AOSA/SCST Region IV - Southwest Referee

2013

Phaseolus vulgaris - Organic Media Comparative Germination Testing

Presented by David M. Johnston, RSTMonsanto Veg. Seed Phys. Lab

Photo Credit: Michigan Dept. of Agriculture 1954

Background InformationPrior to 1997, crops designated in the AOSA Rules to be tested using “S” as a substrate could be tested in either sand or soil. These germination test results could be used for the purpose of labeling. In 1997, an AOSA Rules proposal was adopted to remove soil as a “primary testing substrate” for germination testing. The wording for the AOSA Rules change was as follows……………..

“Since it is generally difficult to obtain consistent supplies of soil, it is not to be used as a primary testing substrate. However it may be necessary to use it when seedlings show phototoxic symptoms or if evaluation of seedlings is in doubt.”

Soil is still commonly used as a substrate by some labs for comparative testing, investigative purposes and vigor testing with good success.

Current Status of “Organic Media”• Federal Seed Act (Sec. 201.56b) permits germination retesting to be

performed with sand or “soil”. The FSA states that “soil” is understood to be “potting soil”…

• Canadian M&P (4.5.2c Soil-less mix) states “samples may be retested in a soil-less mix to confirm tests made by other methods, for example testing samples which produced seedlings showing symptoms of phytotoxicity when germinated on paper or in sand. The soil-less mix should be a good quality, organic soil-less potting mix….”

• ISTA Rules define “organic growing media” as a mixture of organic fibers (such as peat, coconut, or wood fibers, with size at least 5 mm) and mineral particles (such as sand, perlite, and vermiculite; comprising 20% by volume). Organic growing media can be used for initial germination testing of sunflowers and faba beans. It is also permitted for comparative testing and retesting of other species.

• AOSA Rules permit testing pelleted onions that have been treated with a specific seed treatments using organic growing media composed of fine (#3) vermiculite, dry fine peat moss and water at a 1:1:4 ratio by weight. The organic media and seed are placed on an RT and tested. (aka Cornell Test)

•Purpose of this referee was to compare Bean (Phaseolus vulgaris) germination testing using paper (i.e. towel/Kimpac), sand and organic media (composed of approximately 50% mineral and 50% organic media).

•There was a bit of variation in the paper media used and the organic media composition (i.e. AOSA 50/50 mix, comm. organic media) used among labs, as well as the testing equipment (i.e. chambers, greenhouses) used to conduct the test.

•This referee was not intended to be a formal scientific study but more of a “casual” organic encounter and sort of a “first date” for labs to try using organic media for germination testing.

Referee Purpose and Design

No. Seeds Tested Media Temp. Light Test Duration

400 per seed lot(2 seed lots used)

PaperSand

Organic media

25C or

20-30C

8 hr. min. 8 days

AOSA/SCST Participants• Calif. Crop Improv. UC Davis Mary Voorhees • Harris Moran Olga Maseda • Incotec Ha Ung • Kent Agri Lab Dianne Gilhuly • Mich. Crop Improv. Randy Judd • New York State Seed Lab Michael Loos and Team• SCST Associate Member Phyllis Dawson • Sorghum Partners Terezo Luera • Eurofins STA Connie Obrien • Syngenta Rebekah Wagner • USDA Seed Lab Pattsy Jackson • Utah State Seed Lab Stan Akagi• Monsanto Veg. Seed Lab Oxnard Seed Phys. Lab

Team

Paper- Towel/Kimpac Combo

Sand & Organic Media - Chamber

Organic MediaSand

Sand & Organic Media - ChamberOrganic Media

Sand

Organic Media – Greenhouse – Sample 1

Organic Media – Greenhouse – Sample 2

Sample 1 – Statistical Summary

Non-matching letters above graph columns indicate a significant statistical difference.

Ok

Sample 2 – Statistical Summary

Non-matching letters above graph columns indicate significant statistical difference.

Ok

Sample 1 & 2 – Normal Seedlings

Sample 1 was a low quality seed lot and sample 2 was an average quality seed lot.

Possible Next Steps• This “Proof of Concept” study indicates

organic media is a suitable substrate for Phaseoulus vulgaris germination testing.

• Conduct a formally designed experiment regarding the use of organic media for germination testing of Phaseoulus vulgaris.

• Add the definition of “organic media” to the AOSA Rules.

•AOSA/SCST Participants for all their efforts•Calif. Crop Improv. UC Davis Mary Voorhees •Harris Moran Olga Maseda •Incotec Ha Ung •Kent Agri Lab Dianne Gilhuly •Mich. Crop Improv. Randy Judd •New York State Seed Lab Michael Loos and Team•SCST Associate Member Phyllis Dawson •Sorghum Partners Terezo Luera •Eurofins STA Connie Obrien •Syngenta Rebekah Wagner •USDA Seed Lab Pattsy Jackson •Utah State Seed Lab Stan Akagi•Monsanto Veg. Seed Lab Oxnard Seed Phys. Lab Team

•Terry Dunfield for helping to organize the project and sending the samples to the labs

•Riad Baalbaki for statistical analysis and project support

Thank you to……..

Questions & Comments