INHERITANCE— IMPROVEMENT BY BREEDING 195 



" In considering experiments in the inheritance of size CHAP. 



characters in maize, we must remember that fluctuations are 

 present, and that often many genotypes are present in one 

 parent." 



1 53. Inheritance of Height 0/ Plants. — The results of East 

 and Hayes's investigations, as far as described in their paper 

 (i), show segregation from the lowest class range of the shorter 

 parent to the highest class range of the taller parent, but they 



do not consider these 



segregates as pure types, 

 and " their behaviour in 

 further generations is still 

 problematical ". In every 

 case the comparative size 

 of the coefficient of varia- 

 tion was at least 50 per 

 cent higher in the F„ 

 generation than in the 

 F, generation (see Table 

 XXXVIII). The Fj 

 generation is not inter- 

 mediate between the two 

 parents, but is nearly as 

 high as the taller parent. 

 This fact, they point out, 

 is not to be regarded as 

 in any way connected 

 with dominance, but is 

 due to the increased 

 vigour of the maize plant 

 which comes from cross- 

 ing, as pointed out by East (3) in a previous paper. 



An entirely different case has come under the observation 

 of the writer, in the F 1 progeny of a cross between Hickory 

 King (Fig. 81 A) and Wills Gehu (Fig. 8 IB). 



The relative height is shown by the walking-stick which 

 stands alongside, at the same relative distance from the camera 

 as the stem of the plant, in each case. 



In this case the Fj plants, Figs. 82A and B, show the dwarf 

 habit of the Wills Gehu parent, and little, if any, increase 



13* 



v. 



Fig. 8ia. — Inheritance of size characters. 

 Hickory King, 8 to 9 feet high. (Type used 

 to produce cross shown in Fig. 82 and grown 

 the same season.) 



