Genetics of Tomato Rootstock Breeding: genetic distance, heritability, vigor, resistance

and selection strategy

Sean Fenstemaker, Nancy Huarachi Morejon, Mohammed Masud, Matt Kleinhenz, Stephanie Wedryk and David Francis

The Ohio State UniversityFrank Louws

NC State University

Mohammed MasudNancy Huarachi Morejon

1. Evaluate the role of rootstock (RS) in increasing scion vigor

2. Test the hypothesis that genetic distance (GD) between parents of a hybrid RS would predict vigor, greater GD will translate into greater vigor

3. Inbred parental lines as female parents (S. lycopersicum), and accessions of wild species as male parents (S. arcanum, S. chilense, S. corneliomulleri, S. habrochaites, S. pennellii, S. peruvianum, and S. pimpinellifolium)

Goals of Mohammed’s work

Rootstock hybrid seed production

Most commercial tomato rootstocks are hybrids derived from wide-crossesCommon issues with wide-crosses include:

seed yielduniform germination“compatibility”

Matrix of Genetic Distances: Can we predict performance?

1 2 3 4 5 6 7 8 9 10 11

Average = 0 0.6991 0.4331 0.4576 0.4826 0.522 1.731 1.6864 2.0365 1.2162 2.5706

Stdev = 0 0.0432 0.0381 0.033 0.0286 0.0229 0.2559 0.2475 0.3141 0.1569 0.4137

Average = 0 0.5494 0.624 0.5625 0.5678 2.2393 1.6495 2.4922 1.2645 2.2282

Stdev = 0 0.0217 0.0288 0.0218 0.0224 0.3524 0.2404 0.4 0.1665 0.35

Average = 0 0.1634 0.2413 0.3308 2.0374 1.5396 2.2282 1.5916 2.0595

Stdev = 0 0.1122 0.0889 0.064 0.3143 0.2186 0.3501 0.2339 0.3183

Average = 0 0.3866 0.4239 2.0251 1.5276 2.2167 1.856 1.8697

Stdev = 0 0.0494 0.0403 0.3122 0.2163 0.348 0.283 0.2825

Average = 0 0.3069 2.2645 1.6796 2.0268 1.2162 2.2888

Stdev = 0 0.0705 0.3566 0.246 0.3123 0.1569 0.3611

FG01-5013 Average = 0 2.0128 1.7836 1.8171 1.5614 2.0349

Stdev = 0 0.3099 0.2664 0.2727 0.2263 0.314

Average = 0 1.2257 1.1706 2.9456 1.1113

Stdev = 0 0.1547 0.143 0.4873 0.1341

Average = 0 0.542 2.4608 0.7062

Stdev = 0 0.0221 0.3936 0.0413

Average = 0 2.0251 0.5511

Stdev = 0 0.312 0.0221

Average = 0 2.0496

Stdev = 0 0.3164

Average = 0

Stdev = 0

*Each cell represents a hybrids genetic distance

Multi-location Field Trials

Close up of root stock selection showing the training system, cleft graft and high

quality of transplant color and growth; 7 days after transplanting, Willow Springs, NC.

Hilltop Farms, Willow Springs NC

Wooster, OH

Wooster OH

Wooster OH

1) GD is positively correlated with scion growth.

2) GD is negatively correlated with seed size and %

germination.

P= 0.023; r2 = 0.24

Results:

SGH07-313, SGH07-314, SGH07-316, SGH07-319, and

SGH07-320 were top performers.

Rootstock MN NC OH MN rank NC rank OH rank Comment

SGH07-303 30.04 99.97 32.11 2 8 2 poor germ

SGH07-319 28.06 110.85 27.32 3 3 6

SGH07-316 25.40 119.21 28.32 7 1 5 poor % graft

SGH07-305 25.28 108.46 29.09 8 6 4 poor germ

SGH07-315 33.80 97.09 24.73 1 11 8

BEAUFORT 20.90 110.17 25.94 13 4 7

SGH07-320 22.40 96.03 31.05 10 12 3

SGH07-326 16.20 102.51 34.89 17 7 1 poor % graft

SGH07-313 25.59 98.40 23.84 6 10 11

UNGRFTCELEB 23.50 109.62 21.04 9 5 13

SGH07-336 15.64 111.75 23.41 18 2 12 OH x FL

MAXIFORT 19.55 99.78 24.09 14 9 10 high suckers

SGH07-314 25.77 94.13 19.89 5 14 16 sml seed, high suckers

SGH07-323 26.69 90.99 17.19 4 17 17

SGH07-327 18.26 95.24 24.59 16 13 9

SELFGRFTCELEB 21.63 91.97 20.66 12 15 14

SGH07-333 22.19 91.54 13.77 11 16 18

SGH07-332 18.82 90.70 20.52 15 18 15

Genetic distance does predict scion vigor (though not yield), seed size and seed germination.

Take Home

High Tunnel trial w/ scion ‘Cherokee Purple’

OH-314 un-grafted

• Grafting does not always significantly improve field performance (in the open field). *Exceptions

–When soil-born disease may limit production–When scion is an heirloom or otherwise weak–When season extension techniques are used

Conclusions

Can genetic selection improve rootstock seed quality?

Crosses

Germination

Grafting

Field evaluation

Nancy’s goal: Identify selection points in rootstock breeding

Female and male parents for hybrid seed production

Tuesday, June 05, 2018Can genetic selection improve rootstock

seed quality?20

Experimental design

Randomized Complete Block Design with 40 crosses

10 female plants

4 male plants

2 experiments (Winter-spring; Summer-Autumn)

2 blocks/experiment

Can genetic selection improve rootstock seed quality?

21

Results

Tuesday, June 05, 2018Can genetic selection improve rootstock

seed quality?22

Genetic, Environment, Interaction

Results

Tuesday, June 05, 2018Can genetic selection improve rootstock

seed quality?23

P = 0.018

R2 = 0.24 Selection

Results

Crosses

Germination

Grafting

Field evaluation

Selection points in rootstock breeding

Fruit set, seed number and quality

% SuccessIncompatibility

Selection point traits are heritable and positive variation exists

Percentage and rate

Performance

Take Home

• Selection points include fruit set, seed number, seed size, seed germination, grafting success, and performance when grafted.

Acknowledgements

• OREI

• SCRI

• Partners: Frank Louws and Matt Kleinhenz