[30 LOCK : STUDIES IN PLANT BREEDING 



in maize also, although in the latter plant the phenomenon 

 is marked by the intermediate form and variability of the 

 hybrid type. 



5. -HEIGHT OF PLANTS. 



This is a character which it is almost impossible to deal 

 with in exact terms owing to its very large dependence 

 upon external conditions. Some of the strains which were 

 made use of were uniformly much taller than others. In F , 

 the height of the cross-breds between such strains was 

 obviously intermediate. In a number of eases the erosswas 

 made between the F 1 plants and the shorter of the parental 

 types. The offspring of this cross showed no such segregation 

 into short and intermediate plants as was to be expected if 

 Mendel's law held good. On the contrary, the plants pro- 

 duced were remarkably uniform in height and showed none of 

 that variability which was shown, for instance, in the offspring 

 of the iioss indent x smooth. It appears therefore that the 

 case must be regarded as one in which homoogonous devel- 

 opment of the germ cell takes place. 



B. — Combinations of Characters. 



In the majority of experiments described under A 1, 2, 3, 

 above, the plants obtained showed as a matter of fact more 

 than one of the pairs of characters dealt with. In all such 

 ■ ;im- ili. evidence showed quite clearly that all the possible 

 combinations of these characters occurred in equal numbers 

 within the ordinary limit- of error. 'The results were in fart 

 - r 1 1 < 1 1 \ m accordance with .Mendel- law. and were uncoin- 



plioated by the phenomena of ooupling, 



The following experiment will serve as an example of a case 

 in which • vera! distincl strains were combined, and in which 

 .ill the following characters were kepi under observation — 



IXy, round, and indented Ivpex o| -rain, and the colours 

 blue, vellou . and white. 



