FIELD CROPS. 845 



Potato improvement and culture, M. Fischer {Fiihlmffs Landw. 



Zt(j., Jfi {1000), Nox. ,S', 2>j>. JOl-m, figs. J^; 9, pj^. 31^3-352, fi.gs. 6; 

 10^ pp. 369-372). — Variations in the development of vines and tubers 

 within the same variety, due to the form, size, or starch content of 

 tubers used for mothers, were studied, as was also the abilit}^ of potato 

 tubers to inherit and transmit individual characteristics. Similar 

 work by the author has been previousl}' noted (E. S. R., 10, p. 1039). 



Tubers weighing between 60 and 70 gm. each were divided into 2 

 lots, the tirst of flat round tubers containing between 18.21 and 19.85 

 per cent of starch, and the other of long round tubers having only 

 11.83 to 13.79 per cent of starch, and these used for seed. Both the 

 vine development and the yield of flat round potatoes were much less 

 than that of the long round tubers. A comparison of 2 typical pota- 

 toes showed that if the yield of vines and tubers from the flat round 

 potatoes be taken as 100, the weight of the vines from the long round 

 tubers would Ije 112 and the weight of the tubers 216. Further 

 experiments substantiated these results, and showed further that flat 

 round potatoes high in starch content used for mothers produced a 

 much larger proportion of tubers of a flat round form and having 

 a high starch content than were obtained from planting long round 

 potatoes low in starch content. 



An explanation is given of the relation between form and starch 

 content of potatoes. The zone richest in starch in potatoes lies next 

 to the outside of the tuber. The inner part of the tuber is much 

 poorer in starch. Other things being equal, the tuber having the 

 greatest outer starch zone in proportion to the inner part or mark of 

 the tuber will be richest in starch. The flat round potato should 

 therefore contain more starch than the oblong form of equal weight, 

 and this hypothesis is substantiated ])y analytical results. The matter 

 of form is therefore considered of importance in selecting tubers for 

 improvement on the basis of starch content. Considerable data are 

 presented showing the relation of form of seed planted and product 

 yielded. 



In a comparison of nitrate of soda and ammonium sulphate, alone 

 and in combination with superphosphate, as a fertilizer for potatoes, 

 the best yields and greatest profits were obtained when the ammonium 

 sulphate was used. Generally superphosphate was used at a loss. 



Experiments were made in planting large potatoes, whole and cut 

 in halves, in comparison with small potatoes. Large potatoes in both 

 cases gave an increased j'ield over planting small tubers. After 

 deducting the cost of the seed, the large potatoes cut in halves 

 resulted in a loss and the large whole potatoes a gain over planting 

 small tu])ers. 



Lime experiments with potatoes on light marsh soil, Lilienthal, 

 {Fuhlimfs Lanckv. Ztg.,1^9 {1900), No. 12, p>p. 459-Jf62,fig. i),— Two 



