408 



BULLETIN No. 127. 



[August, 



climate. He argues that this in itself is a proof of hereditary trans- 

 mission of a character acquired in the first place. Like results had 

 been obtained already by Martinet (70). 



Hess (56) concludes that selection of vigorous mother plants 

 which produce many tubers will bring about an improvement in 

 the yield. His data do not warrant a definite statement. 



Brumer (14) in 1891 came to the same conclusions, but he ob- 

 serves that the choosing of high-yielding plants only increases the 

 yield when planted on a fertile soil. When planted on a poor soil, 

 such a strain will set many tubers but they will be small. He ob- 

 serves further that the use of vigorous, healthy plants as mother 

 plants gives a noticeable protection from disease. A summary of 

 his results is shown in the following table : 



In 1895 Sempolowski (91 a) reported an investigation in which 

 he selected his seed potatoes from mother plants producing at least 

 fifteen tubers, and planted them in comparison with such ordinary 

 stock as would usually be planted. His yield from the selected 

 tubers was 25285 Kg. per hectare compared with 24555 Kg. per 

 hectare from the ordinary seed. 



The experiments of Liebscher in which he came to negative 

 results regarding hereditary transmission of tuber variations were 

 continued at his death by von Seelhorst. The latter concluded in 

 1897 that their experiments up to that time contained some grave 

 errors, such as unequal depths of planting, non-uniformity of seed 

 as to type and size, etc. These errors were his warrant for start- 

 ing new experiments which he has reported in three notable papers 

 (89, 90, 91). 



The experiments were with four varieties and I give below the 

 collected results for the last year, 1903. The tubers used for seed 

 are divided into two classes, large and small, which, as can be seen 

 does away to a large extent with any influence due to differences in 

 weight of the seed used. Determinations of starch in seed tubers 

 and crop were also made and there was a notable transmission of 

 starch to their progeny from high starch tubers. 



