Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and...
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Transcript of Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and...
![Page 1: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/1.jpg)
Use of the Roundup ReadyTM Trait to Estimate Selfing in Hand Crosses
of Alfalfa
Mark McCaslin and Stephen Temple
Forage Genetics International
![Page 2: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/2.jpg)
Background• Alfalfa is predominately cross pollinated• % selfing is difficult to determine without
simple and effective genetic markers• Transgenic traits offer unique advantages in
studying alfalfa genetics and reproductive biology.– Cross vs self pollination– Pollen flow studies
![Page 3: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/3.jpg)
Advantages of the Roundup Ready Trait
• CP4 gene inherited as a single gene dominant trait• Easily identified phenotype
– Efficient high-throughput screening• Multiple transgenic events available with event-
specific PCR primers.
Promoter CP4 Gene TP Terminator
Event specific PCR
![Page 4: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/4.jpg)
Experimental Design
• Two populations of plants (~50 plants each)– Pop B – simplex plants containing transgenic
event B (Bxxx).– Pop D – simplex plants containing transgenic
event D (Dxxx).
• Non-emasculated hand crosses were made in greenhouse Pop D (female parent) x Pop B
![Page 5: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/5.jpg)
Experimental Design
• Seed harvested from Pop D plants• Progeny were sprayed with Roundup• RR progeny were tested with event-
specific PCR to identify the RR genotype– BD dihomogenic – D event only– B event only
![Page 6: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/6.jpg)
Results• 74.4% of the progeny were tolerant to Roundup
(75% expected).• Genotypes of the RR progeny were established
with event-specific PCR and frequency of each genotype was compared to theoretical value.
Genotype # plants % actual % expected
BD dihomo 2068 30.5 33.3
B only 1923 28.4 33.3
D only 2776 40.9 33.3
![Page 7: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/7.jpg)
Discussion• Increased frequency of D event only
progeny and decreased frequency of B event only and BD dihomogenic is likely due to unintentional selfing during hand crossing.
• Data suggests ~10% selfing in this cross• Similar results from other crosses over
multiple years, locations and genetic backgrounds.
![Page 8: Use of the Roundup Ready TM Trait to Estimate Selfing in Hand Crosses of Alfalfa Mark McCaslin and Stephen Temple Forage Genetics International.](https://reader036.fdocuments.in/reader036/viewer/2022082710/56649dc05503460f94ab48a0/html5/thumbnails/8.jpg)
Discussion
• Other pollination related experiments planned or in process:– Cross vs self-fertility with leafcutter bees in
commercial seed production setting.– Pollen flow studies with honeybees