CONTENTS 



SECTl 



87. 



90. 

 91. 

 92. 



93- 



94. 



95- 

 96. 



Number of grains per ear 

 Proportion of grain to ear . 

 Form for describing the ear 

 The grain .... 

 The hull .... 

 The aleurone layer 

 The endosperm . 

 Form for describing the grain 

 Tubular glands in the embryo 

 Apogamy .... 



PAGE 

 Il6 

 Il6 

 Il8 

 119 

 122 

 122 

 I23 



123 

 I24 

 I24 



CHAPTER V. 



INHERITANCE OF CHARACTERS AND IMPROVEMENT BY 

 BREEDING. 



/ Necessity for Improvement. 



S>^<)7- The object of breeding 



I 98. The necessity for improvement of crops 

 99. Need for increase in the yield per acre 



100. The cause of poor yields 



101. Importance of a perfect stand 



102. Importance of increasing the size of the ear 



103. Average weight of grain per ear 



104. Need for increase in the weight of grain per 



105. Percentage by weight of grain and cob 



106. Effect of depth of grain on yield . 



107. Increasing yield by increasing the number of rows at the butt and tip 



108. Effect of width of sulci on yield 



109. Effect of shape of grain on yield 

 no. Effect of number of rows 

 in. Effect of diameter of cobs . 



112. Need for earlier-ripening breeds 



113. Drought resistance 



114. Disease resistance .... 



115. Loss from weak stalks, shanks, or cobs 



116. Necessity for the production of pure seed 



117. Other desirable points 

 n8. Necessity for development of new breeds 



Inheritance of Characters. 



119. Fluctuations ...... 



120. Characters may be inherited 



121. Importance of a knowledge of the laws governing the 



characters ....... 



122. Inheritance of characters in maize follows Mendelian 



123. Reproduction and transmission of characters 



124. Mechanism of transmission 



125. The zygote 



126. The homozygote 



127. The heterozygote 



128. Unit-characters . 



129. Allelomorphic pairs of unit characters 



130. Dominant and recessive allelomorphs 



131. Interaction of unit-characters 



132. Repulsion and coupling of characters 



133. Xenia 



134. Splashed purple colour of the aleurone layer 



135. Gametic segregation 



Law 



ion of 



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 130 



131 

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137 



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