In Chapter 42 on the "Properties and uses of duplicate-deficient chromosome complements in maize," by E. B. Patterson in "Maize Breeding and Genetics," edited by D. B. Walden, the following statement appears on p. 696:

"Although individual exceptions are known, adjacent-2 and 3-1 disjunctional patterns from most translocation heterozygotes appear to be infrequent."

This is contrary to evidence presented by Burnham (Genetics 35:445-481, 1950). As stated on p. 677 of Chapter 41:

"In maize, chromosome segregation in ring configurations without crossing over in interstitial segments is two alternate:one adjacent-1:one adjacent-2. In chain-forming interchange heterozygotes, using ones with one break in the satellite of chromosome 6, adjacent-2 segregations are rare regardless of the length of the interstitial segments. The segregation is one alternate:one adjacent-1."

Since Patterson was dealing with interchanges that produce female transmissible (Dp + Df)'s they were probably chain-formers in which adjacent-2 segregations are rare.

We have exchanged letters on the above and we are in agreement.

Charles R. Burnham

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