LINKAGE SUMMARY

In the course of the past year a number of developments have occurred in tomato linkage. Three more chromosomes have been assigned to willing volunteers, Drs. Kerr, Notani, and Williams, bringing the number of assigned chromosomes to 11, which are summarized as follows:


Chromosome  Group      Personnel

1           III        Lesley, Soost
2             I        Butler, Clayberg   (ms\5, ms\15),
                       Jenkins (0)
3            II        Bohn
4            XI        Notani
6            IV        Gilbert
7           X, XII     H. W. Young
8           VI, VIII   Rick, Griffing
9                      Rick
10          VII        Kerr
            V          Burdick, Mertens
            rv-sf      Williams

Screening unlocated genes:  Burdick, Butler, Kerr,
                            Paddock, Pollack, Rick.

Linkage for disease resistance: Andrus, Barham, Gilbert,
                                Kerr, Reynard, Walter.

Unassigned groups:  IX (dm)
The services of additional volunteers would be welcome for work on the unassigned group and other projects. The assignment of chromosome 9 to Rick is only a temporary arrangement made at the time that wd was the only known marker for that chromosome. Now that the better marker ah has been found, he would be willing to be relieved of that responsibility. Additional help will inevitably be needed for the larger groups also.

As mentioned in the Foreword, Dr. Hans Stubbe has contributed for linkage studies seeds of the 100 new X-ray-induced mutants described in his first two articles in Kulturpflanzen. These have been distributed to Drs. Butler, Kerr, Paddock, and Rick for screening to their respective linkage groups and assignment to proper referee.

A number of new linkages are reported in this issue, but rather few are based on three-point or otherwise adequately provide a good estimate of loci for new genes. A revised chromosome map would therefore consist of the map issued in TGC 8 with an enumeration of new genes added to certain chromosomes and very few changes in loci. Since the linkage picture has changed to such a slight extent, we feel the issuing of a revised map in this Report is scarcely justified. With the current amount of linkage work in progress, however, a revised map would certainly be timely in TGC 10.