4. Derivatives of maize-teosinte crosses. The segments of chromatin or blocks of genes which distinguish various types of teosinte from maize have been transferred individually by repeated backcrossing to a uniform inbred strain of maize. Stocks derived by this procedure show that the segment which occurs on chromosome No. 4 in Florida teosinte has almost identical counterparts in Durango, Nobogame and "New" teosintes. Whether these counterparts occur on chromosome 4 in each of these teosintes remains to be determined.
These stocks are also useful for testing the effect of teosinte germplasm upon the yield of maize. Preliminary tests indicate that a small amount of teosinte germplasm may improve grain yield. When two or more segments are present, however, even in the heterozygous condition, grain yields are definitely depressed although forage yields may be somewhat improved.
P. C. Mangelsdorf