4 ASSOCIATED SEEDS, INC. 
CORN 
Zea mays 
Until recent times, the development of corn varieties adapted to particular purposes and con- 
ditions of growth depended on natural mutation and selection by growers. Now, however, the 
new science of plant breeding has been applied to the building of hybrid varieties, with most 
satisfactory results in uniformity, yield, disease resistance, and adaptability to the soil and 
climate of definite areas, so that each season the proportion of hybrid corn is steadily increasing 
over that of the old open-pollinated types. 
A hybrid is defined as the first generation of a cross between strains of different parentage and 
involving one or more inbred lines or their combinations. A single cross hybrid is made by 
crossing two inbred lines, and a double cross from the mating of two single cross parents. A 
three-way cross comes from an inbred and a single cross. A top cross has for parents an 
inbred and an open-pollinated variety; a double top cross has a single cross and an open-polli- 
nated variety for parents. Of these five types the double cross hybrids are most generally used. 
The purpose of inbreeding, that is, the fertilization of plants with their own pollen, is to 
emphasize desired characters such as size, shape, uniformity, disease-resistance, etc., and to 
eliminate those that are undesirable. Continued inbreeding of a single group of plants requires 
a high degree of skill, patiently exercised for years and with the possibility that it may not 
lead to profitable results. The next step is crossing by means of controlled pollination, which 
must be conducted with equal care. The first generation seed of any hybrid gives the maxi- 
mum benefits from hybridization. The next generation, however, is not satisfactory for seed, 
as the hybrids are unstable in reproduction and begin to break up into the original and diverse 
lines from which they were developed. 
From the foregoing, three deductions follow naturally. (1) Hybrid seed must be procured 
anew each year, not saved. (2) It is bound to cost a little more, though it more than amply 
repays its cost. (3) It should be obtained only from a trustworthy and completely reliable 
source, since its value cannot be judged by its appearance. 
The following list comprises, first, a comprehensive selection of the open-pollinated varieties 
which experience has shown to be best adapted to the needs of Texas and other South- 
western growers, followed by seven outstanding hybrids developed through a program of breed- 
ing, selecting and testing by the Texas Agricultural Experiment Station. Others are in course 
of production and will be announced when available. We confidently recommend them for 
trial by our customers, predicting increased yields and greater uniformity, easier harvesting, 
and improved quality of grain for milling and feed. 
The number of days indicated for each variety represents the average over different areas and 
different years. These figures are naturally subject to variation and are primarily intended for 
purposes of comparison. 

White June: the improved Asgrow strain 
