30 PLANT BREEDING 



to pollinate the seed ears. In other words both parents of the 

 seed corn should be vigorous and productive. The barren stalks 

 may be cut out or their tassels cut off before any pollen is scat- 

 tered by them. 



To avoid cross pollination with nearby fields, seed corn growers 

 plant their fields at long distances from other fields. They some- 

 times grow belts of willows or other trees between the different 

 varieties. 



The Ear-Row System of Improving Corn. — Suppose we select 

 the ten best ears of corn from a given garden or field. We may 

 plant the seed from each of these ears in a row by itself. Compare 

 the yield from each of these rows and select the best ears for seed 

 from the best row. If desired, we may continue the ear-row method 

 and continue to select from the best, indefinitely. Home gardeners 

 will find this method entirely practical and beneficial. 



Size and Weight of Seed. — If several samples of garden seeds 

 are sorted by means of sieves into different sizes, it will be found 

 that the largest seeds will give best results. With grains which are 

 usually weighed instead of measured when purchased, it has been 

 found that those which weigh heaviest for the measured bushel are 

 most productive. 



The lesson to' be learned here is that we should select the heav- 

 iest and best seeds when saving or buying seeds to plant in our 

 home gardens. 



Sifting and Weighing. — It pays to sift seeds through sieves 

 which will separate the large seeds from the small. Not only will 

 the best seeds be thus obtained for planting but many weed seeds 

 may be eliminated. When grass and clover seeds are to be sown 

 in the home grounds, they should be carefully sifted and weighed 

 to determine the proportion of seed and chaff. Light seeds may 

 be blown out by means of the fanning mill or other forms of seed 

 cleaners. 



HOME PROJECTS, FIELD AND LABORATORY EXERCISES 



1. Studying Variation. — -In a thick patch of weeds or other plants, note 

 the variation in height, size of stem, number of leaves, color of foliage, and 

 other characteristics. Explain as many of these differences as you can. 



2. Extreme Variation. — Find examples of extreme variation in wild or 

 tame fruits, or other plants. Of what advantage could these be in developing 

 new varieties or strains? 



3. Selection by Growers. — Visit truck gardeners, fruit growers, or pro- 

 fessional plant breeders. Ask them to show results of careful selection in de- 

 veloping new strains. 



