20 THE SEED SUPPLY 



year (Fig. 8). This is the way special strains of the different 

 varieties are developed. 



The reliability of seeds for planting purposes depends upon a 

 number of factors. In the first place, as above indicated, the 

 seeds must have been produced from carefully selected seed plants, 

 grown far enough away from other varieties or undesirable seed 

 plants of the same variety to insure against cross pollination. 

 These seed plants should be given careful attention and every 

 effort made to promote their full development, for a stunted 

 plant is likely to produce inferior seed. 



Cleaning and Curing Seeds. — When the seed is ripe it should 

 be carefully harvested, and threshed or otherwise separated from 

 the plant. In the case of seeds borne in fleshy fruits, like tomatoes 

 or melons, it is necessary to wash the seeds from the pulp. Whether 

 threshed or washed out, all seeds should be spread out in thin 

 layers and allowed to cure as soon as possible after gathering. After 

 the seed is thoroughly cured it may be placed in sacks or other 

 receptacles and stored in a dry place not accessible to mice. 



Seed growers and seedsmen are equipped with special machinery 

 for cleaning and handling the various kinds of seeds. A brief 

 description of the method employed by an extensive grower of 

 tomato seed may be of interest in this connection. The freshly 

 picked fruits from which seed is to be saved are run through a 

 grinder somewhat similar to a cider mill. The ground pulp passes 

 into a revolving drum w^hich takes out the coarsest parts (Fig. 9). 

 The seeds, juice and fine pulp go through the drum and are caught 

 in a barrel. This material is allowed to remain in the barrel to 

 ferment for forty-eight hours. Except- for the fermentation, it 

 would be almost impossible to separate the seeds from the gelat- 

 inous pulp surrounding them. The fermenting mass is put on 

 a sieve mounted in a water tank in such a way that it can be 

 covered w4th water to a depth of a foot or more, and also be at 

 least a foot from the bottom of the tank. After the mass of seeds 

 and pulp is put on the sieve, water is turned into the tank and 

 kept running, while the seeds and pulp are rubbed on the sieve 

 with a hoe. The seeds go through the sieve while most of the 

 pulp floats along the tank to a place where it flows out with the 

 water. However, there is still some pulp with the seeds, so that 

 further Avashing is necessary. The seeds are removed from the 

 tank and placed in a half-barrel or vat. Here they are washed 

 five times, the seeds being allowed to settle and the water being 



