GRA.SSES OF IOWA. 



121 



In regard to several other grasses Mr. Thompson* states of 

 oats, clover, ray grass, corn, Avena orientalis, Arrhenatherum, 

 avenaceum and Medicago saliva that sulphate of iron acts injuri- 

 ously upon the development of the roots. Most of the earlier 

 references are fully given in the review in the paper quoted 

 by Pammel and Stewart as well as Evans. 



Physical. — Maldiney and Thouveninf have made some experi- 

 ments to determine the influence of X-rays upon germination. 



In the case of Panicum miliaceum the writers found that when 

 under the influence of X-rays for two hours germination was 

 hastened. The amount of moisture and physical condition of 

 the soil are most important factors during the process of ger- 

 mination. 



SEED SELECTION AND THE CROP PRODUCED. 



There can be no question that the careful and intillegent 

 selection of seed influences the crop. This has been amply 

 demonstrated in a great many crops. It is a well-known fact 

 that the European sugar beet growers carefully select "the 

 mother beet" by making tests of the amount of sugar present. 

 It has also been shown by Wiley t that by a careful selection of 

 sorghum canes, with a high percentage of sugar, the standard 

 has been raised. Mr. Oma Carr§ shows that in certain varie- 

 ties the per cent of sugar content was increased as follows: 



Wiley records several pedigrees of the improved canes and 

 the amount of sugar they contain and gives a discussion of the 

 results. Hicks and Dabney|| have shown that there is a marked 

 increase in the weight of seedlings of radish, early Amber cane, 

 Kafir corn, winter vetch, sweet pea, rye, oats and barley from 

 the heavier seed, that there is an increase in the root develop- 

 ment when seeds are planted In case of heavier peas early 

 flowering is noticed. Webber says: "Mr. Henslow^ found 



Dorpater 



*Deber die Wirkung von Schwefelsaurem Elsenoxydul auf die Pflanze. 

 Naturforscher-Gesellschaft. 18: 96-101. 



+Ue I'influence des rayons X sur la germination. Revue generate de bot. 10: 

 ^Experiments with sorghum. Bull. U. S. Dept. Agrl. Dlv. Ohem 29: 52. 39: 25. 

 iExperiments with sorghum. Bull. U. S. Dept. Agrl. Div. Chem. 40: 28. 

 DYear book. U. S. Dept of Agrl. 1896: 305. 

 lYear book. U. S. Dept. of Agrl. 1896:.89. 



81. 

 40:27. 



