Open Source Plant Breeding Forum

General Category => Nightshades => Plant Breeding => Tomatoes => Topic started by: Steph S on 2021-07-10, 05:21:34 PM

Title: videos and tips for crossing technique
Post by: Steph S on 2021-07-10, 05:21:34 PM
Just thought I would start a thread here for anyone to post their favorite videos or tips on the hand crossing technique, for anyone who is starting out and making their first crosses.
There are dozens of videos that show the process of choosing a flower to emasculate, and quite a few different ways of doing it.   This video is I think my personal favorite, closest to the way I do it myself, except that I use my fingernails instead of tweezers to clip the sepals and petals, then remove a strip of the anther cone first so the rest of it can be pulled away from the exposed stigma.
https://www.youtube.com/watch?v=rPOXEDS9yIo (https://www.youtube.com/watch?v=rPOXEDS9yIo)

I've tried using tweezers but it seemed like I was inflicting more trauma on the bud than when I just use my handy sharp nails.  There are some different and very cool techniques out there in the videos, more dexterous than I will likely try to be (but I can admire it!).

Something I learned from experienced breeders is that the stigma is usually not fully mature on the day you emasculate the flower.  So although I apply pollen immediately, I also repeat that for two more days.  When the stigma is mature and receptive it forms more of a knob on the end and becomes sticky, and you can see that it clears a line as you drag it through the pollen.  Then you know you got it pollinated when it was ready.

Another tip which iirc came from Tom Wagner, is to collect pollen from several donor flowers.  This way you have pollen at different stages of maturity in the mix, and increases the chance of getting the right stuff to your mature stigma.  Personally I use one container for each variety pollen, and continue to collect fresh into that for my three day process, from multiple donor flowers on the plant.    I have some small containers with shallow lids, so I turn them upsidedown, use the lid to collect and dispense pollen (which is shallow enough to dip your stigma into), and use the container bottom as the 'lid' to keep it closed in the cool basement where it waits for next day action.

Please share your favorite resources and tips, and tell us your personal favorite techniques.

Title: Re: videos and tips for crossing technique
Post by: William S. on 2021-07-10, 06:42:39 PM
When I did my two mission mtn sunrise x big hill earlier I used fresh big hill pollen each day for three days and I emasculated younger flowers. Then I clipped all competing flowers with my fingernails. I don't think I used tools because of relatively sturdy flowers. I may have, just can't recall. Still waiting to pick those two fruits but I am pretty sure I nailed it.

I have needed my botanical forceps for slender stigma emasculations. If I were doing a lot I would use tools. Though I have been using botanical forceps almost my entire adult life to dissect plants.

I find that my flowers dry up when emasculated outside. Especially now when it is maximally hot, dry, and sometimes windy.

So what I do instead is utilize exserted mothers but when I really want a cross that way I transfer pollen still manually. It works great if the mother is potato leaved and father regular leaf as F1's will be regular leaf. Which is why I've selected Mission Mountain Sunrise for potato leaf like the unknown Lofthouse landrace that was it's own cross mother. It's also why I've crossed MMS to BH because BH has better exsertion. MMS is inserted to modestly exserted. I'm setting myself (and others hopefully) up for easier future crosses.

Other traits that help ID crosses in F1: red is dominant over yellow. Non-rugose over rugose. Stripes on fruit are recessive. 

Sometimes you can see the pollen especially through a hand lens or macro lens on a camera before and after absent then adhered.

I think doing a few crosses than growing lots of F2s might be more important to achieving trait combination goals than lots of crosses than growing out few of each line.
Title: Re: videos and tips for crossing technique
Post by: galina on 2021-07-15, 06:57:28 AM
For making pea crosses: 

https://www.youtube.com/watch?v=Pq7-JGRmFBc
Title: Re: videos and tips for crossing technique
Post by: Steph S on 2021-07-15, 08:00:38 AM
That's really a superb video Galina!  Thanks.  :)
Title: Re: videos and tips for crossing technique
Post by: Garrett Schantz on 2021-07-15, 05:45:17 PM
I like this video for tomatoes - some other things.

https://www.youtube.com/watch?v=C1Riedng9WY&t=


This one is nice for peas.

https://www.youtube.com/watch?v=zMEnXXzmV3s&t=


There are a lot of nice videos on YouTube.
Title: Re: videos and tips for crossing technique
Post by: Adrian on 2021-07-16, 05:53:32 AM
Thank you for your video! I will try to hybrided a tomato.
I have think at yellow pear x san marzano 2
Title: Re: videos and tips for crossing technique
Post by: Adrian on 2021-07-21, 01:50:14 PM
This link is in french but he has a lot of pictures extremly interested.
https://jardinierparesseux.com/2018/07/15/comment-creer-votre-propre-tomate-hybride/
Title: Re: videos and tips for crossing technique
Post by: Diane Whitehead on 2021-07-25, 09:39:30 AM
I am growing ten dwarf varieties which I plan to cross with twelve varieties of multifloras.

I emasculated some dwarf flowers and went to collect pollen from the multifloras. I held a black plastic yogurt lid under open flowers which I tapped. No pollen. I did this to dozens of flowers. None. They must have produced some because their earlier flowers have developed fruit.

I finally did get pollen from a plant from the Q-series Panamorous grex from the Experimental Farm Network. I don't want to use it, though, as I have no idea yet what it is going to be like.

Why did none of my named multifloras drop me some pollen? Conditions seem right.  It is sunny, 21 C (about 70 F), just before noon.
Title: Re: videos and tips for crossing technique
Post by: Adrian on 2021-07-25, 09:45:37 AM
I have note the same problem and it that why i have glide the anther cone on the stylet and i have shake the flower! The anther must well contain pollen! I have not searched to collected pollen.
29C yesterday.

I have sometime see a cloud exit of the flower.
Title: Re: videos and tips for crossing technique
Post by: William S. on 2021-07-25, 09:54:30 AM
I have trouble getting useful amounts of pollen from a number of things. Sweet Cherriette is one such culprit. Judging by yesterday Solanum galapagense is another. I'm spoiled by habrochaites though. Maybe I'll just make habrochaites the pollen parent for all crosses!
Title: Re: videos and tips for crossing technique
Post by: Steph S on 2021-07-25, 10:54:38 AM
Time of day, humidity, and maturity of the flower are three factors I've encountered for getting pollen.  My best window is usually between 11 am and 3 pm.   But if the humidity is high,  maybe not.  If I don't get it at 11, I'll try again throughout the primo hours until I do - but some days I'm getting nothing, maybe because of humidity. 
And then there's flower maturity.  Flower might be open and looking ready to shed, but it's not.  The day after, the same flower will give generously.
Just being persistent is the only advice I have to offer, and try as many flowers as you can.
Title: Re: videos and tips for crossing technique
Post by: William S. on 2021-07-25, 11:03:18 AM
Wow the pollen availability is not great today! Hopefully the Bombus are doing a good job of mixing things up. They are hitting all the LA2329 Habrochaites flowers and that knocks them out of production. Only found one and one galapagense. Re daubed a couple stigmas but nothing more to do.
Title: Re: videos and tips for crossing technique
Post by: Steph S on 2021-07-25, 11:41:46 AM
I just went out and tried for pollen from some densely clustered cherry tom flowers - I found it was difficult to get the tapping right so pollen would come out.  I had to angle the receiving surface instead of holding it flat,  and instead of tapping the back of individual flower, tapping higher up where there's a bend in the flower stem.  That seemed to give me more control of where the anther cone was going.   I only get pollen when I can actually hear the anther cone hitting against the surface, then it spits out.   I sometimes have wondered if this would harm the stigma but it never seems to do that, afaik it just seems to guarantee that it is well pollinated and sets a fruit.
Hope that helps, Diane.
Title: Re: videos and tips for crossing technique
Post by: Diane Whitehead on 2021-07-25, 12:18:52 PM
Thanks, Steph, William and Adrian.

I will keep trying.

Today I watched the bumblebees on Red and Orange Centiflors.  They checked out each flower but only entered a few.
Title: Re: videos and tips for crossing technique
Post by: Steph S on 2021-07-25, 01:52:01 PM
There's another good point Diane. 
One of the plants I was using for pollen donor this year had scanty flowers, and so I really noticed when a flower gave me a generous amount.  I went back to the same one next day before repeating the cross.  It still looked freshly open.  Couldn't get a drop from it.
Obviously it would be the same with bumblebees, that once they have plundered the pollen there is no more to be gradually released, even if the flower looks like it's not done.
So very possibly the bumblebees have already taken what you hoped to obtain.
I've watched them on my plants as well, and they are very thorough, never miss what's freshly opened nor ever visit the same one twice.
Title: Re: videos and tips for crossing technique
Post by: Roland on 2021-07-25, 02:12:55 PM
A vibrating electric toothbrush can help to collect pollen. Sometimes i do not get pollen but with the use of the vibrating electric toothbrush i will.

Also i have some plants that are very difficult to get good amound of pollen :(

Title: Re: videos and tips for crossing technique
Post by: Diane Whitehead on 2021-07-25, 03:18:30 PM
I've got to keep flowers away from the bumblebees.  I guess I will cut bouquets and bring them in the house.

I now have stems of 7 kinds of almost-ready flower clusters in small jars of water, each placed on a black plastic lid so I'll be able to see whether any pollen drops.
Title: Re: videos and tips for crossing technique
Post by: Roland on 2021-07-29, 03:13:29 PM
Yarn in different colors is ideal for marking the young flowers for your cross pollination