20 



BULLETIN 958, U. S. DEPAETMENT OF AGRICULTUEE. 



produced at the base of the stem, with a gradual increase in length 

 in the upper positions. Since only one variety was included in this 

 phase of the experiment, further studies with other varieties are 

 necessary to determine the general applicability of these results. 



With respect to the size of the tuber, the greatest average weight 

 was produced by the lowest stolons in the 2-stolon and 3-stolon 

 groups; while in the 4-stolon group the maximum production was in 

 the second position, with a gradual decrease in the weight in the upper 

 stolons. Larger numbers of observations, however, are needed to 

 establish the laws governing these relationships. 



SIZE AND CHARACTER OF SEED PIECES AS RELATED TO TUBER PRODUCTION. 



Experiments were conducted to determine to what extent tuber 

 production is influenced by the size of the seed piece; also to deter- 

 mine the relative influence of whole and cut seed. The tubers used 

 for these studies consisted of 1, 2,3, 4, 5, and 6 ounce sizes of the 

 Rural New Yorker variety. One lot was planted whole, another 

 cut in halves, and the remaining lot quartered. The hills were 16 

 inches apart in the row, with rows 36 inches apart. The series was 

 duplicated and the^work relating to the problem under discussion 

 carried on for two years, 1916 and 1917. 



Since the results of these experiments will be published in detail 

 in another report, only a brief summary, which includes the averages 

 of such data as bear directly on this question for the two years, 

 will be given at this time (Tables VII and VIII)..^ 



Table VII. — Relation of the size and bind of seed piece to the number and weight of tubers 

 per hill and per stem as shown in tests of the Rural New Yorker variety of potatoes groivn 

 at Greeley^ Colo., in 1916 and 1917 . - . . . . -^ - , ^ 



Size of tubers. 



Weight 



of seed 



piece 



planted 



(ounces). 



Number 

 of steins 

 per hill. 



Number of tubers. 



Weight' of tubers 

 (grams). 





Per hill. 



Per stem. 



Per hill. 



Per stem. 



Planted whole: 



1 



2 

 3 

 4 



. - 5 . 



1.76 

 2, 60 

 3. 22 

 3.72 

 4.51 

 5.03 



1.81 

 2.25 

 2.50 

 2.63. 

 3.05 



1.49 

 1.63 

 1.85 

 1.96 



4.25 

 6.31 

 ..7.18 

 7.96 

 9. 22 

 10.11 



3. 99 

 . 4.79 



5.29 

 . 5.61 



6.28 



3.35 

 3.63 

 3.94 

 4.13 



2.41 

 2.42 

 2. 23 

 2.14 

 2.04 

 2.01 



2. 20 

 2.12 

 2.12 

 . 2.13 

 2.06 



2.25 

 2.23 

 2.13 

 2.11 



712. 72 

 876. 55 

 886.23 

 952: 92 

 986.59 

 1,030.31 



668. 61 

 764.90 

 815.51 

 . 785.- 78 

 836.54 



663.84 

 673.25 

 724.'84 

 737.56 



404. 80 



2 ounces... 



336. 74 





274. 85 





255.86 





, 218.65 





6 

 1 



n 



2 



3 



\ 

 1 



u 



1* 



204.70 



Tubers cut in halves: 



2 ounces 



368. 89 





339. 32 



4 ounces ... 



326.65 





, 298.45 





274. 14 



Tubers cut in quarters: 



' 444.84 





. 413.20 





390. 91 





375.95 







I 3 The calculations of the data used in these tables are based on the total number of individuals for 1916 

 ' and 1917 rather than the average for the two years, so that they give the true averages for the entire period 

 ' of the experiment. 



