102 Inheritance in Barley 



this form, the data of several crosses. In this table, for every cross, the 



first row shows the actual numbers of plants in the (A), heterozygote, 



and (F) classes. The second row contains these numbers expressed as 



percentages, while the third row shows the standard errors of these 



percentages due to fluctuations of sampling. The standard errors 



have been calculated on the basis of an expectation of 1:2:1, i.e. 



25 7o '• 50 °/^ : 25 °/^. The table contains twenty-four percentages, and 



in five cases only does the difference between observed and calculated 



percentages exceed the standard error, whereas some seven cases might 



be expected. The cases are as follows : 



Cross 57 ... 21 -0% instead of 25 ±3-2 



Cross 5 ... 21-6% „ 25±2-9 



Cross 5 ... 5I:-2% „ 50±3-3 



Cross 4 ... 41-8% „ 50 ±3-4 



Cross 4 ... 29-0% „ 25 ±3-0 



It is not easy to sort such an F.^, for type of lateral floret. In stunted 

 plants the difference between (F) and "heterozygote" is much obscured. 

 Consequently there seems justification for stating that the results of 

 the crosses indicate the proportions (A) : heterozygote : (F) = 1:2:1 

 in jPa- The combined results of the crosses (last row of Table II) show 

 no deviation as great as the relevant standard error. 



To summarise these conclusions it may be said that : 



(a) Six-row and two-row (distichum) barleys differ in regard to 

 form of lateral floret by one factor only. 



(/9) The heterozygotes of F^ resemble the F^ plants. Like them 

 they are subject to fluctuations induced by environment. These fluctua- 

 tions result in apparent differences, but constantly different groups 

 cannot be found. 



Blaringhem (10) has introduced novel views in connection with 

 crosses between 6-row and 2-row barleys. In the appendix (p. 106) 

 attached to this paper will be found some observations upon his views. 



V. Ubisch (6) has made extensive observations upon 6-row x 2-row 

 crosses and has formulated a hypothesis on the assumption of a two- 

 factor difference between the parents in regard to form of lateral floret. 

 He found that the laterals of the F^ plants, like those of the F^ hetero- 

 zygote plants, were much influenced by conditions. The classification 

 adopted for the Fz was 



zwei-zeilig : zwei- bis sechs-zeilig : sechs-zeilig. 



The middle class was thus defined : " Es hat sich als zweckmassig zur 

 Analyse herausgestellt, alien Typen, die gelegentlich fertil sind, als 

 zwei- bis sechszeilig zu bezeichnen." 



I 



