutlets 5368.JPG
And far from it being the only one; in one portion of a particular row, every other plant (half sibs) had many of these. This is a hazel catkin, apparently infested with bud mites- which is looking a lot like the "nutlets" generated in the greenhouse.
I sacrificed a few to open them up, and see whether the inside structure was simply random tissue, gall-like, or whether it actually resembled a nut-
BB nutlet embryos 5374.JPG
It does, in every detail. There is a hard nut shell, a husk, an interior pith superficially identical to the pith in immature nuts, and... what looks an awful lot like embryos; exactly where they should be.
If these are indeed embryos or "embryoids"- the probability is extremely high that they are apomictic embryos, produced as a by-product of whatever plant hormones the bud mites are using to divert the resources of their plant host.
Some observations and suggestions:
a) I have at least 50 of these nutlets available right now. However they are somewhat fragile in their attachment to the plants; and we are picking nuts; they will not last.
b) These embryoids are inside a shell; and likely as nearly sterile, in terms of microorganisms, as any hazel tissue ever is; this could make culture much easier.
c) If these are what they look to be, embryoids; it should be possible to identify the plant hormone(s) being used by the mites; and use them to generate apomictic embryos on demand; from most hazels. This could be an extremely powerful new technique for propagation.
Some possibilities:
whatever is causing this phenomenon might well be mites different from those suspected; or not mites at all; or something secondary to the mite infestation.
there might be novel "plant hormones" involved.
mutation rates in this process are unpredictable until tested.
Last update: Sunday, September 5, 2004 at 8:35:26 AM.
