48 Nebraska Agricultural Exp. Station , Research Bui. 20 
pollination. Almost perfect fertilization of the ears resulted, 
indicating rapid development of the pollen tube. Following 
fertilization, the silk shrivels up at its base, thus cutting off 
further sap supply. Thereupon the silk withers and dies, the 
first reliable external evidence of which is observed on the silks 
in from forty to seventy hours after pollination. 
HOGUE’S YELLOW DENT (CLASS IX) PURE LINES AND HYBRIDS 
PURE LINES 
These pure lines were derived from the 1907 progeny of 
the four highest yielding ear-to-row strains determined in a 
two-year (1906-1907) test with 204 individual ears of Hogue’s 
Yellow Dent corn. These four ear-to-row strains were assigned 
the stock numbers 5, 6, 15, and 17. Three well-developed ears 
were selected from each of these four strains and planted indi- 
vidually in small partially isolated increase plats, in 1908, consti- 
tuting twelve inbred strains. Beginning with 1909, single ears 
from each of the strains were planted in adjacent rows for con- 
trolled self-fertilization. In 1911 four of the inbred strains had 
become sterile and another was lost in 1915. Figure 12 shows 
representative plants of the eight surviving strains in 1915. The 
plant to the left is typical of the original variety, while the others 
from left to right are strains Nos. 1, 2, 4, 5, 8, 9, 10, 12. (Table 
No. 14.) Typical ears borne by the strains in 1916 are shown in 
figure 13. 
Table No. 14 gives the comparative yields and plant char- 
acters (1916) for seven strains, and for the original Hogue’s 
Yellow Dent. Considerable variation is seen to exist in the pro- 
ductivity of different strains, tho the best one yielded only 41 
per cent as much as the original. Comparing the average of the 
seven inbred strains with the original Hogue’s Yellow Dent 
corn: (1) The date of tasseling was one day earlier; (2) the 
date of ripening was three days earlier; (3) the stalk height 
was 63 j:>er cent; (4) the ear height was 53 per cent; (5) the 
leaf area was 56 per cent; and (6) the grain yield was 27 per 
cent as large. Yield tests of the individual strains have not 
been made in other years, tho they have been compared in com- 
posite with the original each year, beginning with 1911. The 
annual composite results are included in Table 25 on page 72. 
During the years 1911, 1912, 1913, 1914, 1915, 1916, and 1917 the 
pure lines yielded respectively 47, 35, 13, 23, 34, 28, and 30 per 
cent as much grain per acre as the original corn. 
In 1914, after five years of selfing, these strains had appar- 
ently all attained the pure elemental state, since their progeny 
