xiv CONTENTS 



PAGE 



Marquis wheat .- . . .s. . 136 



Winter wheat breeding at the Minnesota Experiment Station . . . .137 



Breeding beans resistant to Colletotrichum lindemuthianum 139 



An improved strain of tobacco .....'.... 139 



Summary 142 



CHAPTER XI 

 COWPEAS, SOYBEANS AND VELVET BEANS 



Cowpeas (Vigna sinensis) . ....... 143 



Origin . . 143 



Description and inheritance 143 



Some results of selection and crossing 145 



Soybeans (Soja max) ...'.- 146 



Origin 146 



Classification and inheritance 146 



Breeding 148 



Velvet bean (Stizolobium) 149 



Origin 149 



Important characters and inheritance 149 



Mutations 150 



Breeding 151 



CHAPTER XII 

 FLAX AND TOBACCO 



Flax 153 



Species crosses 153 



Inter-relation of factors for flower and seed colors 153 



Inheritance of size characters 156 



Wilt resistance in flax 157 



Methods of breeding 158 



Tobacco 159 



The genus Nicotiana 159 



Parthenogenesis . 160 



Sterility 160 



Color characters -.,......%... v . 161 



Quantitative characters . . . . c . . .'.. .- ; . . . 162 



Environment as a factor in tobacco breeding 165 



Mutations in tobacco ."-.... 167 



CHAPTER XIII 

 COTTON AND SORGHUM 



Cotton . ; -i . . 173 



Classification and inheritance . . . " 173 



Mutations in cotton . .-..-. . . , . . . . . .'.. . . 177 



Cotton breeding .;,... 177 



