Plant Breeding 
J hroughout this discussion where we refer to “Plant Breeding” it should be kept in mind that it applies to 
the Cucurbita family. Plants of most of the Cucurbits are Monoecious—that is they bear both staminate (male 
blossoms) and pistillate (female blossoms) on the same plant. Therefore fertilization is possible either 
within one plant or by cross-pollination between two plants. In a majority of varieties of Muskmelon the plants 
are Andro-monoecious. They bear hermaphroditic as well as staminate flowers. However, in all cases the 
transfer of pollen by artificial means is necessary to obtain fertilization. Usually bees are the chief factor in 
the distribution of pollen. Wind and other causes are not noticeably instrumental in its transfer among vine 
seeds. Under ordinary conditions it is generally considered that about 15 per cent of the blossoms are fertilized 
from adjacent plants while some 85 per cent are pollinated from blossoms of the same plant, although there 
are no definite rules by which this percentage may be determined. The staminate blossoms which produce the pol¬ 
len appear profusely and usually in advance of the pistillate blooms. The pistillate or female bloom appears at 
the end of a tiny fruit and lives for about one day. Unless it does become fertilized during this time the fruit 
eventually withers and dies, although it may appear normal for a number of days, often attaining considerable 
size, the seeds cannot develop within the fruit unless fertilization has been completed. 
Generally growing conditions govern the set of fruits on the vines to some extent. In extremely hot weather 
fertilization is less successful probably because the pollen cannot endure the high temperatures. When fertilization 
has been but partially completed the fruits often appear misshapen or are described among cucumbers as “nub¬ 
bins.” Nubbins and illshapen fruits are almost wholly the cause of improper fertilization or growing conditions. 
This result is not hereditary. About three distinct sets of fruit appear during the growing season in the pro¬ 
duction of seed crops; each set appearing at regular intervals and the final yield depends upon the ability of 
the plant and general conditions. If the fruits are kept picked they will continue to bear throughout the grow¬ 
ing period. 
The simple method of inbreeding has been employed successfully as a means of developing purity within 
a variety. The advantages of breeding or control of pollination are recognized as of much importance in ac¬ 
complishing permanent results in the maintenance of seed stock. To obtain the desired results by inbreeding, a 
thorough knowledge of the procedure must be understood, as well as a definite knowledge of type in the indi¬ 
vidual variety. The usual principle is to start with the seed from a single specimen fruit which shows a major¬ 
ity of the most desirable characteristics. This fruit should come from a vine bearing only true progeny and well 
isolated from other plants of undesirable nature from which it may have become contaminated. 
Inbreeding may be accomplished by the bagging system or by the use of a muslin cover over the complete 
plant. Where bags are used for each individual blossom it must be placed over the young bud before it has 
opened. After the transfer of pollen has been made the female blossom must again be covered for a time to pre¬ 
vent the possibility of pollen from outside sources. In the use of covers over the whole plant the necessity of 
bags is entirely eliminated. The transfer of pollen is more satisfactorily effected by direct contact of the two 
blossoms. 
The progeny of these plants are then chosen from which to continue this process through following genera¬ 
tions until the type has finally been fixed to the satisfaction of the producer. A number of years are ordinarly 
required to obtain permanent results. Properly conducted, the work is most gratifying, as the development of a 
pure line strain is the highest degree of purity in vine seed. It is generally agreed that inbreeding of the cucur¬ 
bits does not reduce vigor, yield, or in any other way detract from quality but on the other hand is inclined to 
build up a more uniform type. 
In our tests we have found a wide variation in the number of fertilizations which are successful among the 
various Cucurbits. In cucumber over a given season we have found that nearly 90 per cent of the hand pollina¬ 
tions were successful. Whereas in others, such as Squash and Muskmelons, at times a very small per cent has 
been recorded. 
When two pure line strains are crossed for the purpose of deriving a new variety the result is hybridization. 
According to the Mendel law of plant heredity the Fi generation of a cross will exhibit phenotypically all of the 
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