Seed saving and treatment tutorial

[Hellmanns]

I stumbled upon this, and thought I'd post it because of some of the seed treatments mentioned.

Tomato Seed Extraction and Treatment
As was mentioned previously, we do not recommend that growers save their own tomato seeds. With more varieties available as hybrids rather than standard types, the desire to save seed is diminishing. Still, there may be exceptional cases where a grower may wish to maintain a standard specialized variety. Tomatoes (and peppers) are self-pollinated crops. The amount of outcrossing in tomato with neighboring plants is quite low, usually a fraction of 1 percent. (For pepper, natural outcrossing is greater because of wind and insect pollinations; therefore, greater isolation by distance or use of natural barriers is required.) The main reason why seeds need to be properly extracted and treated is the potential contamination of bacterial canker, speck, and spot and tobacco mosaic virus (TMV).
Tomato Seed Extraction
The two methods of tomato seed extraction available are the fermentation process and acid extraction. For seed extraction by the fermentation process, thoroughly crush mature, disease-free fruit. Process the fruit with a tomato juicer and recombine all the juice, seed, and pulp into a suitable container (glass, plastic, or crockery) for fermenting. Fill the container half full and never add water as a substitute for tomato juice. Allow the fermenting process to continue at a temperature not over 70° F (21 ° C) for 96 hours. Stir the fermenting juices at least twice daily to submerge the pomace, which usually floats to the top. Separate the seeds from the pulp by repeatedly filling the container with water, stirring, and pouring off the water with flesh and skin fragments. Flush the seeds several times with jets of water to remove the fruit jelly that adheres to the seed. Spread the seed out on paper and allow them to dry for several days. The seed should then be treated with a fungicide seed-protectant (see Comell Recommends).
Clean seed extracted by mechanical means without fermentation should be acid treated. Immediately treat the wet seeds with an 0.8% solution of acetic acid (1 oz. of 99% acid in enough water to make 1 gal) for 24 hours at or below 70° F (21 ° C). Use USP-grade acid, free from impurities. The seed can be treated loose or confined in a cheesecloth bag for easier handling. Make sure to stir the solution at intervals to ensure wetting all seeds and do not treat over a pound of seed in a gallon of acetic acid solution. Immediately after treatment, dry the seeds and treat with a seed protectant.
Although the fermentation process and acetic acid treatment result in some reduction in germination, this is usually negligible.
Hot Water Treatment
A hot water soak for vegetable seeds, including tomato, has long been recommended. Soak seeds at 122° F (50° C) for 25 minutes in a water bath with agitation to maintain uniform heat. A dairy or laboratory thermometer is recommended for accurate readings. Following treatment, plunge the hot seeds into cold water, thoroughly dry on newspaper, and then dust with a protective fungicide. Freshly harvested seeds withstand the heat treatment better than do one- or two-year-old seed, and treatment should be made as soon after harvest as possible. Hot water treatment will control seedborne bacteria, but will not eradicate TMV. Similarly, it will have no effect on bacteria borne in the embryo (bacterial canker) or TMV contained within the endosperm.
Other Treatments for Virus
No additional information is available for controlling internally borne bacteria for bacterial canker. Several other treatments are available for removal of seedborne TMV: soak seeds for 30 minutes in a 10% solution of household bleach (0.525% sodium hypochlorite, NaOCl); soak for 15 minutes in a 10% solution of trisodium phosphate (Na3P04), often used to soften dried paint brushes; soak for 6 hours in 5% hydrochloric acid (HCl). A more-drastic treatment of using dry heat at 158° F (70° C) for a period of 4 days will inactivate internal virus, but even this treatment is not successful if the virus is in the seed endosperm. For this last treatment, seeds should not be treated within 3 months of harvesting, or germination will be affected.