An experiment with bean crosses

[macmex]

In 2016 I had an accidental cross between Tennessee Cutshort and Cherokee Trail of Tears. I had already planted a good size patch of Tennessee Cutshort when a friend dropped by and gave me a number of Cherokee Trail of Tears plants, all nicely growing in a tray. I didn't have time to work up an area farther away, so I popped a couple into the ground about 15' from Tennessee Cutshort. Tennessee Cutshort has white flowers and fairly round brown seed. Cherokee Trail of Tears has black, elongated seed. Cherokee Trail of Tears is a good snap bean when the pods are young, but they get tough quickly, with age. It is super vigorous and a wonderful producer, not only of snaps, but also dry beans.


Tennessee Cutshort is very productive, not quite as vigorous and produces what is currently being called "full beans," aka tender podded beans. This means that it is an old fashioned string bean. It's pods remain tender for a very long time, compared to the tough podded varieties such as Cherokee Trail of Tears. One simply has to pull the string from the pod and it's tender, almost until the seed is ready to harvest drying and storage. Tennessee Cutshort produces white flowers and the seed is brown. I call the color of the seed "Kentucky Wonder Brown," as that is precisely the color. If you've ever grown Kentucky Wonder, then you know what I mean.



Come 2017 I planted over 100 plants of Tennessee Cutshort using seed from 2016.  By the time representatives of the Seed Savers Exchange arrived, in June, to interview us about seed saving these plants were in bloom. Standing in the midst of this planting I suddenly realized that something was going on. Three of the plants were producing violet colored flowers! Immediately I knew that we had a cross and I knew what it was! I let them go. I could have cut the vines off at the roots to preserve purity in Tennessee Cutshort, but I was intrigued. Both are very good beans. I had visions of selecting a black seeded version of Tennessee Cutshort. 

The cross (F1, first generation) produced slightly shorter pods than Tennessee Cutshort, which was interesting, as Cherokee Trail of Tears generally has longer pods than Tennessee Cutshort. These pods were usable for snaps, but not tender podded like Tennessee Cutshort. I could pull a string from them, but they were not as tender. Both the pods and seed were closer in shape to that of Tennessee Cuthort. This F1 generation had violet flowers.


 2018

I planted 10-15 plants of this seed from the F1 hybrid. The resulting plants would be F2 generation and should differentiate into various combinations of traits from the parent stock. I tried to grow just one plant per pole, but in order to ensure a plant per pole I did plant 2-3 seeds per pole and then... couldn't bring myself to cull the extras. About half the poles had one plant and the other half had 2-3 plants. In the future I will be ruthless in culling, as it is important to know what you've got on a given pole and not get mixed up between plants.

Remember, the seed I planted was uniformly black and round. Well, as soon as I had flowers I knew we had differentiation going on. We had both violet and white flowers. As the season progressed I noted that we had a good number of variations in pod shape and quality. About half of the plants produced round pods, much like Cherokee Trail of Tears, though they were shorter than either of the parent stocks' pods. These pods were TOUGH and some had black seed. Others had brown seed.  I wouldn't even try to use them for snaps. Many had true cutshort seed, meaning the seed was crammed into the pods so tightly, that it dried down with squared ends. All of the plants which produced really tough (unusable for snaps) pods, whether brown or black seeded, had seed which was smaller than either that of Tennessee Cutshort or Cherokee Trail of Tears: interesting!

Neither Cherokee Trail of Tears nor Tennessee Cutshort are true cutshorts. This observation confirmed to me what I had been told years ago, that Tennessee Cutshort probably hailed from a small area in Tennessee and Kentucky where they call non cutshorts by the name because they are derived from true cutshorts and are similar in appearance.


The good points of this particular F2 variation are 1) high productivity, 2) it would make an excellent dry bean and 3) the seed is beautiful. But forget about using it as a snap.

We had other variations in seed color pod shape and quality. One of the primary variations, which I liked was a flat podded, brown seeded, white flowered F2. Though I was hoping for the fatter pod of Tennessee Cutshort, rounded seed and black seed coat; this one really caught my eye. It's was very nice. Here's what the pods looked like at eating size.


Here's what they looked like when dry:


The seed looked almost the same as Tennessee Cutshort's, though I believe it's just a little more slim in shape.

I also had a plant which was nearly the same, but whose pods were markedly knobby. They were, however, of excellent full bean quality. I saved seed of both of these.

Before frost I went through and harvested seed of most of these, especially those I wanted for possible future grow outs.

November 23, 2018

I was out in the garden and noticed that one of those poles had a clump of vine, near the bottom with quite a few pods. It looked like the vines had slid down the pole and I had missed them. Many were dry. So I grabbed a coffee can and started picking pods. Then, that evening when I had a call from my son, I sat and shelled those pods while we spoke. Most seed was of the round podded, black seeded kind. But some were obviously of a tender, flat podded, black seeded bean!
 

Next year I plan on growing out some plants from this seed as well as a few of the flat, tender podded, brown seeded ones. 

I anticipate that it will take four to five more years before I have anything really stable. I've never done this before. In the past I've discarded crosses, seeing that they were inferior to their parents. But this cross grabbed my attention and, I'd like to do this at least once in my life.

[macmex]

Here's a picture of the kind of mixture I got from the F2 seed. This is now F3 seed.

[macmex]

Here are three pictures of the tough podded (only good for dry beans), black cutshort variation which arose in the F2 generation. I probably won't plant these, but it would be interesting to see if any tender podded offspring might come out of a planting of these. I'll probably freeze a bit of this seed, just in case.

This picture shows the round pod characteristic.


This picture shows how crammed the seeds get in the pod.


This photo shows just how square ended some of these seeds are:



It's interesting to me that this F3 seed is noticeably smaller in size than either of the parent varieties.

[philagardener]

Nifty - it really is neat to see all the things that can come out of a cross like this!

[macmex]

Seems like the sky's the limit for selection. The main limiting factors are:

1) Space
2) Time
3) Ability to keep notes

I'm going to have to limit myself to growing one or two variants, or it'll get out of control.

[macmex]

Well, I only got around to planting the black seeded variant this year. I put out 12 poles, most with 2 plants per pole. The earliest pods and seed which formed were on plants which produced pods which looked like they were going to be tender, but which toughened up rapidly when maturing. I discarded seed from these.

Four poles had plants which were a bit later and produced really nice, large, plump pods which remained tender until the seed was drying. The seed was black and chunky. In fact, I believe these pods remained tender even longer than Tennessee Cutshort itself!



I don't know what this pod shape is called, but I really like it. It's very easy to work with, in preparation for the pot. When reaching full maturity the pods often puff out a bit, leaving air space around the seed, yet they are still quite tender. The seed is black. Not a single plant, planted from this black seed, produced anything but black seeded offspring.



This selection appears to be prolific. I really look forward to growing from it in 2020. Also, if I can find the time and space, I will yet plant from the brown seeded selection (2018 seed). It had the same exact style of pods.



Though it'll probably be a couple more years before I can definitely say I have a stable new variety, I'm already day dreaming about a name for it!

[rdback]

Great story George. Keep after it, I like where this is going!

[macmex]

Friday, November 1, I managed to get out into the garden after nearly 20 days absence (been doing firewood and other things). Among other things, I browsed through the patch of my F3 bean crosses, especially the tender podded ones. I found only a couple of dried pods with seed, but here's a photo of them. You can see the different shape they have from the round podded ones which matured tough.

[glen]

I missed this thread. Good work George!!

[macmex]

I'm enjoying this experiment, and even more so, as it appears that I may actually be going to able to produce a superior (not just different) variety. It takes much time and space to do this, but it's not hard.

[glen]

Plant breeding is hard work. It takes patience. And, its a thankless job. Keep it up.

[macmex]

It's 2020 and I planted a 16' row of the F4 black seeded selection. I mainly planted from select seed which I chose from plants with the most tender of pods and larger seed. This year every plant has bloomed with violet colored blooms, which almost certainly means that all will produce black seed. Here are some photos of the first pods to form. They certainly look like they will be tender podded. I like the length on some, which is longer than Tennessee Cutshort.

[macmex]

Well, my F4 generation cross seed has performed very well in the summer heat, though this summer hasn't been the hottest, it's certainly been challenging. The cattle panel of this bean has remained healthy throughout the heat and is now setting pods again. I want to reiterate, if one wants to select from a cross, keep individual plants apart, so you can tell what's what. 

The closer I look, the more variation I see in the pods, this season. There are creaseback and flattened. There are even some which are more round in shape. What I primarily want is a tender podded string bean which, when strung, keeps its tenderness for a long time. I'm also intrigued with getting the black colored seed and violet flowers of Cherokee Trail of Tears.

Here's a photo of what we ate the other night, from this planting. There are some in there, still, which get tougher than I want. If I serve a mess of these alongside a mess of Tennessee Cutshort I get complaints. Still, I think we can select until we have that same quality. If you look closely at this image, you'll see that there are variations in pod characteristics.

[macmex]

Last fall, just before the weather got really wet, I was out in the garden and once again, I gleaned seed from this cross. Life has been so busy that all I managed was to dry the seed, in the pods, and toss them into the freezer, to kill weevil eggs. About a month ago I took them out, meaning to sort the pods and... here we are. It's almost time to plant again!



I found three main variations in the pods. They're visible in this photo. I found a couple pods which were significantly longer and straighter than the rest. They were also darker, once fully dried. You can observe these toward the top of the photo. I suspect these are the culprits which come up tough in a batch of maturing green beans.

Next, there are a fair number of pods with the fattened tips and flat pod style. I've noticed these from the growout of F2 seed. These make very attractive, tender snaps. I've observed this pod shape when growing Childers Cutshort (something I need to do again). The weakest point of this pod style is that the seed is small. I prefer a plumper seed, but otherwise, this is an excellent bean.

Finally there were a fair number of dried pods which would easily pass for Tennessee Cutshort. They're more of a creaseback and the pods are fat, though shrunken. I should probably focus on these in light of my original stated goal.

After sorting, about half of the remaining pods were what I'd call "transitional." They're kind of in between two of each of these three styles. Though all the vines appeared to be identical and all the seed is black and roughly of the same shape, there is still a LOT of variation in this seed stock.  

[macmex]

Well, this has probably been the most challenging garden year of my life, and that, mainly on account of my own health and disrupted routine. Still, I did get some of this experimental bean planted this year. I chose seed from pods which most resembled Tennessee Cutshort, but which had black seed. I did my initial planting on June 12, and then started more seed, to fill in gaps, on June 28. August 19 I planted three more poles (3 plants) of the same seed.

Planting so late meant that these beans have been ready to put on pods for a while, and yes, they have put on a few pods, sporadically, but the heat has kept them from producing up until now. I noticed flowers on August 8, but hardly any pods until this week. Here's a photo of two pods I found, yesterday evening.




They look just like Tennessee Cutshort, right down to the irregular shape. I notice this irregular shape thing, in that I'll look at some pods and think, "Aren't they beautiful!" But when I take a picture of them I think, "Couldn't I find some more evenly shaped to photograph?" Well, I need a lot more pods to chose from in order to do that. This is exactly how it goes with Tennessee Cutshort. Despite the irregular shaped pods, it's a super high quality bean. I hope, perhaps this year, to achieve uniformly tender, string beans with this selection. Hopefully with two more growing seasons I will be able to name and release a new variety of pole bean.

Sure takes time!