PAPERS ON BIOLOGY AND AGRICULTURE 109 



GROWTH AS RELATED TO SPECIFIC GRAVITY 

 AND SIZE OF SEED* 



MARY E. RENICH 



TABLE OF CONTENTS 



Page 



I. Introduction 109 



11. Materials and Methods: 



1. Selection and Separation of Seed Used 112 



2. Treatment of Seedlings 113 



III. Discussion: 



1. Relation of Growth to Specific Gravity of Seeds, at 25^ C 116 



a. Water Culture 116 



b. Soil Culture 119 



2. Relation of Growth to Size of Seed at 25 = C 122 



3. Temperature in Relation to Specific Gravity and Size 



of Seed 124 



4. Some Comparisons of Seedlings in Water and Soil 126 



5. Equation of Growth 126 



6. Correlation of Weight and Position of Cotyledons 126 



7. Quintile Distributions 127 



IV. Summarj' 130 



V. Bibliography 132 



\1. Tables 133 



VII. Plates Ill 



I. INTRODUCTION 



The influence of the size and of the weight of seed on the 

 resulting crop has been a subject of investigation for many 

 years. The evidence gathered from the literature in this 

 field seems to show that large, heavy seeds give the best re- 

 turns. A considerable number of investigators find that 

 their results are rather conflicting. Deherain et Dupont 

 (4) maintain that it is only when the difference in the 

 weights of the seeds used is great, that there is a 

 definite advantage in favor of the heavier seed. Meyer, 

 C. H. (13) says that the question of advantage in the 

 use of large and small seeds as associated with yields is 

 inconclusive. Leighty, C. E. (11) condemns the method of 

 selecting the largest seed without consideration of the char- 

 acter of the mother plant; and Love. H. H. (12) concludes 

 from his results that the heavy grains of wheat and oats 

 come from the tallest and heaviest yielding plants. Johann- 

 sen, W. (9) in his work on inheritance of weight shows 

 that, in a population of beans, the heaviest daughter-beans 



•This paper is the thesis, somewhat condensed by the omission of several tables, 

 submitted by the author in partial fulfillment of the requirements for the degree 

 of Doctor of Philosophy. 



