CORN BREEDING 39 
bags should be well made. Nothing is more distressing than to go 
to the field after a storm and find the work of days lost because bags 
have become unglued, torn, or blown off. The larger bags may be 
fastened to the ear shoot, culm, or both, with string, wire, or a paper 
clip. The smaller bags may be slipped over the ear shoot and between 
it and the culm, utilizing the natural pressure between the ear shoot 
and culm to hold them in place (pi. 9, A). The latter practice may 
be followed after some experience, with negligible losses due to the 
bags blowing off. 
The tassel bags, used for collecting pollen and later for protecting 
the pollinated shoot or ear, must be larger (pi. 9, C and D). Square- 
bottom bags made of good manila or hemp stock. have proved very 
satisfactory for tassel bags. These may be fastened around the stem 
of the tassel with string, wire, or a paper clip. Bags of the 12-pound 
size are convenient for large varieties of corn, and 10-pound, 8- 
pound, or even 4-pound bags are better for some of the smaller sorts. 
As the plants begin to tassel the plat is visited each day and ear 
shoots on desirable plants are bagged before their silks have emerged. 
Nothing more is necessary until the first silks of the bagged ear 
shoots appear. Other things being equal, the number of kernels 
obtained will depend upon the number of silks pollinated. Conse- 
quently, it is better not to pollinate until most of the silks have 
emerged. The silks are receptive even before they emerge from the 
enveloping husks and usually remain receptive for several days 
afterwards. Pollination should not be delayed longer than neces- 
sary, however, both because some of the silks may have become 
unreceptive and because too large a mass of silks interferes with 
pollination and promotes the development of molds after the polli- 
nated shoot is rebagged. It has been found convenient and efficient 
to cut off from one-half to 2 inches of the ear shoot after the first 
silks have emerged (pi. 9, B). A shoot cut back one day usually 
will present an even brush of silks ready to pollinate on the next 
(pi. 9, C), although occasionally this is not the case. 
Pollen should be used only from tassels that have been bagged 
since the preceding day. This insures that any stray pollen which 
may have lodged on the tassel prior to bagging will have lost its 
viability. When self -pollinating, if the tassel is bagged at the time 
the ear shoot is cut back the bagged tassels mark the plants that 
will be ready to pollinate the next day. This is a convenience and 
permits these plants to be handled immediately in case of a threat- 
ened shower which would wet the tassel bags and delay pollination 
until they had dried again and fresh pollen had been shed. 
Every care should be taken to prevent contamination from stray 
pollen. The air is filled with pollen at pollinating time, and the 
corn leaves and the hands and clothing of the operator carry liberal 
quantities. The silks should be exposed as little as possible, and 
should not be allowed to come in contact with anything that may 
carry pollen. Tearing off the end of the shoot bag and applying the 
pollen through the opening reduces the chances for contamination. 
Another practice is to fold the tassel bag so that the pollen will not 
pour out, and to cover the shoot with the open part of the tassel bag- 
before removing the bag protecting the shoot. The tassel bag then 
may be straightened up quickly so that the pollen will fall on the 
