Plaxt-Breeding for Farmers. 151 



Detasseliiig to prevent self-pollination. 



It has been proven by careful experimentation that corn is reduced 

 markedly in vigor and production as a result of inbreeding and self- 

 fertilization. Planting by the ear-to-row method gives opportunity 

 for considerable inbreeding and self-fertilization and to avoid this it is 

 necessary to detassel certain portions of the breeding-patch from which 

 seed is to be taken. The simplest method of accomplishing this is to 

 detassel one half of each row. In order that this may not interfere with 

 proper pollination each row is detasseled from one end to the middle 

 alternating ends of adjoining rows being detasseled as illustrated 

 below, the dotted line indicating the portion of each row detasseled. 



Row I 



Row 2 



Row 3 



Row 4 



It will be seen from an examination of this method that the seed 

 formed on the detasseled portions of each row will all of it have been 

 cross-fertilized with individuals from another select row which in this 

 first generation is probably quite distantly related. 



The process of detasseling is accomplished by pulling out the tassels 

 before they begin to discharge pollen which will entirely prevent self-- 

 fertilization. In order to do this work thoroughly the field must be gone 

 over every two or three days at the time of tasseling. An examination 

 of all the rows should be made at this time and if any rows are found to 

 show weakness or undesirable characters they should be detasseled 

 throughout so that they will not afifect the remaining rows by crossing with 

 them. 



Making selections from the breeding-plot of corn. 



After detasseling nothing remains to be done until the stalks begin to 

 ripen and the ears to dry. At this time the number of stalks in each row 

 should be counted and recorded. If border rows have been planted these 

 of course should be excluded from the count. It now remains to select 

 the best plants from this patch. The field should be gone over with the 

 ideal type well in mind and the best plants marked. All of these should 

 be taken from the detasseled portions of the different rows. As in 

 making the selections the first year about twice or three times as many 

 ears should be taken as are finally desired. These should be taken from 

 the most productive rows so far as can be determined at this time. It is 

 necessary to take seed from all of the apparently good rows as it is im- 

 possible to tell which are the best rows until the product from the dif- 

 ferent rows is measured and weighed. The select ears from each row 

 should be kept together under the row number and spread out to dry in a 

 warm, well ventilated room. 



