Hayes and Garber - Cucurbit Breeding

CHAPTER XVIII
FRUIT BREEDING
The improvement of fruit crops offers an interesting field of
study for the trained investigator. Many fruits are in a complex
heterozygous condition. For this reason and because fruits are
propagated by asexual methods MendePs law does not have here
the same value as for the breeder of self-fertilized crops. There
are also many fruit crops which are totally self-sterile so that
cross-pollination, either natural or artificial, is essential to the
production of fruit. Unlike an annual crop the individual fruit
tree often takes many years to grow before fruiting. For these
reasons methods of handling are often of much greater importance
than methods of breeding. It is, therefore, of utmost importance
that the student first make an intensive study of the botanical
relatives, methods of culture, varieties, and environmental
necessities of the crop before undertaking breeding operations.
ORIGIN AND ANTIQUITY OF SOME FRUITS*
Wild fruits without doubt played an important role in the
food supply of primitive man. As the art of agriculture came
to be developed because of the necessity of obtaining enough
food to supply the increasing human population, the fruit crops
were gradually introduced into cultivation.
Some of our most
prized fruits, as the apple, grape, and plum, have been cultivated
since earliest times; while others, as the strawberry, black raspberry,
and blackberry, have been brought under cultivation
America was discovered.
since^
The wild species from which our fruits have been developed
may still be found today. Wild plums may be found in nearly
every state of the United States, while in central and northern
Asia the wild relatives of apples, pears, apricots, cherries, and
plums are of frequent occurrence.
The wild crabs are found in abundance, in both the Eastern
and the Western Hemispheres. As the cultivated European
1 A paper by WHITE (1916) has been used very freely
261
in this discussion.