xiv CONTENTS 



PAGE 



220; Zea Mays indentata, the dent corns, 221; Zea 

 Mays amylacea, the soft corns, 222; Zea Mays sac- 

 charata, the sweet corns, 223; Zea Mays amylea- 

 saccharata, 224; Zea Mays japonica, 225; Zea Mays 

 hirta, 226; Varieties, 227; Discussion of varieties, 228. 



CHAPTER XVI 



THE BREEDING OF CORN . . . 187-210 



The significance of type in corn breeding, 229; De- 

 fects in southern varieties, 230; Barren plants, 231; 

 Tendency to sucker, 232; Methods of improving corn, 

 233. Selection: Start with the best variety, 234; Mass 

 selection, 235; Value of mass selection, 236; Pedigree 

 selection, 237; The initial choice of ears in the field, 

 238; Selecting the breeding plot, 239; Second year, 

 240; Cultivation, 241; Detasseling, 242; Harvesting, 

 243; Third year, 244; Breeding for high and low ears, 

 245; Breeding for composition, 246; Other effects of 

 breeding for composition, 247; Objects of breeding 

 for composition, 248. Hybridization: Objects of hy- 

 bridization, 249; Degrees of relationship among corn 

 plants, 250; The transmission of characters Men- 

 del's law, 251; Dominant qualities in corn-hybrids, 

 252; Effects of inbreeding, 253; Value of crossing 

 varieties, 254; Method of producing cross-bred seed, 

 255. 



CHAPTER XVII 



SOIL AND CLIMATIC ADAPTATIONS OF CORN . . 211-216 



~Soil Adaptations: Soils adapted to corn, 256; Soils 

 not adapted to corn, 257; Modification of soils for 

 corn, 258; Soil type and crop variety, 259. Climatic 

 Adaptations: Factors of climate, 260; Influence of 

 rainfall, 261; Influence of sunshine, 262; Influence of 

 temperature, 263; Length of growing season, 264; In- 

 fluence of climate upon habit of growth, 265. 



