IV. Miscellaneous Co-op Items

1. Co-op stocks. An effort is being made to grow each stock in our collection at least once every three years. To maintain vigor, especially in the naturally weaker stocks, we shall follow a practice started a few years ago. The co-op stocks are crossed with standard inbreds I (U.S. No. 204) and II (West Branch). The desired characters are then recovered from each of these hybrids, and crosses are then made between these desired sorts from the two sources.

2. Assignments of chromosomes for mapping. In News Letter April 15, 1939, page 39, there is given a list of persons who are mainly responsible for linkage studies on the different chromosomes, and for the building up of linkage stocks. At the Christmas meetings in 1940, this list was examined by the co-operators present, and a few changes were made. The revised assignments follow:

Personals.

(a) Carlos A Krug of Sao Paulo, Brazil, is spending a year in this country, with the special purpose of studying the genetics and cytology of citrus, at Riverside, California. Krug brought to the U.S.A., 60 types of maize collected by his assistant in Bolivia, Peru, Ecuador, and Columbia. These have been added to the Co-op stocks. Small amounts of seed can be spared to cooperators who are especially interested.

(b) D. G. Langham of Venezuela is in this country for a few months, for the purpose of collecting corn and of working on a special problem in connection with his research.

(c) Two of our number, M. M. Rhoades and B. McClintock, will be at Cold Spring Harbor this summer, along with Muller, Wright, Nebel and other geneticists.

(d) R. A. Emerson left Ithaca early in February for a six-weeks vacation in Florida.