HEREDITY AND VARIATION 



255 



that will breed more plants like itself. LiitluT Burbaiik, the 

 great hybridizer of California, destroys tens of thousands of plants 

 in order to get one or two with the charac- 

 ters which he wishes to preserve. Thus he 

 is yearly adding to the wealth of this 

 country by producing new plants or fruits 

 of commercial value. A number of years 

 ago he succeeded in growing a new va- 

 riety of potato, which has already en- 

 riched the farmers of this countrj^ about 

 $20,000,000. One of his varieties of black 

 walnut trees, a very valuable hard wood, 

 grows ten to twelve times as rapidly as 

 ordinary black walnuts. With lumber 

 yearly increasing in price, a quick grow- 

 ing tree becomes a very valuable com- 

 mercial product. Among his famous 

 hybrids are the plumcot, a cross between 

 an apricot and a plum, his numerous va- 

 rieties of berries and his splendid '^ Climax" 

 plum, the result of a cross between a 

 bitter Chinese plum and an edible Jap- 

 anese plum. But none of Burbank's 

 products grow from seeds ; they are all produced asexually, from 

 hybrids by some of the processes described in the next paragraph. 



The Department of Agriculture and its Methods. — ■ The Depart- 

 ment of Agriculture is also doing splendid work in producing new 

 varieties of oranges and lemons, of grain and various garden vege- 

 tables. The greatest possibilities have been shown by department 

 workers to be open to the farmer or fruit grower through hybrid- 

 izing, and by budding, grafting, or slipping. 



Budding. — If a given tree, for example, produces a kind of fruit 

 which is of excellent quality, it is possible sometimes to attach parts 

 of the tree to another strong tree of the same species that may not 

 bear good fruit. This is done by budding. A T-shaped incision 

 is cut in the bark ; a bud from the tree bearing the desired fruit is 

 placed in the cut and bound in place. When a shoot from the 



In hybridizing, all of the 

 flower is removed at the 

 line (W) except the pis- 

 til (P). Then pollen 

 from another flo\v(>r of a 

 nearly related kind is 

 placed on the pistil and 

 the pollinated flower 

 covered up with a paper 

 bag. Can you explain 

 why? 



