ILLUSTRATION OF INBREEDING 



Maize Self-Pollinated for Three Generations Produces One-fourth. Albino Plants 

 — Abnormality Isolated and Bred Out of Part of the Stock 



D. F. Jones 

 Plant Breeder, Connecticut Agricultural Experiment, Station, New Haven, Conn. 



THE noticeable results attending 

 systematic inbreeding of a cross- 

 bred race of plants are the 

 reduction of vegetative vigor 

 and the isolation of abnormalities. The 

 prejudice against inbreeding is largely 

 due to this latter effect. Inbreeding, 

 however, is the quickest way to make 

 abnormal tendencies visible so that they 

 can be eliminated. 



The way in which an abnormality is 

 brought to light by inbreeding is illus- 



trated by a race of Leaming corn which 

 had been self-pollinated for three genera- 

 tions. Two rows of this race in our 

 corn plot this spring produced so many 

 albino seedlings that it was impossible 

 to secure a good stand of plants although 

 an excess of seed was planted. 



Albino seedlings in corn are common. 

 Few fields are without a small number 

 of them, but the percentage is so low 

 as to be of no practical effect. Since 

 chlorophyll reduction or albinism in 



ALBINO AND NORMAL MAIZE PLANTS 



Most fields of Indian corn contain a few albino plants, which lack altogether the chlorophyll 

 or green coloring matter that every plant normally possesses. When a race of plants 

 is inbred, one effect is to accentuate any abnormalities present. Consequently when a 

 race of corn was inbred for three generations, it was natural to expect that the proportion 

 of albinism would be much increased. This photograph shows a hill of Leaming corn 

 grown from seed which had been inbred three generations: it contains three albinos and 

 two normal green plants. (Fig. 10.) 477 



