Hayes and Garber - Cucurbit Breeding

METHODS OF BREEDING SMALL GRAINS 115
if the rows harvested are 16 and 20 ft. long, respectively, the
conversion factor will be 0.1.
The rod-rows are about twice as far apart as the rows made by
As from one and one-half to two times as much
a field grain drill.
seed is planted per nursery row as under field planting, the rate
of seeding per acre does not differ materially in the two methods.
These row trials have been shown to give results similar to those
from field tests, although the average yield of the crop is not
the same (Montgomery, 1913; Love and Craig, 1918a).
As has been previously noted, there are two general methods
of work, i. e., the use of single- and three-row plots. Three-row
plots in which the central row only is used to secure yield are desirable
as they help to control mixtures at planting and harvesting
time, overcome competition between nearby varieties and help
in obtaining more dependable data on lodging. They require
more land and the cost is somewhat greater for planting and
cultivating. In sections where soil heterogeneity is very great
it is possible that the use of single-row plots and numerous replications
may be somewhat better than three-row plots and fewer
On land that is well suited for field plot work the
replications.
use of three-row plots and three replications is advised.
may well be
After a strain has been grown for three years it
removed from the row-yield trial and either increased if it shows
promise or discarded if it appears to be of no value. At Cornell
new sorts are introduced to the farmers for trial directly from the
rod-rows.
In many cases the new sort is finally tried in variety
plots planted by the usual field-plot method. This gives an
expression of yield under normal methods of planting and favorable
field conditions.
Summary of Methods of Selection. 1. Determination of the
varieties which possess economic possibilities. These may be
commercial varieties or new introductions.
2. Head selection of these promising varieties.
3. Test of head selections in plant-rows. The very undesirable
strains are eliminated in the field by inspection. A few may be
discarded on the basis of yield or seed characters.
4. Yield determinations of the selections, using three plots of
a single row each, systematically replicated, if seed is available.
5. Continuation of the row test. When land is well suited it
is believed that four systematically distributed plots of three
rows each will give reliable results. Possibly the arrangement