PLANT BREEDING 319 
generations, the garden-plots containing descendants of 
the new hybrid must be rogued, or gone over plant by 
plant, in order to destroy all individuals but those of the 
desired variety. In the case of wheat, after the fourth 
generation some plants are usually to be found that will 
“come true to seed.” 
398. Results of Hybridizing the Grains. — In this coun- 
try especial attention has been given to hybridizing In- 
dian corn and wheat. Some valuable varieties of corn have 
already thus been obtained and many more seem likely to 
Fic, 223. 
a, a stoneless wild plum; 8, e, d, fruit of hybrids of a with the French 
prune. (All drawn to the same scale.) 
be secured. Hybrid wheats are of importance for use as 
stocks from which to breed and select. Much time is now 
spent at the agricultural experiment stations of the great 
wheat-growing states in hybridizing wheats for breeding 
purposes. 
399. Results of Hybridizing Small Fruits. — The most 
familiar hybrids among small fruits are grapes. Very 
likely the Delaware and the Catawba are hybrids, and the 
Salem, Brighton, and Diamond certainly are. Many varie- 
ties are directly or remotely descended from hybrids be- 
tween the European wine grape and our northern fox 
grape, two wholly distinct species. 
