Thursday, 19 January 2017

Albino corn, beautiful but useless

Albino Corn - beautiful but useless
Look how pretty my albino corn plants are!  They look amazing.  It is too bad that they have to die. 
Albino corn seedling, such a pretty little plant
I planted sweet corn seed this year from seed that I have saved, I had great germination rates.  Sweet corn seeds, according to the internet, generally has around 75% germination, super sweet generally has far lower than that.  Mine has always germinate well above that, even several year old seeds tend to germinate better than that.

This year, I have had some albino corn seedlings emerge.  If you take those out as they will not survive (and also do not include the several partly albino plants that possibly would survive but I have culled as they are weaker) I had over 87% germination this year.  Not too shabby.

Albino sweet corn seedling

Why albino plants die
It is possible to keep these albino plants alive for a while, it is even possible to grow them long enough for them to mature and produce seeds, but it is not worth the effort.

I could grow them in tissue culture, I could feed sugars through the leaves every other day, but without me they would die fast.  Albino plants can not produce chlorophyll, non-parasitic plants need chlorophyll to produce energy from the sun, without chlorophyll they die.  If they are not green (and are not grafted or parasitic) then they can not survive without a lot of effort from me.

On top of issues with not being able to photosynthesize, albino plants also tend to burn in the sun.  The chlorophyll in the leaves help to protect them from the sun.  Some variegated plants do not cope in full sunlight for this reason.  Variegated plants also tend to be weaker due to the reduced amount of photosynthesis that each leaf can perform.

Albino Corn
What causes albinism in plants
Albino plants can be caused by several things.  It can be environmental, various poisons can cause high rates of albinism in plants.  If this is the case you generally see a lot of albino plants germinate close together.  This is not the case here.  More commonly albinism is genetic, it can either be through a random mutation or the albino genes can be in high concentration in the population.  Often older seeds have a higher percentage of albino as the genetic material has degraded slightly.  Sometimes, if seed is stored incorrectly it can suffer genetic degradation.  Wide crosses, such as interspecific crosses tend to increase the number of albino seedlings as can anther culture and double haploids and a few other things.

I have seen albino corn in the past, but never from this variety, so I am hoping that the gene is not present in the population in high amounts.

I have heard various wild and unsubstantiated claims about one of the initial parents of this variety.  I never took much notice of them until now.  I had been told that one of the parents, a landrace corn, was often crossed with some of the wild teosinte (most likely Zea mexicanicana or possibly Zea parviglumis) to increase its vigor.  If that is true, there is a wide cross which may have caused albinism in this variety.

Albino corn seedlings, partly albino corn seedlings, and normal green corn seedlings
If this is not from random mutation is it possible to remove albino genes from this population?
I am wondering, if albinism is present in this variety, is it even possible to remove the gene?  Being a recessive gene, and considering how corn pollinates, unfortunately I don't think so.  People have been culling black sheep for centuries, yet they still turn up every now and again.

According to the University of Oregon's photosynthetic mutant library, one of over 600 genes could be broken, each with 3 to 4 mutant alleles.  Even if I knew which gene was broken I don't think I could remove it from the population.

Considering that I have grown this variety of corn for years and this is the first time I have seen albino corn seedlings I don't think I will have too many problems.  I had a few partly albino plants which could have survived, and removed them so their genes would not be passed on.  I cull pretty hard.  I have also asked a few people I sent seeds to if they had any albino corn and none of them did, so hopefully I won't see much of this in the future.

Where to get albino corn
Some laboratory supply places overseas sell albino corn seed, it is usually F2 cross with green corn to show basic dominant/recessive traits.  I am not sure if anywhere in Australia sells them and it is not possible to import corn seed.  To be honest, I don't see why anyone would really want albino corn seedlings, other non-lethal traits can be used just as easily to show inheritance patterns.

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