14 
BULLETIN 2,, PORTO RICO EXPERIMENT STATION. 
the average size for marketing, their average weight being 135 grams, 
and with the smallest-sized roots suitable for table use, weighing 45 
grams. (PL II, fig. -2.) 
Yield of roots in pounds obtained from planting small and large-sized roots at 
different distances on level land and on ridges. 
Level land planting. 
Ridge planting. 
Test. 
Seed 
roots 
planted. 
Dis- 
tance 
of 
plant- 
ing. 
Yield 
per 
hill. 
Yield 
per 
acre. 
Test. 
Seed 
roots 
planted. 
Dis- 
tance 
of 
plant- 
ing. 
Yield 
per 
bill. 
Yield 
per 
acre. 
1 
Grams. 
135 
135 
45 
45 
Feet. 
2 by 2 
4bv4 
2 by 2 
4bv4 
Pounds. 
3.S6 
6.38 
1.9 
3.42 
Pounds. 
42.095 
17.368 
20. 691 
9.310 
5 
Grams. 
135 
135 
45 
45 
Feet. 
1 
2 
1 
2 
Pounds. 
4.0 
6.6 
3.6 
5 
Pounds. 
2& 372 
2 
6 
23. 410 
o 
7 
25. 524 
4 
8 
17.905- 
It will be noted that the large seed roots produced a heavier yield 
than the small roots: also that the average weight per hill of the 
yield from small seed roots was only 65 per cent of the yield from the 
large seed where different distance plantings and ridge and level land 
plantings are considered. The roots produced from large seed roots 
were also considerably larger than the roots produced from the 
planting of small roots. 
The figures given under ridge planting show that the yield per hill 
where large roots were planted was about the same for plantings 2 
feet apart in ridges and 4 by 4 feet apart on level land; and that 
the yield per hill from planting small tubers was considerably 
heavier where planted in ridges than from the yield secured from 
level plantings. (PL III, figs. 1 and 2.) 
For level land planting at distances of 2 by 2 feet the yield in 
weight of roots harvested per hill was less than when the plantings 
were made at 4 by 4 feet when the seed roots of the same size were 
planted. The total yield per acre, however, was the reverse, the 2 by 
2 feet plantings giving more than double the yield of the 4 by 4 feet 
plantings (PL IV, fig. 1) . The difference in yield was less marked for 
plantings made 1 or 2 feet apart in the row. The roots grown in closely 
planted areas are much smaller than those produced when the plants 
are farther apart. Therefore the profit accruing from close plant- 
ings would not be in proportion to the yield were the crop to be sold 
for table use. because the larger roots bring a higher price in the 
local markets than the smaller ones. Probably the most economical 
plantings would be at distances of 3 by 3 feet. 
The starch content of the fresh roots of the Potato variety is 23.55 
per cent. This feature, together with its heavy yield, makes it a most 
desirable vain. It stows well on level land where the drainage is 
