The Twentieth Century


other than those directly served by the primary stations, second-
ary regional introduction stations have been planned. At these
secondary stations, crops which have shown themselves adaptable
to that area will be grown. This will relieve the primary stations
of part of their repropagating burden and place the plants where
they can thrive best.
 Under the provisions of the Research and Marketing Act, five
exploring expeditions were sent into the field between 1946 and
1948. Disease-resistant potatoes were secured from Mexico by
D. S. Correll. Varieties of Mexican and Guatemalan cotton were
found which have plant and fiber characteristics that may prove
helpful in improving American upland cotton. Forage plants
and wild and cultivated strains of peanuts came from South
America. J. R. Harlan went to Turkey to find vegetables, forage
plants, oil plants, and cereals for a domestic breeding program.
In 1949, W. N. Kelz, was searching India for cereals for winter
forage and plants with potential industrial uses. From these
expeditions more than 4,500 introductions had been obtained
and distributed to thirty-eight states by 1948.

 LOOKING TO THE FUTURE
 It seems certain that plant research and introductions of the
future not only will contribute new food crops, but will aid as
well the progress of mechanical and chemical technology. Often
when experimenters develop disease-resistant plant varieties, the
disease organisms in turn adjust themselves by developing new
virulent strains. Redesigning plants with the desirable character-
istics of many species fused into a single new variety offers a
limitless challenge to plant workers. Like the introductions of
Colonial days, the plants of tomorrow become America's crop
heritage for future generations.