Breeding tomatoes for the home gardener

[Stepheninky]

http://tomatoprojects.blogspot.com/2...s-at-home.html

Just put together a blog post on how to make crosses for the home gardener would love it if anyone would check it out and give me some input such as anything I might have left out or did not make clear.

I tried to make it as un technical as I could.

[heirloomdaddy]

nice. Great pictures and explanation!

[beefyboy]

Great Job! I have wanted to do this for a few years now and was hoping to find something like what u just did, thank you!!

[Stepheninky]

Thanks for the great feed back so far. One suggestion that I received was to add some step by step photos which I will try to do sometime this upcoming season.

Over all feed back has been really positive. So again thanks

[b54red]

How long is the pollen good for?

[Stepheninky]

Originally Posted by b54red

How long is the pollen good for?

Short answer is 3-5 days The recommendation in my article of 3 applications is not just based on pollen life but also due to bloom stage. The bloom stage at time of emasculation is still juvenile but should reach full bloom stage in 3 days or so. So the recommendation is based on the best chances timing wise to make the cross.

Long answer:


Storage life of tomato pollen.

McGuire. M. C.
As part of a progran of hybrid tomato seed production at the University of California College of Agriculture at Davis, the longevity of tomato pollen was tested under various storage conditions. Pollen was collected by means of a buzzer device similar to that described by Cottrell-Dormer (1945). In a few minutes this collector can collect enough pollen to supply a worker all day. The question naturally arose whether pollen could be safely used all day, or perhaps longer.

A preliminary test using the parents involved in the hybrid cross Pearson (ms2) x Pennheart was made.

It was found that pollen stored in a open vial in the full midsummer sun can still set a fruits on the third afternoon after the morning of collection. No fruit was set later by this pollen.

Other lots of pollen, stored under various conditions, produced fruit a much longer period. That stored over CaCl2 in a refrigerator produced fruit on 50% of flowers pollinated(five out of ten flowers) - )35 days after collecticn.

A more careful test was made the following year, using as female plants San Marzano (ms9) and as pollen parents a double-haploid line of San Marzano (2.72).

A quantity of pollen was collected three months before the start of the test, in order to lengthen the effective time span of the experiment. Each of the subsequent batches of pollen was collected on a single mourning andthoroughly mixed before dividing into storage lots. Three such collections were made, six days apart, the collections being kept separate in storage. This was done to reduce the effect of random fluctuations of weather by summing results of each storage condition at given pollen ages.

Storage temperatures were 0 deg., 10 deg. and 20 deg. C. At each temperature one lot of pollen was stored in loosely-capped vial, another in a sealed vial containing CaCl2. Control pollinations with fresh pollen were made each time any experimental pollinations were made. Precautions were taken te reduce the effect of variation between female plants.

Pollen viability was measured as percent of flowers that set fruit, and as number of seed per fruit. It may here be noted that this is an absolute measure of the effectiveness of pollen, not achievable in germination tests in vitro. Ten flowers were pollinated at each treatment with each lot of pollen. Pollinations were at three-day, intervals for a month, then weekly for two months, then monthly until the oldest pollen was a year old.

At each temperature pollen stored in low humidity (over CaCl2) produced fruit and seed long after that in high humidity (loosely capped vial). The lower the temerature of storage, the higher the life of the pollen. All samples retained their ability to stain in acetocarmine reguardless of their capacity to produce fruit.

Decline of ability of a given sample to set fruit and seed seemed parallel, though many samples set a few parthenocarpic fruits before complete failure.

Pollen collected during a period of unfavorable weather (hot and dry wind) had a much reduced viability both initially and in storage life, which was comparatively short. Ovules (or ovaries) also showed reduced fertility during unfavorable weather.

Pollen stored under the best conditions of the experiment (O deg. C. and low humidity) produced fruit after a year in storage but the practical limit for seed production appears to be six months.

[Qweniden]

Thanks.

I have a couple questions.

Lets say you have a plants P1, P2 and P3. All three tomato plants look totally different.

Lets say on one flower on P1 you cross P1 with P2. And then on another flower on P1 your cross with P3. Assuming pollentation works will you have two different looking tomatoes on the same plant from the two different crosses?

[Stepheninky]

Originally Posted by Qweniden

Thanks.

I have a couple questions.

Lets say you have a plants P1, P2 and P3. All three tomato plants look totally different.

Lets say on one flower on P1 you cross P1 with P2. And then on another flower on P1 your cross with P3. Assuming pollentation works will you have two different looking tomatoes on the same plant from the two different crosses?

I do not really follow:

If I cross two tomato plants the fruit does not change from that of the mother plant.

Now if you are saying 3 plants P1 x P2 and P1 x P3 will the offspring of those seeds when grown out be different ? If three varieties are used will be different then yes.


Other wise please re state the question as I am not clear what you are asking.

[Qweniden]

Originally Posted by Stepheninky

If I cross two tomato plants the fruit does not change from that of the mother plant.

Ok I think that answers my question. So if I have a Prudens Purple and put Green Zebra pollen on it, the fruit of that particular pollenated flower will still look like a Prudens Purple? But the seed from that fruit will produce the F1 Hybrid?

I hope I stated that clearer.

[Stepheninky]

Originally Posted by Qweniden

Ok I think that answers my question. So if I have a Prudens Purple and put Green Zebra pollen on it, the fruit of that particular pollenated flower will still look like a Prudens Purple? But the seed from that fruit will produce the F1 Hybrid?

I hope I stated that clearer.

Thats it. Thats why you have to mark the stem with a lose string etc... ( I use colored cable ties that I do not tighten up that way its color coded)

[matilda'skid]

I hadn't thought of making my own hybrid F1 seeds and saving them. It seems strange that crossing the same two varieties gives the same hybrid. I guess I am used to dogs and cats which turn out all sorts.

[frogsleap farm]

Originally Posted by matilda'skid

I hadn't thought of making my own hybrid F1 seeds and saving them. It seems strange that crossing the same two varieties gives the same hybrid. I guess I am used to dogs and cats which turn out all sorts.

Tomatoes are largely self pollinated, so "OP"varieties are inbred lines. A hybrid between inbred lines gives a very uniform F1 hybrid. Dogs, cats, and many plant species are "outcrossers", and hybrids between non-bred lines will give an array of F1 progeny.

[Stepheninky]

Added a Youtube video to the blog explaining the cross. Figured it will be easier for some to see it being done.

[emzybo]

For those of you who are experienced in this area, is there any way to predict which parent's phenotype (size, color) will become the dominant trait expressed in the hybrid offspring? Have y'all noticed any particular trends with your crosses?

[doublehelix]

Originally Posted by emzybo

For those of you who are experienced in this area, is there any way to predict which parent's phenotype (size, color) will become the dominant trait expressed in the hybrid offspring? Have y'all noticed any particular trends with your crosses?

The genetics of the tomato are pretty well documented. From what I am reading here it doesn't appear the author actually has any experience with plant breeding.

Check this link.
http://tgrc.ucdavis.edu/Data/Acc/Genes.aspx

It will give you all of the traits in tomato and the associated genetic informaton. Remember, dominant traits use UPPER CASE and recessive uses lower case.

For a more reliable source of info from someone that has actually created some tomato crosses please check this link. One of the better sources and he also posts here and at other message boards.

http://kdcomm.net/~tomato/gene/genes.html

You can PM me if you need further sources.