CONTENTS 



SECTION 



136. The reason for segregation in mathematical proportions 



137. Monohybrid ratios 



138. Dihybrid ratios . 



139. Trihybrid ratios . 



140. Inheritance of colour 



141. Yellow endosperm 



142. White starchy endosperm 



143. Inheritance of characters which affect the growing plant 



144. Pericarp colour .... 



145. Somatic variation in pericarp colour 



146. Silk colour ..... 



147. Red cob-colour .... 



148. Glume colour .... 



149. Development of " pods " 



150. Inheritance of ligule and auricles 



151. Physical condition of the starch . 



152. Size characters .... 



153. Inheritance of height of plants . 



154. Inheritance of abnormal dwarfness 



155. Inheritance of length of ears 



156. Inheritance of size and weight of grain 



157. Inheritance of row numbers 



158. Four-rowed ears . 



159. Inheritance of fasciated and lobed ears 



160. Inheritance of laterally-branched ears 



161. Striped leaves .... 



162. Difficulties encountered in studying inheritance in maize 



PAGE 

 l80 

 182 

 182 

 I84 

 187 

 187 



igo 

 190 

 igr 

 191 

 191 

 191 

 192 

 192 



!95 

 197 

 197 

 199 

 199 

 206 

 206 

 206 

 207 

 207 



163. 

 -164. 

 165. 

 166. 

 167. 

 168. 

 r6g. 

 170. 

 171, 

 172. 

 !73- 

 174. 



175. 

 r 7 6. 

 177. 

 178. 

 179. 

 180. 



183. 

 rS4. 

 185. 

 r86. 

 1S7. 

 188. 

 189. 

 190. 

 191. 

 192. 



Methods of Plant Breeding. 



A few general principles ......... 208 



Methods of pi ant, breeding 209 



Selection of parents .......... 210 



Effect of inbreeding .......... 211 



Improvement in yield by use of first-generation crosses . . . 213 



Fundamental points of seed selection ....... 213 



Correlation of characters ......... 213 



Desirable stalks ........... 215 



Desirable leaves ........... 215 



Desirable ears ........... 215 



Desirable cobs ........... 216 



Desirable grains ........... 216 



Fancy points ........... 217 



Methods of selection .......... 218 



Importance of care in selection ........ 2ig 



Field selection of parent ears ........ 220 



Seed-room selection of ears ........ 222 



Character of the grain •-......, 224 



Selection by continuous performance-record ..... 225 



Method of propagation ••••..... 226 



The breeding plot .......... 229 



Devices to prevent or detect cross-pollination ..... 229 



Production of new types by artificial cross-pollination . . . 230 

 Reciprocal crosses . . . . . . . . . .231 



Method of cross-pollinating ••••.... 231 



Collecting the pollen .......... 231 



Covering the silks .......... 233 



The Fj plants ........... 233 



The F 3 plants ........... 234 



Improvement by breeding is slow at first 234 



