Hayes and Garber - Cucurbit Breeding

166 BREEDING CROP PLANTS
variability.
A careful survey of experimental studies does not
support this contention. The development of the shadegrown
tobacco industry in the Connecticut Valley is of interest
in this discussion. This shade method first originated in Florida
in 1896 and was tried experimentally in Connecticut through
cooperation of the Connecticut Experiment Station and officials
of the Bureau of Soils. In 1900 one third of an acre was grown
and the crop sold at an average price of 72 cents per pound.
A considerable acreage was grown in 1901 and the crop sold
at public auction at a much higher price per pound. Indiscriminate
introduction of unselected seed from Florida was
practiced and in 1902 over 700 acres were grown under shade in
Connecticut. The result was a disastrous failure, owing to a
lack of knowledge of methods of handling and to the use of unselected
seed. By further study of handling and through careful
selection in which artificially self-pollinated seed was saved,
the industry was placed on a firm foundation. This latter work
was carried on by the Bureau of Plant Industry (Stewart, 1908).
A knowledge of Cuban methods shows that imported Cuban seed
is a mixture of many types. Some experiments have shown that
the breaking up alluded to is an expression of the different
hereditary qualities of the parental seed plants. In 1912 Hasselbring
grew a number of pure lines of tobacco in Michigan which
he had formerly grown in Cuba. No evidence of breaking up of
type was observed and whatever changes occurred in a pure line,
owing to the new conditions, were uniformly exhibited in all
plants of the pure line. Similar conclusions were reached from
the immediate introduction of individual seed capsules of different
tobacco plants from Cuba and their subsequent growth under
shade in Connecticut (Hayes, 1914). Careful studies at Pusa,
India, convinced the Howards (1910a) that new conditions
did not cause a breaking up of type. They ascribed the apparent
variability of new introductions to cross-fertilization, which
was shown to occur frequently in tobacco.
Although there have been some differences of opinion as to
the cause of variability of new introductions, there is uniformity
of belief regarding the methods of obtaining purity of type.
Artificial self-pollination gives uniformity, and continued
self-fertilization produces no harmful effects. This method was
strongly recommended by officials of the United States Department
of Agriculture (Shamel and Cobey, 1907) and by the different