HYBRIDIZATION 563 
ceptible to Rust, with Wheat, immune to Rust but Jess desirable 
in other features, a type of Wheat having the Rust resistance 
of one parent and the desirable features of the other has been 
obtained. Cotton producing longer and better lint has been 
obtained by crossing the Sea Island Cotton with the Upland 
Cottons. There are many instances in which more desirable 
races have been secured through hybridization. 
Fic. 486. — The effect of threc degrees of relationship in breeding Corn. 
Nos. 3 and 4 are pure strains from seed-stock inbred for three years. No. 2 
is from a close-fertilized seed-stock, the plants each year being fertilized with 
pollen from sister plants grown from the same ear. No. 1 is from seed-stock 
that has been cross-fertilized for three years. After Montgomery. 
The greatest advantage arising from hybridization is among 
plants propagated by vegetative methods, as by tubers, bulbs, 
cuttings, layering, grafting, etc.; for in these cases the progeny 
is simply a continuation of the hybrid individual and not the 
result of the fusion of gametes. Many berries, vegetables, fruit 
trees, and ornamental plants are hybrids. By crossing different 
kinds of Strawberries, hybrids more desirable than either of the 
parents have been obtained, and since they propagate by run- 
