Husker Wheat Breeding Program
Fran tenBensel Benne
Author
08/04/2020
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72
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Professor P. Stephen Baenziger talks about the University of Nebraska–Lincoln wheat breeding program at Havelock Farm in Lincoln. He highlights the hybrid wheat yield trial and hybrid crossing blocks. This is where new hybrids for testing are produced.
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- [00:00:00.000](upbeat music)
- [00:00:10.290]Hi.
- [00:00:11.123]We're in a hybrid wheat yield trial.
- [00:00:13.980]Every one of these plots
- [00:00:16.280]is either the parent of the hybrid or the hybrid itself.
- [00:00:20.220]The hybrid was made with a chemical hybridizing agent.
- [00:00:24.000]To me this is where the magic begins.
- [00:00:26.970]This is a hybrid crossing block, not a yield trial,
- [00:00:31.180]but a crossing block
- [00:00:32.940]where we're making new hybrids
- [00:00:35.150]for the next year's yield trials.
- [00:00:38.860]What we have is a male, then a female,
- [00:00:42.260]and then another male.
- [00:00:44.290]Now in this crossing block,
- [00:00:46.670]the male is the same up until you see
- [00:00:49.640]the very tall plants,
- [00:00:51.870]which are are the triticales,
- [00:00:52.907]and that marks the end of this set of crosses.
- [00:00:56.490]But each female is different,
- [00:01:00.390]and what I really like is because we timed these properly
- [00:01:05.290]and the chemical worked properly,
- [00:01:06.820]if you look at this, each one of the females
- [00:01:11.560]is gaping and has that real yellow-green cast to it.
- [00:01:16.750]They're ready to receive pollen.
- [00:01:18.990]The male is pollinating,
- [00:01:20.670]so hopefully we're gonna get hybrid seed,
- [00:01:23.120]fairly good yields.
- [00:01:24.810]And that's what we have here.
- [00:01:27.150]So this is where we make our new hybrids for testing.
- [00:01:30.590]And this is what make the chemical hybridizing agent
- [00:01:33.250]so critical for us,
- [00:01:35.060]is we can sterilize virtually any female line
- [00:01:39.280]so that we can make a hybrid with it.
- [00:01:41.430]And then if we see a hybrid we want,
- [00:01:44.030]we can convert it to a cytoplasmic male sterile
- [00:01:47.110]or we could try to make it with CHA,
- [00:01:50.170]something like that.
- [00:01:51.660]And if you pan across,
- [00:01:54.860]you will see we have a whole series
- [00:01:56.950]of these crossing blocks separated
- [00:02:00.260]so that there are, we're gonna make about,
- [00:02:03.280]I think, 360 new hybrids this year.
- [00:02:08.260]And these are all basically ones
- [00:02:10.360]we would predict from our best estimate
- [00:02:13.070]of last year's yields and the previous year's yields
- [00:02:16.200]and the genomics that we have to understand the lines.
- [00:02:20.400]So this is the hybrid crossing block
- [00:02:23.350]using a chemical hybridizing agent,
- [00:02:26.300]and it's worked so far, we think, really well.
- [00:02:29.140]We'll see what the yield looks like
- [00:02:30.610]at the end of the season, but so far,
- [00:02:32.890]everything's looking really, really nicely.
- [00:02:35.118](upbeat music)
- [00:02:36.830]So what we have here is to give you an idea
- [00:02:40.110]of how the chemical hybridizing agent works
- [00:02:42.760]and how critical it is to put it on at the exact right time.
- [00:02:47.010]Here is a male fertile line that is unsprayed,
- [00:02:51.650]and you can see the anthers extruding,
- [00:02:53.470]and it looks very much like normal wheat.
- [00:02:57.370]The next plot over, now this plot is a plot
- [00:03:01.990]that was sprayed with the chemical hybridizing agent
- [00:03:04.610]at the right time.
- [00:03:06.510]You can see that it's a little bit stunted.
- [00:03:09.060]That's normal.
- [00:03:10.410]You can also see that the heads
- [00:03:13.290]look very wide open.
- [00:03:15.820]That's called gaping.
- [00:03:17.740]What happens is when you male sterilize the line,
- [00:03:21.780]the female discovers it's not being fertilized
- [00:03:25.010]and opens the glumes to receive pollen.
- [00:03:28.760]So to see a whole strip of plants
- [00:03:33.470]completely sterilized by the chemical hybridizing agent
- [00:03:37.730]is a really nice sight to see
- [00:03:39.980]for someone working on hybrid wheat.
- [00:03:43.060]So that's what we're looking at here,
- [00:03:44.900]is females that are receptive
- [00:03:48.340]to get new pollen to make hybrids.
- [00:03:51.030]The male has been sterilized so it will not self,
- [00:03:53.830]which is what wheat would normally do.
- [00:03:56.670]And we can do it on a scale
- [00:03:58.950]which we've never seen before in Nebraska.
- [00:04:01.505](upbeat music)
- [00:04:02.770]Now this is the exact same variety
- [00:04:05.820]as the first two that we've shown you,
- [00:04:08.090]but this is one where we sprayed
- [00:04:09.377]the gametocide on too early.
- [00:04:12.510]We deliberately did this because we wanted to get an idea
- [00:04:17.210]of how the gametocide works,
- [00:04:19.900]what's its window of application is.
- [00:04:22.500]And you can see that if you spray it on too early
- [00:04:25.910]at the same dose you do on a larger plant,
- [00:04:29.120]you can get a lot of phytotoxicity.
- [00:04:32.600]The plants are probably sterile
- [00:04:34.100]but they may also be female, sterile, or barren.
- [00:04:37.280]There's a lot of difficulties with that.
- [00:04:39.640]It just shows you the care that you need to use
- [00:04:42.200]this chemistry with, but again, it's a phenomenal chemistry
- [00:04:45.760]in that we can make hybrids to test,
- [00:04:48.340]which we just showed in the hybrid testing trials.
- [00:04:51.510]And this is the easiest way to make them.
- [00:04:54.700]What we have here are CMS lines
- [00:04:58.240]that are sprayed with the CHA from this direction down.
- [00:05:03.090]From this direction that way, it's the CMS lines unsprayed.
- [00:05:08.370]And what we're curious about is to see
- [00:05:11.440]how the yield differs between CMS lines that are sprayed,
- [00:05:16.670]CMS lines that are unsprayed,
- [00:05:19.760]with the idea that the difference should be due
- [00:05:23.050]to any phytotoxicity with the chemical.
- [00:05:26.180]Now looking at the CMS lines we can see
- [00:05:28.520]that we did bring in a few fertiles when we combined,
- [00:05:31.910]which will be sterile in here, fertile in there.
- [00:05:34.890]So it will be not a quite a perfect comparison,
- [00:05:38.410]but it's a reasonable comparison to make.
- [00:05:41.400]So we're gonna try to get an idea
- [00:05:43.190]of how much does the CHA hurt our lines
- [00:05:47.190]and how much can we do when with the CMS type of program?
- [00:05:51.920]So what we have here
- [00:05:54.030]is a CMS female
- [00:05:58.070]that has been sprayed with the CHA.
- [00:06:00.810]The idea being if it's sterile already,
- [00:06:04.300]then the reduction in seeds set
- [00:06:06.840]will be due to the spraying of the CHA,
- [00:06:09.930]because it is slightly phytotoxic.
- [00:06:11.800]You can see it's a little bit shorter.
- [00:06:13.510]We have a common male on both sides.
- [00:06:16.360]If you turn around
- [00:06:18.900]you will see what the CMS looks like unsprayed,
- [00:06:23.010]and that unsprayed plot
- [00:06:24.800]unfortunately has a few fertiles into it,
- [00:06:27.410]so it's not quite a direct comparison.
- [00:06:30.190]But it's a reasonable comparison to see
- [00:06:32.380]what CMS sterility with pollination to make hybrids
- [00:06:37.940]compares to CMS that has been sprayed with CHA
- [00:06:41.520]so the main effect is the effect of the CHA
- [00:06:44.480]on how much seed yield you get.
- [00:06:46.320](upbeat music)
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