CONTRIBUTIONS TO THE GENETICS 



OF PISUM 



III ': INTERNODE LENGTH, STEM THICKNESS AND 

 PLACE OF THE FIRST FLOWER 



BY HANS AND OLOF TE DIS 



SVALÖF 



INTRODUCTION. 



THE data recorded in this paper have heen collected hy H. Tp:din 

 in 1919 and 1920. Unfortunately, in both years the peas here 

 at Svalöf were very much damaged by bad weather and insects, and 

 seed enough to raise an F3 of the different crosses was not obtained. 

 Thus the results reached were thought valueless, and no closer exami- 

 nation of the numbers wa,s made. In this year, however, new crosses 

 are to be made, in order to try to get a solution of the problems con- 

 cerning heredity of growth and earliness in peas. Hence the data 

 obtained in 1919 and 1920 have been worked through by O. Tedin 

 in order to see if they might give some useful hints about the new 

 investigation. It soon became evident that the problems here studied 

 are far from being solved, and that they are perhaps still more com- 

 plicated, than has been suggested by previous investigators. As three 

 or four years, however, are wanted until more definite results may 

 be ol)tained, and as the results already reached perhaps may throw 

 some light upon the problems involved, we have thought it con- 

 venient to give a short account of the investigation, which was origi- 

 nally commenced in order to control the results obtained by Keeble 

 & Pellew (1910), whose interpretation will be discussed in some 

 respects in this paper. A full list of the literature upon inheritance 

 of growth in Pisum is given by White (1917), and is not repeated here. 



METHODS. 



The average length of the internodes of the single plant has 

 been determined in the following way: from where the internodes have 



^ The papers of H. TEorx (1920 & 1923) on flower and seed colour in peas 

 are to be considered as Contributions I and II. 



