INHERITANCE— IMPROVEMENT B V BREEDING 2 2 5 



acters for which the ear was selected are being transmitted or chap. 

 whether they are only of a temporary nature. If any one or 

 more ears show fluctuating variability as regards such char- 

 acters, the progeny of those ears can be discarded next season. 



The object of placing the very best ears in the centre, and 

 the worst of the 100 on the outside, is that the same sequence 

 may be preserved in the breeding plot. By this means, and 

 as the grain from each ear will be used to plant only one row 

 of the plot, the grain from all of the best ears will be removed 

 as far as possible from danger of pollination by plants de- 

 rived from poorer ears. In this way the tendency to deteriora- 

 tion, through cross-pollination with poor plants, is reduced to 

 a minimum. 



After this the ears are shelled by means of a hand-sheller ; 

 the cobs of each ten are weighed separately ; the weight of 

 cob deducted from the weight of ear previously taken gives 

 the weight of grain. Being in groups of ten the average 

 weight of individuals in a group can be determined at a glance. 



Each ear is shelled into a paper bag (half-pound bags 

 with folding flap have been found satisfactory) and num- 

 bered with a consecutive number from 1 to 100, preserving 

 carefully the same sequence as that of the final selection. 

 The packets of each breed are then placed in separate 

 boxes, the highest number at the bottom, and carefully 

 labelled ready to be taken to the breeding-plot at planting 

 time. This completes the work of selection for the season. 



181. Selection by Continuous Performance-record. — This 

 consists in the strict and continuous selection of parent ears 

 from among the best progeny of the best plants which have 

 year after year given the best performance-record in the 

 direction desired (i.e. yield, early maturity, drought resistance, 

 etc.). An idea of the method practised is given in Table 

 XLIII following, which shows the sort of record kept each 

 year of the performance of certain strains grown in the breed- 

 ing plot of the Illinois State Experiment Station. Selection 

 for the following year would be made of those ears which give 

 the best record in this analysis. It is noticeable that the nine 

 best ears J are those in the centre of the table, which come from 

 the centre of the breeding plot, and that the best result of all 



1 As regards protein-content, for which the ears were selected. 

 IS 



