88 University of California Publications in Botany [Vol. 5 



IV. Germination of the seed 96 



(1) In the germinating case 96 



(2) In the propagating house 98 



(3) Total germination and discussion of rates of germination. 99 

 V. Development of Seedlings 101 



(1) Early development of seedlings 101 



(2) Number and condition of plants in the field 101 



VI. Appearance of the plants in the field 103 



(1) Scheme of grouping 103 



VII. Discussion of inheritance of characters according to weight of 



seed 106 



(1) Shape, size and weight of parental seeds of 1906 and 



1907 106 



(2) Correlation between inheritance of characters and weight 



of seed 107 



VIII. Summary of results 108 



IX. Discussion of results 109 



I. INTRODUCTION 



The investigation herein reported Avas undertaken for the 

 purpose of determining the possible relationship between the 

 physical characteristics of pedigreed seed and the segregation of 

 the so-called " unit characters" as manifested in the plants grown 

 from such seed — especially the relation between the weight of hy- 

 brid tobacco seed and the appearance of the ¥^ generation individ- 

 uals produced therefrom. The introduction of evidence to support 

 a strict Mendelian interpretation of experiments in plant breed- 

 ing, the results of which fail to show segregation in accordance 

 with any of the accepted formulae, has very naturally reached 

 such a point that some interest must be attached to the amount 

 of germination, viability, and general physical constitution of 

 the seed from which the pedigreed plants have developed, or 

 are to develop. Indeed, in any scientifically conducted experi- 

 ment in plant breeding, there should be more attention paid to 

 such supplementary data as the variations in color, size, weight, 

 and germination of the seed. 



There seems to be no mention throughout the literature of 

 any recorded data in this particular connection (see, however, 

 Groth, 1911, part I, page 9), though a great number of practical 

 experiments, dealing with the relation between the physical char- 

 acteristics of seed and the vigor, etc., of the resulting plants. 



