1218 EARLE V. HARDENBURG 



tuber. As early as 1886, Samuel Johnson (1886) compared the yields 

 from whole and half tubers and from three-, two-, and one-eye pieces, and 

 found that, whereas the whole tuber gave the highest total yield, the 

 three-eye piece gave the highest marketable yield. Two years later, 

 comparing the same types of seed, Johnson (1888) obtained a consistent 

 gain in yield with each increase in size of seed, and a decrease in percentage 

 of stand with each decrease in size of seed. Johnson did not report 

 whether his highest total yields were also the highest net yields. 



Taft (1892), in a three-years test, compared the efficiency of various 

 rates of planting, by planting whole, half, quarter, and eighth tubers, 

 and single-eye pieces, equidistant in the row. His net yields increased 

 up to and including the half tuber, altho the highest total yield came from 

 whole seed. Adams (1889), using whole, half, two-eye, and one-eye seed 

 pieces, obtained an increased total yield up to and including whole seed, 

 with the greatest marketable yield from two-eye pieces. He did not report 

 in terms of net yield. Green (1887) reported a two-years average test of 

 the yields from one-eye, two-eye, half, and whole seed pieces as increasing 

 with the size of piece used, but made no mention of the net or the market- 

 able yields or of the rate of planting. Hutcheson and Wolfe (1917) made a 

 three-years comparison of the yields from single-eye, half -ounce, one- 

 ounce, and two-ounce pieces. Whereas both total and marketable yield 

 increased up to and including the two-ounce piece, the increased yield 

 from the two-ounce over that from the one-ounce piece was not sufficient 

 to warrant the use of pieces larger than one ounce in weight. Aicher 

 (1917) and Welch (1917), in their duplicate experiment covering three 

 years, concurred in the results showing the highest total yield to be from 

 whole seed and the highest marketable yield from quartered seed pieces, 

 in a comparison of whole, halved, and quartered seed pieces. These 

 investigators were agreed also that the number of stalks per hill increased 

 with the size of piece planted, a fact which probably accounts for the smaller 

 percentage of marketable tubers from the largest seed. 



Appleman (1918) tested the influence of weight of seed piece on yield 

 by varying the weight from 0.08 to 1.75 ounces in the variety McCormick 

 and from 0.61 to 1.46 ounces in the variety Irish Cobbler. To give due 

 consideration to rate of planting in such a test, he showed how this vari- 

 ation in McCormick increased the amount of seed from 1.1 to 24.96 

 bushels per acre. He obtained, in both varieties, an increased total yield 

 with each increase in weight of the seed piece. 



Zavitz (1916) has furnished perhaps the best contribution to the study 

 of this factor. In ten tests, covering five years, he compared one-sixteenth-, 

 one-eighth-, one-quarter-, one-half-, one-, and two-ounce seed pieces, the 

 rate of planting varying from 1.3 to 41.2 bushels per acre and the number of 

 eyes in each set remaining constant. With no seed piece weighing more 

 than two ounces, Zavitz found increased net, marketable, and total 



